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Sources  of Energy Chapter Wise Important Questions Class 10 Science

PREVIOUS YEARS QUESTIONS

Very Short Answer Type Questions [1 Mark] – Year 2015

1.Name any two fossil fuels.
Ans. A good fuel is the one which

•  has high calorific value,
•  is non-polluting,
•  is easy to transport and easily available,
•  has moderate ignition temperature.

2.Mention the purpose of blackening the interior of a solar cooker.
Answer. The purpose of blackening the interior of a solar cooker is that the black surface absorbs more heat radiations of incident solar energy (about 98%) as compare to white or other light coloured surface

Short Answer Type Question[ll] [3 Marks] – Year 2015

3.Why do people oppose the construction of Tehri Dam on the river Ganga and Sardar sarover project on the river Narmada.  (Or)
Mention three disadvantage of producing hydroelectricity by constructing the dams.(Or)
List any three ways in which construction of dams for production of electricity adversely affects the environment of that place.
Answer. 

1. Large area is required to build the dam that  result rehabilitation of displaced people.
2. Large eco-systems are destroyed when submerged under the water in dams.
3. The vegetation which is submerged rots under anaerobic conditions and gives rise to large amounts of methane gas which leads to a green-house effect.

4. Reena’s father works with a company that builds dams. Once he took her to the site where a dam was being built. Reena saw a group of people sitting there and shouting slogans against the building of dam. She talked the group of people and asked them about their problems and then discussed it with her father. She then tried to convince the people to talk with the authorities and come to an amicable solution. The discussion was successful. Reena’s father was very proud of his daughter. Now answer the following questions:
(i) Why was Reena’s father proud of his daughter?
(ii)Why was the group of people protesting against the building of dam?
(iii) Reena’s contribution to the peaceful resolution of the conflict proved to boon for many citizens of the country. How?
Answer.
(i) Because she convinced the people by explaining them the advantage of constructing dam and come with a solution of rehabilitation of displaced peoples. So the contribution to the peaceful resolution of the conflict make Reena’s father proud of his daughter.
(ii)The group of people protesting against the building of dam because of following disadvantages
(a) A large area of agricultural land and human habitation are sacrificed as it get submerged at the dam site.
(b) Large ecosystems are destroyed when submerged under water.
(c) The decomposition of vegetation under anaerobic condition produces methane gas which is also a greenhouse gas.
(iii)(a) The citizens are not affected by flood as it can be controlled by storing the water behind the dam.
(b) Farmers get benefited as water for irrigation is available for the whole year.
(c) Low cost of production of electricity gives monetary gain which is a boon to citizens.

5.Bio gas is an excellent fuel. Justify the statement by giving two reasons. Mention the main constituents of bio gas along with its percentage.
Answer. 
(i) It burns without smoke and leave no residue therefore causes no atmospheric pollution.
(ii)Its heating capacity is high, i.e. it has high calorific value. Main constituents of bio gas: The composition of bio gas varies depending upon the nature of organic matter feeding in’the digester and advanced waste treatment technology. The typical composition of bio gas is
Methane                                50 – 75%
Carbon dioxide                     25 – 50%
Nitrogen                                   0 – 10%
Hydrogen                                 0 – 1%
Hydrogen sulphide                0 – 3%

6.(a) Define tidal energy.
(b) Explain how the tidal energy is harnessed and write one limitation of the use of tidal energy.
Answer.
(a) Tidal energy: The energy produced by the surge of ocean water during high and low tides due to difference in sea-levels is called tidal energy. The high and low tides occur due to the gravitational pull of the moon. This causes enormous movement of water.
(b) Tidal energy is harnessed by constructing a dam near the shores. During the high tides water flows into the dam and during the low tides, water flows out. This flowing water rotates the turbine, present at the opening of the dam and produces electricity.

7. Define process of nuclear fission. Writ the steps involved in generating electricity in a nuclear reactor.
Answer. Nuclear Fission: The process in which a heavy nucleus (such as uranium, plutonium or thorium) is broken into two nearly equal fragments when bombarded with low-energy neutrons and a tremendous amount of energy is released. This process is called nuclear fission.
Steps involved in generating electricity:

1. The fuel rods full of uranium pellets are placed in a nuclear reactor chamber.
2. Low-energy neutrons are bombarded on uranium fuel rod.
3.  A self-sustaining fission chain reaction starts that releases energy at a controlled rate.
4. With this heat the reactor converts water to steam at a high temperature and pressure.
5. This high temperature and pressure steam spins generator turbines producing electricity.
6. The steam cools back into water, which can then be used over again.

Long Answer Type Question [5 Marks] – Year 2015

8.Nikhil and Neha went to a remote village in Kerala to meet their grandmother. They were surprised to see a biogas plant in Mr. Nair’s house in the neighbourhood. There were plenty of livestocks and the household used cooking gas from the plant. Also their farms had rich vegetation. They contacted sarpanch of the village and convinced him to set up a biogas plant for village community.
(a) Mention the values displayed by Mr. Nair, Nikhil and Neha.
(b) Explain the possible arguments given by Nikhil and Neha to the sarpanch to convince him to set up community biogas plant.
Answer.
(a) Mr Nair: Higher degree of general awareness, helping nature.
Nikhil and Neha: Knowledge sharing.
• helping nature.
• concern for community advantage.
(b) Possible arguments given by Nikhil and Neha in favour to set up community biogas plant, to the sarpanch on

1. Economical source of energy.
2.  Cleanliness of the whole village.
3.  Use of slurry left behind as mannar which is rich in nitrogen and phosphorous.
4. It reduces air pollution and greenhouse effect.
5.  It raises the standard of living.
6. It is beneficial to entire village community. Basically they discuss and explain the advantages of community bio gas plant for the’entire village.

9.Solar cooker takes more time as compared to the LPG to boil potato or rice, yet Kunal uses solar cooker for such type of cooking:
(i) Why does Kunal uses Solar cooker instead of LPG? Give reasons for your answer.
(ii) Name the phenomenon which is responsible for obtaining high temperature in solar cooker.
Answer.
(a)(i) There are no energy losses while cooking on the solar cooker as the food gets cooked in a controlled environment whereas cooking on the LPG leads to maximum percentage of energy loss.
(ii) Temperature controlled cooking retains the nutrient value of the food.
(iii) Using the solar cooker, LPG can be served which result reduction in the emission of  CO₂.
(iv) It saves a lot of prestigious time which is normally consumed for cooking purpose.
(b) Greenhouse effect.

10. Manoj’s father works in a nuclear power reactor. He asked his father to take him for a visit to nuclear power reactor. But his father was not keen to take him there. Now answer the following questions:
(i) What could be the possible reason of Manoj’s father not taking him to the nuclear power reactor?
(ii) Write one advantages and one disadvantage of setting up a nuclear power reactor. .
Answer.
(a) (i) Safety concerns.
(ii) Health concerns.
(b) Advantage: From a small amount of nuclear fuel, a large amount of energy is released in a nuclear power reactor.
Disadvantage: There is risk of harmful radiation leakage from nuclear waste.

Very Short Answer Type Questions [1 Mark] – Year 2014

11. Name the part of a biogas plant where reactions take place in the absence of oxygen.
Answer. Digester chamber.

12. Name the kind of energy possessed by wind and the device used to harness it.
Answer. Kinetic energy, wind mill.

13. List two non-conventional sources of energy.
Answer. Geothermal, solar, biomass, water, wind are the non-conventional sources of energy, (any two)

14. A black surface absorbs more heat radiations as compared to a white or a
reflecting surface under identical conditions. List two solar devices which make use of this property in their design.
Answer. Solar cooker, solar water heater.

15. Name any two elements that are used in fabricating solar cells.
Answer. Germanium, Silicon.

16. Why a solar cooker painted black form outside?
Answer. Black surface absorbs more heat as compared to white or reflecting surface under identical conditions.

Short Answer Type Question [I] [2 Marks] – Year 2014

17. Define fuel. List any two characteristics that you would look for in a good fuel.
Answer. A substance that produces useful energy when it burn or undergoes a chemical f or nuclear reaction. The fuel such as coal, wood, oil, or gas provides energy when burned. A good fuel is the one which produces a huge amount of heat on burning. It does not produce a lot of smoke and is easily available.

Short Answer Type Question[ll] [3 Marks] – Year 2014

18 State any three reasons to justify that LPG is considered as an ideal fuel.
Answer. LPG is considered as an ideal fuel because

1.  It is easy to store, handle and transport.
2.  It produces large amount of heat on burning.
3.  It does not leave any residue on burning,

19 Sate any three advantages of charcoal over wood.
Answer. Advantages of charcoal over wood

1.  It has higher calorific value, i.e. higher heat generating efficiency.
2. Charcoal does not produce smoke on burning so it is a clean fuel.
3.  It is easier to transport and ready to use in a convenient dry and broken-up form.

20. Ramesh is a student of standard X. He organized many activities in his school to convey the students about the various advantages and disadvantages of using renewable and non-renewable sources of energy. Many students of the school took part and concluded about the best choices of energy sources on this basis.
Answer the following questions:
(i) What activities Ramesh might have had assigned for the students?
(ii) Name any two renewable sources of energy.
(in) Which two values are reflected in Ramesh’s thought and action?
Answer. 
(i) Activities that Ramesh have had assigned for the students are:
(a) Hands on projects related to renewable and non-renewable sources of energy.
(b) Photograph exhibitions on the topic “use of fossil fuel and its impact on the environment.”
(c) Essay writing competition on a “renewable energy technology that could potentially be used for community.”
(d) Group discussion on advantages and disadvantages of using renewable and non-renewable sources of energy for selection of best source of energy.
(ii) Solar energy, hydro energy.
(iii) Ramesh’s thought: Higher degree of general awareness proper use of renewable source of energy.
Ramesh’s action: Concern for community advantage and good management.

21. Megha asked her mother to install a solar water heater on the roof top. Her mother asked about the need of such installation. Megha convinced her mother and succeeded in setting up a solar water heater on her roof top.
(i) State one advantage of installing the solar water heater to Megha’s family and to the society.
(ii) What qualities of Megha are reflected in her action?
(iii) State one limitation in using solar water heater.
Answer.
(i) Advantage of solar water heater (any one)
(a) Once solar water heater installed, the family and society never need to pay for heating up the water again.
(b) Megha’s family and society make their contribution to the nation to curb the emission of green house gases.
(ii) General awareness, concern for community advantage and proper use of ‘ renewable source energy.
(iii) (a) It does not work at night as well as on cloudy day.
(b) Relatively low heating system efficiency of passive solar water.

22. Mariyam made a solar cooker on her own. She used a white metallic box with a lid. She put the food in the solar cooker for heating and closed the lid. But she did not get good results. She then consulted her teacher to know her mistakes. Her teacher pointed out her mistakes, which she later rectified.
(a) According to you, which two mistakes were made by Mariyam and what
did she do to rectify them?
(b) Which qualities of Mariyam are rectified in her action.
answer.
(a) The possible mistakes were made by Mariyam are:

•  The outer and interior of solar cooker might not have been blackened.
• Instead of using glass lid she might have been used plastic cover.
•  The solar cooker might not have been insulated properly.
•  The cooker utensil used for cooking might not have been blackened.

(b) • Gaining practical knowledge of what she have learned in theory. She wanted to adopt the eco-friendly life style.

23. Aditya suggests his family to install a solar water heater at their residence. But
some of the family members were in favour of installing an electric geyser.
Ultimately the family got water heater installed.
(a) Which according to you was correct? Give two reasons in support of your answer.
(b) Mention two possible changes in the thinking of the family members
because of the arguments Given by Aditya.
answer. (a) The decision of installing the solar water heater was correct this is due to
(i) Their system use solar energy which is a renewable source of energy and free.
(ii)It will reduce our dependence on fossil fuel, improving on our energy security and reduce the country import bill for fuel.
(b) Two possible changes in the thinking of the family members because of the arguments given by Aditya are:
(i) We should conserve the non-renewable fuels for application for which renewable source of energy is not easily available.
(ii)Solar water heating is good investment and cost effective. It is one of the safe and efficient way to deliver hot water free of cost.

24. Traffic jams, outside the school gate was a common sight since most of the students came on their own cars. This became a topic for discussion on every P.T.A meeting. On one such P.T.A meeting, the principle pointed out the examples of four of their teachers who were carpooling for the past several
years. She asked the parents to adopt this method to sort out the problem.
(i) List two values shown by the teachers mentioned by the principal.
(i) Explain two advantages that will occur if more parents emulate the examples of these teachers.
answer.
(a) The two values shown by the teachers mentioned by the principle are:
(i) Eco-friendly life style.
(ii) Co-ordination and friendship.
(b) (i) Reduction in air pollution and traffic congestion: Car pooling reduces the emission of CO₂ into the atmosphere as every car pooling participant takes another car off the road.
(ii) Save money: Car pooling saves money by using less fuel. It reduces the cost involved in repetitive or long distance journey.

25. On returning home, Neha, a IXth std. student noticed that her 6 years old brother Neresh, watching T.V in the afternoon with all the lights and fans ‘on’. She noticed that the windows were closed and curtains were drawn, which made the room dark, so, Naresh had put on the lights. She calmly opened the windows, drew the curtain aside, which illuminated and aerated the room. Then she made Naresh put “off” the lights and made him understand the reason behind her action. (Assume that they are getting electric supply from Thermal Power Plant)
(a) List the two value exhibited by Neha.
(b) Explain how she tried to give same values to her brother.
answer.(a) The values exhibited by Neha are:
(i) Responsible citizen in the conservation of energy resources.
(ii) Adopt fuel and money saving technique in her life.
(b) Neha tried to give the same values to her brother Naresh by opening the windows, draw the curtain aside, which illuminated and aerated the room. This way she shows the practice of adopting renewable sources of energy like solar energy and conserve the fossil fuel like coal.

Very Short Answer Type Questions [1 Mark] – Year 2013

26. What is acid rain? 
answer. Acid rain: The rain containing the acidic oxides such as oxides of carbon, nitrogen and sulphur.

27.Write the name of the substance whose vapours are used to run the turbine of the generator of ocean thermal energy plant.
answer. Ammonia.

28. Mention the minimum temperature difference required between surface water and water at a depth of upto 2 km in an ocean thermal energy plant.
answer. 20 °C or 293 K in trapping geothermal energy

Short Answer Type Questions [II] [3 Marks] – Year 2013

29. Distinguish between renewable and non-renewable sources of energy. Also give an example of each of these sources.
answer.
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30. State the principle of working of ocean thermal energy conversion plant.
Explain how the plant works? Write one essential condition for it to operate
properly.
answer. Principle of working of OTEC: The water at the surface of the ocean is warmer
than the water at deeper depths. This temperature difference can be used by
Ocean Thermal Energy Conversion (OTEC) systems to generate electricity.
Working of OTEC:

• In OTEC plant, the energy of warm surface water is used to convert low i boiling point liquid ammonia into gaseous state.
•  The vapour of ammonia at high pressure is used to spin the turbines of generators converting the Ocean thermal energy to electricity.
•  The used vapour pass through the condenser where cold water, pumped from the deeper parts of ocean condenses ammonia vapour back into a liquid.
• This process is repeated again and again ,to get continuous production of electricity.
  Essential condition for it to operate properly: The temperature difference between the warmer water at the surface and colder water at depths up to 2 km should be 293 K (20°C) or more.

Very Short Answer Type Questions [1 Mark] – Year 2012

31.Name one fuel used in nuclear reactor.
answer. Uranium-235.

32.Name any two elements that are used in fabricating solar cells.
answer. Germanium, Silicon.

33.Name the reaction responsible for large energy production in the sun.
answer. Nuclear fusion.

Short Answer Type Questions [II] [3 Marks] – Year 2012

34.Mention why is it not possible to make use of solar cells to meet all our energy needs? State three reasons to support your answer. Also mention three uses of solar cells.
answer. It is not possible to make use of solar cells to meet all our energy needs because:
(i) of limited availability of special grade semiconducting materials such as silicon and germanium.
(ii)solar cells have lower efficiency as they depend entirely on intensity of solar radiation.
(iii) the process of manufacturing of solar cells is very expensive, silver used for interconnection of cells in the panel further adds to the cost.
Uses of solar cells:
(i) They provide electric power to satellites and space probes.
(ii) They provide electric power to off-shore drilling platforms and light houses.
(iii) TV relay stations or wireless transmission systems located in remote areas use solar panels to get electric power.

35.Out of two elements A and B with mass number 2 and 235 respectively, which one is suitable for making ,
(a) a nuclear reactor,
(b) a hydrogen bomb?
Name the nuclear reaction involved in each case. Write one difference between the two types of nuclear reactions.
answer.
(a) For a nuclear reactor— element ‘B’ with mass number 235 is suitable as a fuel in a nuclear reactor.
(b) For a hydrogen bomb— element ‘A’ with mass number 2 is suitable for making the hydrogen bomb.
The nuclear reaction involved in
(a) nuclear reactor is nuclear fission reaction and
(b) nuclear bomb is nuclear fusion reaction.
Difference between fission and fusion:
Fusion reaction releases much greater energy with non-radioactive products than the energy released in fission reaction with radioactive products.

Very Short Answer Type Questions [1 Mark] – Year 2011

36. List two nutrients that the slurry left behind in the biogas plant contain.
answer. Nitrogen and phosphorous.

37. Biogas is also known as gobar gas. Justify.
answer. Starting material for biogas is mainly cow dung. So, it is also known as gobar gas.

38. List two practical uses of biogas in rural areas.
answer. Practical uses of biogas in rural area are:

1.  It is an excellent fuel which burns without smoke with high heating capacity.
2.  It is also used for lighting.

Short Answer Type Questions[l] [2 Marks] – Year 2011

39. Bio gas is considered to be a boon to the farmers. Give reasons.
answer.

1. It is the source of excellent manure, rich in nitrogen and phosphorous which
   can be obtained from the biogas plant in addition to biogas.
2.  It provides the safe, efficient and profitable disposal method for bio-waste and sewage material.

40. What are the advantages of nuclear energy?
answer. Advantages of nuclear energy are:

1.  A small quantity of nuclear fuel is needed to produce a large amount of useful energy.
2.  Nuclear power plant produces less atmospheric pollution than thermal power plants, if the nuclear fission reaction is performed properly.
3.  Small amount of nuclear fuel can run a nuclear power plant over a long period of time. There is no need of inserting the nuclear fuel in the nuclear reactor again and again in a short period as in case of thermal power plant.

41. What is a solar cell panel? Mention any three of its applications.
answer. A large number of solar cells combined in an arrangement to obtain large electrical power is called solar cell panel.
Applications of solar cell panel are:
It provides the electric power for the:

1. working of artificial satellites stationed in outer space,
2.  running of irrigation water pumps by the farmers in rural areas,
3.  street lighting in remote areas.

42. Out of two solar cookers, one was covered with a plane glass slab and the other was left open. Which of the two solar cookers will be more efficient and why?
answer. The solar cooker which was covered with a plane glass slab would be more efficient. The glass lid allows the heat radiation from sun to enter the solar cooker but does not allow the reflected heat radiation to escape or go outside the box. Thus, heat trapped inside the box increases the temperature. Glass lid also reduces heat loss due to reflection.

Short Answer Type Questions [II] [3 Marks] Year 2011

43.List any three hazards of nuclear waste. How does the disposal of nuclear waste pose a problem for the plant and animal life?
answer. Hazards of nuclear wastes are:

1.  Nuclear waste contains radioactive substances which emit harmful nuclear radiations.
2. There is a high risk of environmental contamination.
3. It is highly toxic.
   Effect of nuclear waste on plant and animal life is:
   The radiations emitted from the nuclear waste penetrate deep inside the human or animal body where they can damage biological cells thereby initiate cancer or causes genetic disease.
   Increased mortality of plants, soil invertebrates and mammals and reproductive losses in plants and animals have also been observed.

44. (a) Charcoal is a better fuel than wood. Why? .
(b) How does biogas plant help to reduce the problem of pollution?
answer.
(a) Charcoal is considered to be a better fuel than wood because:

1.  It burns without flames.
2. It is comparatively smokeless.
3. It has higher calorific value, i.e. higher heat generating efficiency than wood.

(b) Biogas plant helps to reduce the problem of pollution in the following ways.

1.  It provides better sanitation due to safe disposal of bio-waste and sewage material.
2. Biogas obtained from this plant produces less smoke on burning. (Hi) The residue left can be used as a manure which can be used as an alternative
   of fertilizers. Thus, it prevents soil and water from degradation.

45. (a) What is geothermal energy?
(b) What are the advantages of wind energy?
answer.
(a) The heat energy obtained from the molten rocks formed in the deeper hot regions inside the earth are called geothermal energy.
(b) Advantages of wind energy are:

1.  It is an inexhaustible source of energy.
2. It does not cause any environmental pollution.
3.  It is available at free of cost.

46. (a) How does construction of dams across the river get linked with production of greenhouse gases?
(b) How do technological inputs improve the efficiency of biomass fuels?
answer.
 (a) A vast variety of plants get submerged in water, rot under anaerobic conditions and produce large amount of greenhouse gases such as methane.
(b) Traditional uses of biomass fuels are not only efficient but they also produce a lot of pollutants which are hazardous to health. Therefore, technological inputs are necessary to improve the efficiency of these fuels and make them environment friendly. With the help of technology, smokeless chulhas and biogas plants have been designed.

Short Answer Type Questions [2 Marks] -Year 2010

47. Mention any four limitations in harnessing wind energy on a large scale.
answer. Limitations in harnessing wind energy are:

1.  Speed of wind is not available at all time and at all places.
2. To establish the wind energy farm, a large area of land is needed.
3.  Speed of wind should be higher than 15 km/h to harness the wind energy.
4. Construction of windmill and its installation is very expensive.

48. What happens when wood is burnt in a limited supply of oxygen? Name the residue left behind after the reaction and state two advantages of using this residue as a fuel over wood.
answer. When wood is burnt in a limited supply of oxygen, volatile materials present in it get removed and cooled to get wood tar and wood gas.
The black residue left behind aftqr the reaction is known as charcoal. Advantages of using charcoal as a fuel over wood are:

1.  Burning of charcoal does not produce smoke. On the other hand, wood produces a lot of smoke on burning.
2. For a given quantity, charcoal produces ,more heat than wood.

49. Name four gases commonly present in biogas. State two advantages of using this gas over fossil fuels.
answer.  Methane, carbon dioxide, hydrogen and hydrogen sulphide.
Advantages of using biogas over fossil fuels are:

1.  Biogas burns without smoke, leaves no residue unlike coal.
2. Biogas is cheaper as compared to fossil fuels.

50. How are the wastes produced in nuclear power plants different from those produced in a thermal power plants ? What happens to the waste of a nuclear power plant?
answer.The waste obtained from nuclear power plants is highly radioactive in nature which emits harmful radiations, whereas waste produced in a thermal power plant is non-radioactive.
Management of nuclear waste is given as follows:

1.  Some products of nuclear waste are buried in sealed steel/lead containers for a long term storage, buried under the ground or dumped in vacated coal mines.
2.  Other waste products transforms into less harmful products or to products with a shorter half life.

Short Answer Type Questions [2 Marks] -Year 2009

51. In a solar cooker, the following arrangements are made. Write one function of each arrangement.
(a) The box is made of insulating material such as plastic or wood.
(b) The inner walls of the box are painted black.
(c) The box is covered with a transparent glass sheet.
(d) A plane mirror is hinged at an angle at the top of the box.
answer. 
(a) To avoid loss of heat from solar cooker to the surroundings.
(b) Black surface absorbs more heat radiations of incident energy.
(c) Transparent glass sheet does not allow the reflected heat radiation to go outside the box.
(d) To increase the amount of solar energy incident on the transparent glass sheet.

52. Describe how hydro energy can be converted into electrical energy. Write any
two limitations of hydro energy.
answer. Conversion of hydro energy into electrical energy

• High rise dams are constructed on the river to obstruct the flow of water to collect it at a suitable height. The stored water has a lot of potential energy.
• The water from a suitable height is allowed to fall on the blades of a turbine located at the bottom of a dam through a pipe.
• Kinetic energy of flowing water rotates the turbine rapidly. Rotation of turbine helps the armature coil of generator to rotate rapidly in the magnetic field. Thus, hydroelectricity is generated.
  Limitations of hydro energy:
  (i) All river-sites are not suitable for construction of dams.
  (ii) Large ecosystems are destroyed when submerged under the water in dam.

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Carbon and its Compounds Chapter Wise Important Questions Class 10 Science

Important QuestionsNCERT SolutionsSample PapersNCERT Exemplar Solutions

VERY SHORT ANSWER TYPE QUESTION [1 Mark] – Year 2007

Question.1 Give the names of the following functional groups:
(i) —OH (ii) —COOH
Ansswer. (i) Alcohol group (ii) Carboxylic acid group

VERY SHORT ANSWER TYPE QUESTION [1 Mark] – Year 2008

Question.2 What is the difference in the molecular formula of any two consecutive members of a homologous series of organic compounds?
Answer. —CH₂— is the difference in the molecular formula of any two consecutive members of a homologous series of organic compounds.

SHORT ANSWER TYPE QUESTIONS[I] [2 Marks] – Year 2008

Question.3
(a) Give a chemical test to distinguish between saturated and unsaturated  hydrocarbons.
(b) (i) Name the products formed when ethanol burns in air. ‘
(ii) What two forms of energy are liberated on burning alcohol?
(c) Why is the reaction between methane and chlorine considered a substitution
reaction?
Answer.
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Question.4
(a) Why are covalent compounds generally poor conductors of electricity?
(b) Name the following compound:
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(c) Name the gas evolved when ethanoic acid is added to sodium carbonate. How would you prove the presence of this gas?
Answer.
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VERY SHORT ANSWER TYPE QUESTIONS [1 Mark] – Year 2009

Question.5 Name the carbon compound which on heating with excess of concentrated sulphuric acid at 443 K gives ethene.
Answer.
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Question.6 What is meant by a sturated hydrocarbon?
Answer. Those hydrocarbons in w hich valency of carbon is satisfied by single bonds only are called sturated hydrocarbons.

Question.7 Name the compound formed when ethanol is warmed with ethanoic acid in the
presence of a few drops of cone.H₂S₀₄
Answer.
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Question.8 Draw the structure of CH₃COOH molecule.
Answer.
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Question.9 Draw the structure of ethanol molecule.
Answer.
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Question.10 What happens when a small piece of sodium is dropped into ethanol? 
Answer. Hydrogen gas will be evolved.
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SHORT ANSWER TYPE QUESTIONS[II] [3 Marks] – Year 2009

Question.11 What is meant by a functional group in an organic compound? Name the functional group present in
(i) CH₃CH₂OH
(ii) CH₃COOH
(b) State one point of difference between soap and synthetic detergent.
Answer.
(a) Functional group is an atom or group of atoms or reactive part of compound, which determines chemical properties of compounds.
(i) —OH (Alcohol)
(ii) —COOH (Carboxylic acid)
(b) Soaps do not work well with hard water, detergents work well with hard water.

Question.12 Give reasons for the following observations:
(a) The element carbon forms a very large number of compounds.
(b) Air holes of a gas burner have to be adjusted when the heated vessels get blackened by the flame.
(c) Use of synthetic detergents causes pollution of water.
Answer.
(a) Carbon forms large number of compounds since carbon is small in size and can form stable covalent bonds (catenation) and it shows tetravalency.
(b) Air holes of gas burner are made open (adjusted) so that air can pass through, which is needed for complete combustion, so that heated vessels do not get blackened.
(c) Some synthetic detergents are non-biodegradable, therefore, cause pollution of water.

Question.13 What is ethanoic acid? Write the formula of the functional group present in this acid.
What special name is given to its 5 – 8% solution in water? How does ethanoic acid react with sodium carbonate? Write a chemical equation of the reaction and common name of the salt produced.
Answer.
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VERY SHORT ANSWER TYPE QUESTIONS[1 Mark] – Year 2010

Question.14 State two characteristic features of carbon which when put together give rise to large
number of carbon compounds.
Answer. (i) Catenation (ii) Tetravalency of carbon

Question.15 Write the structural formula of chloroethane.
Answer.
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SHORT ANSWER TYPE QUESTIONS[I] [2 Marks] – Year 2010

Question.16 Write the name and molecular formula of an organic compound having its name suffixed with ‘-ol and having two carbon atoms in the molecule. With the help of a
balanced chemical equation indicate what happens when it is heated with excess of r cone.H₂S_04.
Answer.
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Question.17 Write the names and molecular formula of two organic compounds having functional r group suffixed as ‘-oic acid’. With the help of a balanced chemical equation and explain what happens when any one of them reacts with sodium hydroxide.
Answer.
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Question.18 What is a homologous series? Which two of the following organic compounds belong
to the same homologous? 
CH₃ ,C₂H₆, C₂H₆O, C₂H₆O_2,CH₄O     
Answer.      
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SHORT ANSWER TYPE QUEST10NS[II] [3 Marks] – Year 2010

Question.19 Name the functional group of organic compounds that can be hydrogenated. With the help of suitable example explain the process of hydrogenation mentioning the conditions of the reaction and any one change in physical property with the formation of the product. Name any one natural source of organic compounds that are hydrogenated.
Answer.
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When unsaturated hydrocarbons are heated with hydrogen in the presence of nickel as catalyst, saturated hydrocarbons are formed. If the starting unsaturated hydrocarbons are liquids, they will change into solids. Vegetable oils are hydrogenated to form vegetable ghee. Plants are natural sources of vegetable oils which can be hydrogenated.

Question.20 An ester has the molecular formula C₄H₈O₂. Write its structural formula. What happens when this ester is heated in the presence of sodium hydroxide solution? Write the balanced chemical equation for the reaction and name the products. What is a saponification reaction?
Answer.
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Question.21 An organic compound ‘A’ is an essential constituent of wine and beer. Oxidation of ‘A’ yields an organic acid ‘B’ which is present in vinegar. Name the compounds ‘A’ and ‘B’ and write their structural formula. What happens when ‘A’ and ‘B’ react in the presence of an acid catalyst? Write the chemical equation for the reaction.
Answer.
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Question.22 What is ethanol? State its two properties. What happens when it is heated with excess of cone. H₂SO₄ at 443 K? What role does cone. H₂SO₄ play in this reaction? Write chemical equation of the reaction involved and the structural formula of the main product formed.
Answer.
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Question.23 With the help of balanced chemical equations explain what happens when ethanol is heated with (i) alkaline solution of potassium permanganate, (ii) excess concentrated sulphuric acid at 443 K. Mention any two uses of ethanol. 
Answer.
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VERY SHORT ANSWER TYPE QUESTIONS [1 Mark] – Year 2011

Question.24 How many covalent bonds are there in a molecule of ethane (C₂H₆)?
Answer. There are 7 covalent bonds in a molecule of ethane.

Question.25 Write the electron dot structure of ethene molecule (C₂H₄).
Answer.
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Question.26 Write the electron dot structure of ethane molecule (C₂H₆).
Answer.
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Question.27 Draw the structure of butanone molecule, CH₃COC₂H₅.
Answer.
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Question.28 Draw the structure of the hexanal molecule, C₅H₁₁CHO.
Answer.
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Question.29 Butanone is a four carbon per molecule compound. Name the functional group present in it.
Answer. Ketone

Question.30 Name the following compound:
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Answer. 1-Hexyne is IUPAC name of the compound.

SHORT ANSWER TYPE QUESTION[II] [3 Marks] – Year 2011

Question.31 What is an ‘esterification’ reaction? Describe an activity to show esterification.
Answer.
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Question.32 Out of HCI and CH₃COOH, which one is a weak acid and why? Describe an activity to
support your answer.
Answer. Acetic acid ( CH₃COOH) is a weaker acid because it does not dissociate completely into its ions in aqueous solution. .
Activity: Add zinc metal in HCI and CH₃COOH respectively. The hydrogen gas will be evolved faster in HCI and slowly in CH₃COOH. It shows acetic acid is a weak acid.
Alternative Method:
If we use pH paper, the colour of pH paper will be dark red in HCI and light red in CH₃COOH which shows HCI is a strong acid and CH₃COOH is a weak acid.

Question.33Write chemical equations for what happens when
(i) sodium metal is added to ethanoic acid.
(ii) solid sodium carbonate is added to ethanoic acid.
(iii) ethanoic acid reacts with a dilute solution of sodium hydroxide.
Answer.
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Question.34 Describe two examples of different oxidations of ethanol. Name the products obtained in each case.
Answer.
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Question.35  Write a chemical equation in each case to represent the following types of chemical reactions of organic compounds:
(i) Oxidation reactions
(ii) Addition reactions
(iii) Substitution reactions
Answer.
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LONG ANSWER TYPE QUESTIONS [5 Marks] – Year 2011

Question.36 (a) In tabular form, differentiate between ethanol and ethanoic acid under the following heads:
(i) Physical state (ii) Taste
(iii) NaHCO₃ test (iV) Ester test
(b) Write a chemical reaction to show the dehydration of ethanol.
Answer. 
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Question.37 (a) State two properties of carbon which lead to a very large number of carbon compounds.
(b) Why does micelle formation take place when soap is added to water? Why are micelles not formed when soap is added to ethanol?
Answer.
(a) (i)-Catenation (ii) Tetravalency
(b) It is because large number of molecular ions of soaps get aggregated and form colloidal solution. Soap has hydrophobic tail (hydrocarbon) which dissolves in hydrocarbon part and hydrophilic part dissolves in water. Ethanol is non-polar solvent therefore micelles are not formed because hydrocarbon part gets attracted towards ethanol and ionic end will not dissolve in alcohol.

Question.38 Explain isomerism. State any four characteristics of isomers. Draw the structures of possible isomers of butane, C₄H₁₀
Answer. Isomerism is a phenomenon due to which some compounds have same molecular formula but different structural formulae.
Characteristics:
(i) They differ in structural formula.
(ii) They differ in melting point.
(iii) They differ in boiling point.
(iv) They differ in solubility in same solvent.
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Question.39 Give reasons for the following:
(i)Element carbon forms compounds mainly by covalent bonding.
(ii)Diamond has a high melting point.
(iii)Graphite is a good conductor of electricity.
(iv)Acetylene bums with a sooty flame.
(v)Kerosene does not decolourise bromine water while cooking oils do.
Answer.
(i) It is because carbon has four valence electrons, it cannot gain or lose four electrons because high energy is needed. It can only share four electrons.
(ii) It is due to strong covalent bonds and compact structure of diamond.
(iii) It is due to presence of free electrons in graphite because each carbon is linked to three more carbon atoms.
(iv) It is due to high percentage of carbon, it burns with sooty or smoky flame.
(v) Kerosene oil is mixture of saturated hydrocarbons therefore does not decolourise bromine water.

VERY SHORT ANSWER TYPE QUESTIONS [1 Mark] – Year 2012

Question.40 Name the functional group present in each of the following organic compounds:
(i) C₂H₅CI
(ii) C₂H₅OH
Answer.
(i) (—Cl) Halogen (Chloro)
(ii) (—OH) Alcohol

Question.41 Name the functional group present in each of the following compounds:
(i) HCOOH
(ii) C₂H₅CHO
Answer.
(i) —COOH (Carboxylic acid)
(ii) —CHO (Aldehyde)

Question.42 Name the functional group present in each of the following organic compounds:
(i)CH₃COCH₃
(ii) C₂H₅COOH
Answer.
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Question.43 Write the name and formula of the second member of the carbon compounds having functional group —OH.
Answer.
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Question.44 Write the name and formula of the first member of the carbon compounds having functional group —CHO.
Answer.
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Question.45 Write the name and formula of the first member of the carbon compounds having functional group —COOH.
Answer.
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Question.46 Write the name and formula of the 2nd member of the series of carbon compounds whose general formula is C_nH_2n+1OH
Answer. Ethanol, C₂H₅OH or CH₃CH₂OH

Question.47 Write the name and formula of the 2nd member of the series of carbon compounds whose general formula is CnH_2n.
Answer.
C₃H_6, H₂C=CH—CH₃
Propene is second member of series whose general formula is C_nH_2n.

SHORT ANSWER TYPE QUESTIONS[II] [3 Marks] – Year 2012

Question.48 What are isomers? Draw the structures of two isomers of butane, C₄H₁₀. Why can’t we have isomers of first three members of alkane series?
Answer. Those compounds, which have same molecular formula but different structural formulae are called isomers.
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In first three members of alkane series, branching is not possible. Therefore, we cannot have isomers.

Question.49 Define homologous series of organic compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes.
Answer. The series of organic compounds having same functional group and similar chemical properties is called homologous series.
Each member differs from successive member by —CH₂— group. The difference in molecular weight between two successive members is 14 u.
Characteristics:
(i) It has same general formula, from which, all members can be derived.
(ii) They have similar chemical properties.
C₂H₄, CH₂=CH₂, Ethene is first member of alkene series.

Question.50 Complete the following equations:
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Answer.
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Question.51 Why homologous series of carbon compounds are so called? Write chemical formula of two consecutive members of a homologous series and state the part of these compounds that determines their
(i) physical properties, and (ii) chemical properties.
Answer. The series consists of members of same family with similar physical and chemical properties, therefore, called homologous series
(i) CH₃OH, and (ii) CH₃CH₂OH are two consecutive members of homologous series.
Alkyl group —CH₃ and —CH₃CH₂ part determines physical properties. Functional group —OH determines chemical properties of the compounds.

Question.52 Name the oxidising agent used for the conversion of ethanol to ethanoic acid. Distinguish between ethanol and ethanoic acid on the basis of (i) litmus test, (ii) reaction with sodium hydrogencarbonate.
Answer. Alkaline potassium permanganate or Acidified potassium dichromate.
(i)Ethanol will not affect litmus paper. Ethanoic acid will turn blue litmus ‘ paper red.
(ii) Ethanol will not react with sodium hydrogen carbonate. Ethanoic acid will give brisk effervescence due to colourless, odourless carbon dioxide gas.

Question.53 Distinguish between esterification and saponification reactions of organic compounds with the help of the chemical equation for each. What is the use of (i) esters and (ii) saponification process?
Answer.
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LONG ANSWER TYPE QUESTIONS [5 Marks] – Year 2012

Question.54 What is the difference between the chemical composition of soaps and detergents? State in brief the action of soaps in removing an oily spot from a shirt. Why are soaps not considered suitable for washing where water is hard?
Answer. oaps are sodium or potassium salts of fatty acids having — COONa group. Detergents are
sodium or potassium salts of sulphonic acids having — SO₃Na and — SO₄Na group. Cleansing action of soap: Soap molecules consist of a large hydrocarbon tail which is hydrophobic (water-hating or water repelling) with a negatively charged head which is hydrophilic (water-loving) as shown in figure.
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When a soap is dissolved in water, the molecules associate together as clusters called micelles in which water molecules, being polar in nature, surround the ions and the hydrocarbon part of the molecule attracts grease, oil and dirt.
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Question.55 List in tabular form three physical and two chemical properties on the basis of which ethanol and ethanoic acid can be differentiated
Answer.
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Question.56 What are the hydrocorbons write the name and general formula of (i) sturated hydrocarbons, (ii) unsaturated hydrocarbons, and draw the structure of one hydrocarbon of each type. How can an unsaturated hydrocarbon be made saturated?
Answer.
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Question.57 What are detergents chemically? List two merits and two demerits of using detergents for cleansing. State the reason for the suitability of detergents for washing, even in the case of water having calcium and magnesium ions.
Answer. Detergents chemically are sodium or potassium salts of sulphonic acid of benzene or alkene.
Merits:
(i) They work well with hard water.
(ii) They are more effective than soaps.
Demerits:
(i) They are expensive.
(ii) Some of them having branching are non-biodegradable, therefore create water pollution.
Detergents are suitable for hard water having  Mg²⁺ and Ca²⁺ ions because they do not form insoluble salts with Mg²⁺ and Ca²⁺ ions.

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Heredity  and Evolution Chapter Wise Important Questions Class 10 Science

VERY SHORT ANSWER TYPE QUESTION [1 Mark] -Year 2007

1. What is a gene? [Delhi]
Answer. Gene is the unit of inheritance. Gene is the part of a chromosome which controls the appearance of a set of hereditary characteristics.

SHORT ANSWER TYPE QUESTIONS [I] [2 Marks] -Year 2007

2. What is meant by analogous organs? Taking a suitable example, explain how they support the theory of Organic Evolution. [Delhi]
Answer. Analogous organs are those organs which I have different basic structural design and developmental origin but have similar appearance and perform similar functions.
Example: The wings of birds and bats look similar but have different design in their structure. They have a common function of flying but their origins are not common. So, birds and bats are not closely related.

3. What is a sex chromosome? [Foreign]
Answer. Sex chromosome is a chromosome that operates in the sex-determining mechanism of a species. Many animals have two different types of sex chromosomes. For example, in human there is a large X chromosome and a much smaller Y chromosome.

SHORT ANSWER TYPE QUESTIONS [II] [3 Marks] -Year 2007

4.Define ‘evolution’. Describe Darwin’s theory of evolution. [All India]
Answer. Evolution is the sequence of gradual changes which take place in the primitive organisms over millions of years and new species are produced. Since, the evolution is of the living organisms, so it is called ‘Organic Evolution’.
Darwin’s theory of Evolution: Charles Robert Darwin gave the theory of evolution in his famous book, ‘The Origin of Species’. The theory of evolution proposed by Darwin is known as ‘The Theory of Natural Selection’. It is also called ‘Darwinism’.
According to Darwin’s theory of evolution:

1. There is natural variation within any population and some individuals have more favourable variations than others.
2. Population remains fairly constant even though all species produce a large number of off springs.
3. This is due to ‘competition’ or struggle for existence between same and different species.
4. The struggle for survival within population eliminates the unfit individuals and those with ‘favourable variations’ survive and pass on these variations to their progeny to continue. This is called natural selection.
5. The favourable variations are accumulated over a long time period leading to the origin of a new species.

SHORT ANSWER TYPE QUESTIONS [I] [2 Marks] -Year 2008

5.”The sex of the children is determined by what they inherit from their father and not their mother.” Justify. [Delhi(C)]
Answer. It is because a child who inherits an X chromosome from her father will be a girl and one who inherits a Y chromosome from his father will be a boy. But all children inherit a X chromosome from their mother regardless of whether they are boys or girls.

6. Define variation in relation to a species. Why is variation beneficial to the species? [Delhi]
Answer. Variation refers to the differences in the characters or traits among the individuals of a species.
Variations are beneficial to the species because:

1. They enable the organisms to adapt themselves in changing environment.
2. Variations form the basis of heredity.
3. They form the raw materials for evolution and development of new species.

7. Describe briefly four ways in which individuals with a particular trait may increase in a population. [Foreign]
Answer. The four ways in which individuals with a particular trait may increase in a population are as follows:

1.  Sexual reproduction results into variations.
2. The individuals with special traits survive the attack of their predators and multiply while the other will perish.
3.  Genetic drift provides diversity without any adaptation.
4. Variations in the species may lead to increased survival of the individuals.

8. What are fossils? What do they tell us about the process of evolution? [All India(C): All India 2011]
Answer. The remains of dead plants and animals which were buried under the rocks millions of years ago are called fossils.
Fossils tell us about the process of evolution. The fossils of different organisms have some features similar to one species while some features are similar to the other species. In this way, they show the link between two species. They tell us that one species evolves from the other.

SHORT ANSWER TYPE QUESTIONS [II] [3 Marks] -Year 2009

9. Distinguish between acquired and inherited traits by giving one example of each. Why are traits acquired during the lifetime of an individual not inherited? [Delhi(C)]
Answer. Acquired trait is a particular characteristic that is developed during the lifetime of an individual. Such characteristics are not genetically controlled and cannot be passed on to the next generation. Example: Loss of weight due to starvation.
Inherited trait is the transmission of particular characteristics from parents to their off springs, generation to generation. Such traits are genetically determined characteristic that distinguishes a person.
Example: Colour of skin.
The acquired traits cannot change the DNA of the germ cells. Therefore, the acquired traits cannot be inherited over generations during the lifetime of an individual.

10. The human beings who look so different from each other in terms of colour, size and looks are said to belong to the same species. Why? Justify your answer. [All India(C)]
Answer. Human beings are said to belong to the same species because of the following reasons:

1. DNA studies.
2. Number of chromosome is same,
3. All have a common ancestor.
4. They interbreed among themselves to produce fertile young ones of their own kind.

SHORT ANSWER TYPE QUESTIONS [I] [2 Marks] -Year 2010

11. Give one example each of characters that are inherited and the ones that are acquired in humans. Mention the difference between the inherited and the acquired characters. [Delhi]
Answer. Eye colour or hair colour of a person is an example of inherited character whereas, body weight is an example of acquired character.
The basic difference between inherited and acquired character is that inherited character is passed on from parent to offspring and acquired characters are acquired by an individual during his lifetime depending upon his lifestyle.

SHORT ANSWER TYPE QUESTIONS [II] [3 Marks] -Year 2010

12. Explain the mechanism of sex determination in humans. [All India]
Or
With the help of a flow chart explain in brief how the sex of a newborn is genetically determined in human beings. Which of the two parents, the mother or the father, is responsible for determination of sex of a child? [Foreign]
Answer. Mechanism of Sex Determination in Human Beings:
In human beings, the sex of the individual is genetically determined.

• Sex determination is the process by which sex of a new born individual can be determined.
•  Human beings have 1 unpaired sex chromosome. Sex chromosome of male is XY and of female is XX.
•  Sex of a child depends on what happens at fertilisation.
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  Thus, father is responsible for the determination of the sex of a child.

13. With the help of suitable examples explain natural selection. [Foreign]
Answer. Let us assume that there exist a group of red beetles in some green bushes. Due to variation during sexual reproduction one green beetle evolved among them. This green beetle can pass the colour to its progeny which are green beetles.
Crows cannot see green beetles in green bushes and therefore, cannot eat them. The progeny of green beetles are not eaten while the progeny of red beetles continued to be eaten. As a result there are more and more green beetles in the beetle population. The progeny of green beetles increase due to natural selection which gives survival advantage.

SHORT ANSWER TYPE QUESTIONS [I] [2 Marks] -Year 2011

14. How is the equal genetic contribution of male and female parents ensured in the progeny? [Delhi]
Answer. During sexual reproduction, a female gamete or egg cell fuses with a male gamete or sperm cell which are haploid to form zygote. Zygote is diploid which contains 23 chromosomes from mother and 23 from father. In this way, an equal genetic contribution of male and female parents is ensured in the progeny.

15. What evidence do we have for the origin of life from inanimate matter? [All India]
Answer. Stanley L. Miller and Harold C. Urey provided evidence regarding origin of life from inanimate matter. They assembled an atmosphere similar to that existed on early earth. The atmosphere had molecules like ammonia, methane and hydrogen sulphide, but no oxygen and kept over water at temperature just below 100°C. Sparks were passed through the mixture of gases. At the end of a week, 15% carbon from methane had been converted to simple compounds of carbon like amino acids which make-up protein molecules. So, life arose afresh on earth.

SHORT ANSWER TYPE QUESTIONS [II] [3 Marks] -Year 2011

16. Explain the terms: (i) Speciation (ii) Natural selection [Delhi]
Answer. (i) Speciation is the evolution of reproductive isolation among once-interbreeding populations, i.e. the development of one or more species from an existing species.
(ii) Natural selection is the process, according to Darwin, which brings about the evolution of new species of animals and plants.

17. Explain with examples how the following are evidences in favour of evolution in organisms. (i) Homologous organs (ii) Analogous organs (iii) Fossils [Delhi]
Answer. (i) Forelimb of human and bird are homologous organs. They have same structural design and developmental origin but they have different functions and appearance. Homologous organs help us to understand that the organism has evolved from a common ancestor. The more common characteristics the two species have, the more closely they are related.
(ii) Analogous organs are those organs design and developmental origin but have similar appearance and perform similar functions.
Example: The wings of birds and bats look similar but have different design in their structure. They have a common function of flying but their origins are not common. So, birds and bats are not closely related.
(iii) Fossils and their study is useful in knowing about the species which are no longer alive. They provide evidence and missing links between two classes. They are helpful in forming a sequence of organisms in the pathway of evolution. Thus, fossils have an importance in deciding evolutionary relationship. Archaeopteryx is a fossil bird. It had feathers, fused bones and beak which are exclusively bird structures. It also had some features which are found in reptiles, e.g. teeth in jaw, claws on free fingers and a long tail. This fossil provides a clue that birds have evolved from reptiles.

18. Give an example of body characteristics used to determine how close two species are in terms of evolution and explain it. [All India]
Answer. Homologous organs help to identify the relationship between organisms. These characteristics in different organisms would be similar because they have inherited from a common ancestor. For example, forelimbs of human and wings of birds show closeness between the two species because the organs have similar basic structural design of limbs though it has been modified to perform different functions.

19. What are homologous organs? Can the wing of a butterfly and the wing of a bat be regarded as homologous? Why? [All India]
Answer. Homologous organs are those organs which have the same basic structural design and developmental origin but have different functions and appearance.
Example: The forelimb of a frog, a lizard, a bird and a man seem to be built from the same basic design of bones, but they perform different functions.
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No, the wing of a butterfly and the wing of a bat cannot be considered homologous organs because they have a common function for flying but their origin and structure are not common. So, they are analogous organs.

SHORT ANSWER TYPE QUESTIONS [II] [3 Marks] -Year 2012

20. What is meant by the term speciation? List four factors which could lead to speciation. [Delhi]
Answer. Speciation is the evolution of reproductive isolation among once interbreeding population.
Factors which can lead to speciation are:

1. Genetic drift: Over generations, genetic drift may accumulate which leads to speciation.
2. Natural selection: Natural selection may work differently in different location which may give rise to speciation.
3.  Severe DNA change.
4. A variation may occur which does not allow sexual act between two groups.

21. A blue colour flower plant denoted by BB is cross bred with that of white colour flower plant denoted by bb.
(a) State the colour of flower you would expect in their F₁  generation plants.
(b) What must be the percentage of white flower plants in F₂  generation if flowers of F₁ plants are self-pollinated?
(c) State the expected ratio of the genotypes BB and Bb in the F₂ progeny. [Delhi]
Answer.
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22. Distinguish between homologous organs and analogous organs. In which category ; would you place wings of a bird and wings of a bat? Justify your answer giving a suitable reason.[Delhi]
Answer.
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Wings of a bird and wings of a bat are analogous organs as they have different basic structural design but have similar appearance and perform similar functions.

23. Define the term ‘evolution’. “Evolution cannot be equated with progress”. Justify this statement. [Delhi]
Answer. Evolution is the sequence of gradual change which takes place in primitive organisms over millions of years and new organisms are formed. Evolution cannot be equated to progress from lower forms to higher forms. It seems to have given rise to more complex body designs even while the simpler body designs continue to flourish. For example, human beings have not evolved from chimpanzees, but both have common ancestor.

24. If we cross pure-bred tall (dominant) pea plant with pure-bred dwarf (recessive) pea plant we will get pea plants of F₁ generation. If we now self-cross the pea plant of F₂  generation, then we obtain pea plants of F₂  generation.
(a) What do the plants of F₂ generation look like?
(b) State the ratio of tall plants to dwarf plants in F₂ generation.
(c) State the type of plants not found in F₂ generation but appeared in F₂ generation, mentioning the reason for the same. [All India]
Answer. (a) All plants of F₁  generation will be tall plants.
(b) 3:1
(c) Dwarf trait is recessive trait which was not expressed in the F₁  generation, the recessive trait gets expressed in the F₂ generation after self pollination.

25. How are fossils formed? Describe, in brief, two methods of determining the age of fossils. [All India]
Answer. When organisms die, their bodies decompose due to action of micro organisms. However, sometime the body or at least some parts of the body may be in such an environment that does not let it decompose completely. All such preserved traces of living organisms are called fossils.
The age of fossils can be estimated by the following two methods:

1.  If we dig into the earth and start finding fossils, it can be assumed that the fossils closer to the surface are more recent to those found in deeper layers.
2. By detecting the ratios of different isotopes of the same element in the fossil material.

26. State the meaning of inherited traits and acquired traits. Which of the two is not passed on to the next generation? Explain with the help of an example.
Answer. Inherited traits are the characteristics transmitted from parents to their offspring.Acquired traits are characteristics which are developed during the lifetime of an individual.Acquired traits are not passed on to the next generation. For example, if we breed a group of mice, all their progeny will have tails. Now, if the tails of these mice are removed by surgery and allowed to breed, the next generation mice will also have tails. If these tails are also removed and allowed to breed, the progeny of mice will again have tails. Removal of tail by surgery is an acquired trait and do not change the genes of germ cells and hence, are not passed on to the next generation.

27.”An individual cannot pass on to its progeny the experiences of its lifetime.” Justify the statement with the help of an example and also give reason for the same. [Foreign]
Answer. Experience achieved during the lifetime of an individual does not make any change in the gene of the individual.
For example, if a person reads a book on birds, the knowledge he earns by reading the book does not make any change in the gene, hence, this knowledge will not get automatically transmitted to his next generation. Such a trait is called acquired trait.

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Human Eye and Colourful World Chapter Wise Important Questions Class 10 Science

LONG ANSWER TYPE QUESTION [5 Marks] – Year 2007

1. A 14-year old student is not able to see clearly the questions written on the blackboard placed at a distance of 5 m from him.
(a) Name the defect of vision he is suffering from.
(b) With the help of labelled ray diagrams show how this defect can be corrected.
(c) Name the type of lens used to correct this defect. [All India]
Answer.
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VERY SHORT ANSWER TYPE QUESTIONS [1 Mark] – Year 2008

2. Why is red colour selected for danger signal lights? [Delhi]
Answer. Wavelength of red colour is more and so, it is least scattered. It can be easily seen through a large distance.

3. Study the diagram given below and answer the questions that follow it:
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(a) Which defect of vision is represented in this case? Give reason for your answer.
(b) What could be the two causes of this defect?
(c) With the help of a diagram show how this defect can be corrected by the use of a suitable lens. [Delhi(C)]
Answer. (a) Hypermetropia as the image is formed beyond the retina.
(b) (i) Due to greater focal length of the , lens and
(ii) As eyeball becomes smaller.
(c) It can be corrected by using a convex lens of suitable focal length as shown below.
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SHORT ANSWER TYPE QUESTIONS [I] [2 Marks] – Year 2009

4. Student sitting at the back bench in a class is not able to see what is written on the blackboard. He however, sees it clearly when sitting on the front seat at an approximate distance of 1.5 m from the blackboard. Draw ray diagrams to illustrate the image formation of the blackboard when he is seated at the (i) back seat (ii) front seat. [All India (C)]
Answer. (i) When student is seated at the back seat.
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(ii) When student is seated at front seat.
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5. What is meant by spectrum of white light? How can we recombine the components of white light after a prism has separated them? Draw a diagram to illustrate it. [Foreign, All India (C)]
Answer. The coloured pattern VIBGYOR formed by a prism by splitting the incident white light is called a spectrum. By having two prisms, inverted to each other, one can recombine the light to get white light again.
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6. Explain why do the planets not twinkle but the stars twinkle. [Delhi (C); Delhi 2011]
Answer. Planets being of larger size can be taken as a collection of large number of point-sized objects/sources of light, which nullify the twinkling effect of each other.
Due to varying conditions of atmosphere, starlight undergoes multiple refraction and its path varying slightly while passing through the atmosphere. Therefore, the apparent position of star fluctuates and amount of light entering the eye changing continuously. The star sometimes appear brighter and some other time, it appears fainter. This causes twinkling of star.

LONG ANSWER TYPE QUESTIONS [5 Marks] – Year 2009

7. (a) What is dispersion of white light? What is the cause of such dispersion? Draw a diagram to show the dispersion of white light by a glass prism.
(b) A glass prism is able to produce a spectrum when white light passes through it but a glass slab does not produce any spectrum. Explain why is it so? [All India]
Answer. (a) The splitting up of white light into its constituent colours is called dispersion. The colour sequence is given by the acronym V I B G Y O R – Violet, Indigo, Blue, Green, Yellow, Orange and Red. This colour pattern is called a spectrum.
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Dispersion takes place because the speed of light of different colours through a glass prism is different and so, refractive index, therefore, each colour bends (refracts) through different angles with respect to incident ray as they pass through a prism. The red colour has maximum speed in glass prism. So, it is least deviated while the violet colour has minimum speed so its deviation is maximum. Thus, the ray of each colour emerges along different paths and becomes distinct.
(b) For dispersion, the two refracting surfaces must be inclined to each other as in case of prism. In rectangular glass slab, the refracting surfaces are parallel to each other. So, dispersion cannot occur. This is due to fact that the rectangular glass slab can be considered as equivalent of two identical prisms in inverted position placed in an inverted position with respect to each other. The deviation and dispersion produced by the second inverted prism is equal and opposite to that produced by the first prism.
Therefore, there will neither be dispersion, nor deviation, Le. second inverted prism recombines the , colour to give a white light parallel to the incident ray again and will undergo only lateral displacement. Hence, rectangular glass slab cannot produce any spectrum.

8. (a) Explain the following terms used in relation to defects in vision and correction provided by them:
(i) Myopia (ii) Astigmatism (iii) Bifocal lenses (iv) Far-sightedness.
(b) Why is the normal eye unable to focus on an object placed within 10 cm from the eye? [All India]
Answer. (a) (i) Myopia: Short-sightedness is caused due to excessive curvature in cornea or elongation of eyeball. Image is formed before of the retina. So, a concave lens is used to correct it.
(ii) Astigmatism: The inability to focus the light in both vertical and horizontal lines is called astigmatism. It is caused due to varying curvature in lens both horizontally and vertically. It is . corrected by using cylindrical lens.
(iii) Bifocal lenses: These are used to correct presbyopic eye. These contain lenses with upper concave and lower convex surface. Presbyopia arises with age.
(iv) Far-sightedness: Hypermetropia or far-sightedness is caused due to greater focal length of eye lens and/or when eyeball becomes smaller. Image is formed beyond the retina and can be corrected using a convex lens.
(b) The focal length of the lens cannot be changed up to an extent that objects nearer than 25 cm can be viewed (its near point is 25 cm). So it is not able to focus for 10 cm.

VERY SHORT ANSWER TYPE QUESTIONS [1 Mark] – Year 2010

9. Name the part of our eyes that helps us to focus near and distant objects in quick succession. [Delhi]
Answer. Ciliary muscles help in changing the focal length of the eye lens.

10. A person is advised to wear spectacles with concave lenses. What type of defect of vision is he suffering from? [All India]
Answer. Myopia or short-sightedness.

11. A person is advised to wear spectacles with convex lenses. What type of defect of vision is he suffering from? [All India]
Answer. Hypermetropia or far-sightedness.

12. Why do different components of white light deviate through different angles when passing through a triangular glass prism? [All India]
Answer. Due to change in refractive index offered by the medium.

13. A person can comfortably read a book but finds it difficult to read the number on a bus parked 5 m away from him. Name the type of defect of vision he is suffering from. Which type of lens should he use in his spectacles to correct his vision? [Foreign]
Answer. Myopia or short-sightedness. Concave lens should be used to correct his vision.

14. What will be the colour of the sky, when it is observed from a place in the absence of any atmosphere? Why? [All India; Delhi 2012}
Answer. Sky appears dark.
Reason: In the absence of atmosphere, there would have been no scattering of sunlight at all.

15. The sky appears dark instead of blue to an astronaut. State its reason. [Delhi; Delhi 2012]
Answer. The sky appears dark to the astronaut as scattering does not take place at very high altitude due to the absence of atmosphere.

SHORT ANSWER TYPE QUESTIONS [I] [2 Marks] – Year 2010

16. What is myopia (near-sightedness)? Draw a ray diagram to show how it can be corrected using a lens. [Delhi]
Answer. Myopia is the inability of an eye in viewing long distant objects. The image in this case is formed before the retina. For every myopic eye, there exists a far point beyond which clear image cannot be seen.
The short-sightedness is corrected by using a concave lens which diverges and shifts the image to the retina.
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17.What is hypermetropia (far-sighted-ness)? Draw a ray diagram to show how this defect can be corrected using a lens. [Delhi]
Answer. Hypermetropia is the inability of an eye in viewing the nearby objects. The image in this case is formed beyond the retina. For a hypermetropic eye, there exists a near point.
It is corrected by using a convex lens, which converges and shifts the image to the retina.
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18. Define the term dispersion of white light. State the colour which bends (i) the least and (ii) the most while passing through a glass prism. [All India; All India 2012]
Answer. The splitting up of white light into its component colours is called dispersion. The colour which bends (i) the least is red, and (ii) the most is violet, while passing / through a glass prism.

VERY SHORT ANSWER TYPE QUESTIONS [1 Mark] – Year 2011

19. What is Tyndall effect? [Delhi]
Answer. The phenomenon of scattering of light by the colloidal particles is called Tyndall effect.

20. Give an example of optical phenomena which occurs in nature due to atmospheric refraction. [Delhi]
Answer. Twinkling of stars.

21. Give an example of a phenomenon where Tyndall effect can be observed. [All India]
Answer. When a fine beam of sunlight enters a room containing suspended particles of dust, the path of the beam of light is visible. It is due to the scattering of light (Tyndall effect).

22. Name the type of particles which acts as a prism in the formation of rainbow in the sky. [All India]
Answer. Water droplets present in the atmosphere.

23. What is the cause of dispersion of white light on passing through a prism? [Foreign]
Answer. The refractive index of the material of a prism is different for different colours of light as different colours have different speeds in the material of a prism. Also, prism has non-parallel surfaces.

24. Name the atmospheric phenomenon due to which the sun can be seen above the horizon about two minutes before actual sunrise. [Foreign]
Answer. Atmospheric refraction.

SHORT ANSWER TYPE QUESTIONS [I] [2 Mark] – Year 2011

25. Give reasons:
(i) The extent of deviation of a ray of light on passing through a glass prism depends on its colour.
(ii) Lights of red colour are used for danger signals. [Foreign]
Answer. (i) Refractive index of a medium is different for different colours of light.
(ii) Due to large wavelength, red colour is least scattered and travel to large distance.

26. A star appears slightly higher (above) than its actual position in the sky. Illustrate it with the help of a labelled diagram. [Delhi; All India 2012]
Answer. The gradual change in the refractive index of different layers of the atmosphere due to the varying conditions of it causes atmospheric refraction. When starlight enters the atmosphere, it gets refracted continuously. The higher level of air acts as a rarer medium while the dense air near the surface of earth acts as a denser medium. So, the atmosphere bends the starlight towards the normal. As a result, the apparent position of star is slightly different from its actual position. Thus, star appears slightly higher (above) than its actual position in the sky.
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27 Draw a ray diagram to show the refraction of light through a glass prism. Mark on it (a) the incident ray. (b) the emergent ray and (c) the angle of deviation. [All India]
Answer. i-incident angle, r – refraction angle, δ – angle of deviation, e – angle of emergence.
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SHORT ANSWER TYPE QUESTIONS [II] [3 Mark] – Year 2011

28. (a) What is meant by the power of accommodation of an eye?
(b) A person with a myopic eye cannot see objects beyond 1.2 m directly. What should be the type of the corrective lens used? What would be its power? [All India]
Answer. (a) The maximum variation in power of the lens so that the far-off and nearby objects are viewed clearly is called power of accommodation.
(b) To correct, an object at infinity has to be brought as an image to 120 cm.
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A concave lens of focal length 120 cm and power – 0.83 D is to be used.

29. (a) What are the values of (i) near point and (ii) far point of vision of a normal adult person?
(b) A student has difficulty in reading the blackboard while sitting in the last row. What could be his defect of vision? Draw a ray diagram to illustrate this defect of vision. [All India]
Answer.
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30. Name the three common defects of vision. What are their causes? Name the type of lens used to correct each of them. [Foreign]
Answer. (i) Myopia:
Cause: Elongation of eyeball,
Type of lens used for correction: Concave lens of suitable power.
(ii) Hypermetropia:
Cause: Shrinking of eyeball,
Type of lens used for correction: Convex lens of suitable power.
(iii) Presbyopia:
Cause: Weakening of ciliary muscles,
Type of lens used for correction: Bifocal lens.

VERY SHORT ANSWER TYPE QUESTIONS [1 Mark] – Year 2012

31. Which phenomenon is responsible for making the path of light visible?[Delhi]
Answer. Tyndall effect.

32. State one function of iris in human eye. [All India]
Answer. Iris controls the size of pupil.

33. State one function of pupil in human eye. [All India]
Answer. Pupil regulates and controls the amount of light entering the eye.

34. State one role of ciliary muscles in the human eye. [All India]
Answer. Ciliary muscles help the eye lens to focus the image of an object on the retina by increasing or decreasing the curvature of eye lens.

35. State one function of the crystalline lens in the human eye. [Foreign]
Answer. Crystalline (eye) lens forms a real and inverted image of the object on the retina.

36. State two properties of the image formed by the eye lens on the retina.
Answer.

1. Image on the retina is real and inverted.
2.  Diminished in size.

37. State one function of cornea in human eye.
Answer. Cornea provides the refraction of light rays entering the eye.

38. Why does the sun appear reddish at sunrise?
Answer. At sunrise, the sun looks almost reddish because only red colour ( λb < λr ), which is least scattered is received by our eye and appears to come from the sun. Hence, the appearance of sun at sunrise, near the horizon may look almost reddish.

SHORT ANSWER TYPE QUESTIONS [I] [2 Mark] – Year 2012

39. A star sometimes appears brighter and some other times fainter. What is this effect called? State the reason for this effect. [Delhi]
Answer. This effect is called Twinkling effect.
Reason: It is due to atmospheric refraction of starlight. The atmosphere has varying layers. The gradual change in the refractive index of different layers of atmosphere causes atmospheric refraction and starlight undergoes multiple refraction. So, the fluctuation in the position of star occurs continuously due to the changing amount of light entering the eye. The star sometimes appears brighter and at some other times, it appears fainter. This causes twinkling of star.

40. What is the colour of the clear sky during day time? Give reason for it. [All India]
Answer. Clear sky appears blue.
Reason: When sunlight passes through the atmosphere having the molecules of air and other fine particles, whose size is smaller than the wavelength of visible light, these molecules and particles scatter the blue colour more strongly than the other colours of spectrum as the wavelength of blue colour is more. This scattered blue light enters our eye. So, the colour of sky appears blue to us during day time.

41. What is a spectrum? Why do different coloured rays deviate differently on passing through a glass prism? [All India]
Answer. The band of coloured component of a light beam is called its spectrum. The colour sequence is given by the acronym V I B G Y O R — Violet, Indigo, Blue, Green, Yellow, Orange and Red.
The speed of light of different colours in a medium like glass is different. Varying speeds for different colours lead to different refractive indices for different colours. It has been observed that the refractive index of glass for violet colour is more than that for red colour. All the colours present in white light refract through different angles and hence, emerge out from the prism with different directions and become distinct.

SHORT ANSWER TYPE QUESTION [II] [3 Mark] – Year 2012

42. What is meant by the term ‘power of accommodation’ of human eye? How does it help a person to see nearby as well as distant objects clearly.[Foreign]
Answer. The ability of eye lens to adjust its focal length to form the sharp image of the object at varying distances on the retina is called its power of accommodation.
When we see the nearby object, the ciliary muscles contract, it increases the thickness of eye lens. The eye lens then becomes thicker. As a result, the focal length of eye lens decreases in such a way that the clear sharp image of nearby object is formed on the retina. Thus, the object is seen clearly to us.
When we see the distant object, these muscles becomes relaxed, thus the eye lens becomes thinner, and consequently focal length of the lens increases. Therefore, the parallel rays coming from the distant object are focused on the retina and object is seen clearly to us. Thus, the accommodation power of an eye helps a person to see nearby as well as distant objects clearly.

LONG ANSWER TYPE QUESTION [5 Mark] – Year 2012

43. (a) A student cannot see clearly a chart hanging on a wall placed at a distance 3 m from his eye. Name the defect of vision he is suffering from. Draw a ray diagram to illustrate this defect. List its two possible causes.
(b) Draw a ray diagram to show how this defect may be corrected using a lens of appropriate focal length. [ Delhi]
(c) An eye donation camp is being organised by social workers in your locality. How and why would you help in this cause? [All India]
Answer. (a) Myopia or Short-sightedness is the inability of an eye in viewing long distance objects. The image in this case falls before the retina. For every myopic eye, there exists a far point beyond which clear image cannot be seen. Short-sightedness is caused due to
(i) excessive curvature in cornea. (ii) elongation of eyeball.
(b) The short-sightedness is corrected by using a concave lens which diverges and shifts the image to the retina.
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(c) Reasons for donating eyes:

1. A person’s corneal blindness can only be elevated by a human donor’s cornea.
2.  It is opportunity to restore someone’s sight.

Methods for supporting this cause:

1.  Make it a family tradition of donating the eyes.
2. Motivate and educating others about eye donation.
3.  Help removing all the myths . about eye donation.

Important QuestionsNCERT SolutionsSample PapersNCERT Exemplar Solutions

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How Do Organisms Reproduce?Chapter Wise Important Questions Class 10 Science

Important QuestionsNCERT SolutionsSample PapersNCERT Exemplar Solutions

SHORT ANSWER TYPE QUESTIONS [3 Marks] – Year 2007

Question. 1(i) What is fertilisation? Distinguish between external fertilisation and internal
fertilisation.
(ii) What is the site of fertilisation in human beings?
Answer.
(i) Fertilisation is defined as the fusion of a male gamete (sperm) with a female gamete (an ovum or egg) to form a zygote during sexual reproduction.
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(ii) The site of fertilisation in human beings is in the fallopian tube of female reproductive system.

Question.2 Define the terms unisexual and bisexual giving one example of each.
Answer. Unisexual is the plant whose flowers contain either stamens or carpels but not both. Example: Papaya, Watermelon.
Bisexual is the plant whose flowers contain both stamens and carpels. Example: Hibiscus, Mustard.

Question.3 Differentiate between ‘self-pollination’ and ‘cross-pollination’. Describe double fertilisation in plants.
Answer.
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During fertilisation in plants, the following events take place:
(i) One of the male gamete fuses with the female gamete present in the embryo sac.
(ii) The other male gamete fuses with the two polar nuclei in the embryo sac.
The first fusion product gives rise to the zygote while the second one forms the endosperm.
The process of two fusions occurring in the embryo sac is called double fertilisation.

VERY SHORT ANSWER TYPE QUESTION [1 Mark] – Year 2008

Question.4 What is the effect of DNA copying which is not perfectly accurate on the reproduction process?
Answer. DNA copying is not perfectly accurate and the resultant errors are a source of variations in populations of organisms.

SHORT ANSWER TYPE QUESTIONS [2 Marks] – Year 2008

Question.5 What is ‘reproduction’? Mention the importance of DNA copying inreproduction.
Answer. Reproduction is the process of producing new individuals of the same species
by existing organisms of a species, i.e. parents. The importance of DNA copying in reproduction are as follows:
(i) DNA copying is called DNA replication. In this process, one copy each of replicated DNA will be passed to daughter cells.
(ii) Variations may be introduced during DNA copying. This inbuilt tendency for variation during reproduction forms the basis of evolution.

Question.6 “Variations that confer an advantage to
an individual organism only will survive in a population.” Justify.
Answer. It is because the chances of survival depend on the nature of variations and different individuals have different kinds of advantages.
For example, a bacteria that can withstand heat will survive better in a heat wave, i.e. the organisms that are fit in the competitive environment and with great variations will be able to survive and adapt. Thus, more offsprings and population with genetic variations will survive.

Question.7 Name one sexually transmitted disease
each caused due to bacterial infection and viral infection. How can these be prevented?
Answer. Sexually transmitted disease caused due to
(i) Bacterial infection is gonorrhoea, and
(ii) Viral infection is AIDS (Acquired Immune Deficiency Syndrome). These diseases can be prevented by responsible sexual behaviour such as use of condom during intercourse, etc.

Question.8(a) In the human body what is the role of
(i) seminal vesicles, and (ii) prostate gland?
(b) List two functions performed by testis in human beings.
Answer. (a) The role of seminal vesicles and the prostate gland are as follows:
(i) Seminal vesicles produce seminal plasma which is in the form of fluid makes the transport of sperms smooth.
(ii) Prostate gland secretes prostatic fluid that keeps the sperms alive and helps them to swim vigorously.
(b) Two functions performed by testis
in human beings are as follows:
(i) Formation of sperms takes place in testis.
(ii) They secrete the hormone testosterone which regulates the formation of sperms and brings changes in appearance of boys at the time of puberty.

SHORT ANSWER TYPE QUESTK)NS[II] [3 Marks] – Year 2008

Question.9 Illustrate the following with the help of suitable diagrams:
(i) Regeneration in Planaria.
(ii) Budding in Hydra.
Answer.
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Question.10 Illustrate the following with the help of suitable diagrams:
(i) Binary Fission in Amoeba.
(ii)Leaf of Bryophyllum with buds.
Answer.
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Question.11 Illustrate the following with the help of suitable diagrams:
(i) Spore formation in Rhizopus.
(ii)Multiple fission in Plasmodium.
Answer.
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LONG ANSWER TYPE QUESTIONS [5 Marks] – Year 2008

Question.12 (a) Name the parts labelled A, B, C, D and E.
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(b) Where do the following functions occur?
(i) Production of an egg
(ii) Fertilisation
(iii) Implantation of zygote.
(c) What happens to the lining of uterus:
(i) before release of a fertilised egg?
(ii) if no fertilisation occurs?
Answer. (a)
A – Oviduct or Fallopian tube;
B – Ovary;
C – Uterus;
D – Cervix;
E – Vagina.
(b) (i) Ovaries; (ii) Fallopian tube;
(iii) Lining of the uterus.
(c) (i) The lining of uterus becomes
(ii) The lining of uterus slowly breaks and comes out through the vagina as blood and mucous, if no fertilisation occurs.

Question.13(a) Draw a diagram showing
germination of pollen on stigma of a flower.
(b) Label pollen grain, male germ- cells, pollen tube and female germ-cell in the above diagram.
(c) How is zygote formed?
Answer. (a) and (b)
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(c) Zygote is formed when male gamete, Le. sperm fuses with female gamete, i.e. ovum.

VERY SHORT ANSWER TYPE QUESTIONS [1 Mark] – Year 2009

Question.14 Mention the mode of reproduction used by
(a) Amoeba (b) Planaria.
Answer. Mode of reproduction used by
(a) Amoeba is Binary fission.
(b) Planaria is Regeneration.

Question.15 Name the information source of making proteins in the cell. State two basic events in reproduction.
Answer. The DNA in the cell nucleus is the information source of making proteins.
The two basic events in reproduction are:
(i) Creation of a DNA copy,
(ii) Additional cellular apparatus by the cell involved in the process.

Question.16 State the method used for growing rose
plants.
Answer. Artificial methods of vegetative propagation like cutting are used to grow rose plants.

Question.17 State what type of method is used for
growing jasmine plant.
Answer. Artificial methods of vegetative propagation like layering is used for growing jasmine plant.

Question.18 Name the largest cell present in the
human body.
Answer. The largest cell present in the human body is ovum.

SHORT ANSWER TYPE QUESTIONS [I] [2 Marks] – Year 2009

Question.19 What is regeneration? State a reason why a more complex organism cannot give rise to new individuals through this method.
Answer. Regeneration is the ability of a fully differentiated organism to give rise to new individual organisms from its body parts. More complex organisms cannot give rise to new individuals through regeneration because:
(i) their body is highly complicated.
(ii) there are specific organs to do specific functions.
(iii) there is a labour division in the body of complex organisms.
(iv) regeneration is carried out by specialised cells which are not present in complex organisms.

Question.20 What is reproduction? What are its two types? Which one of the two confers new characteristics on the offsprings and how?
Answer. Reproduction is the process of producing new individuals of the same species by existing organisms of a species, z.e. parents. Its two types are: Asexual reproduction and Sexual reproduction.
Sexual reproduction confers new characteristics on the offspring due to variation in DNA copying.

SHORT ANSWER TYPE QUESTIONS][II] [3 Marks] – Year 2009

Question.21(a) Explain the terms:
(i) Implantation (ii) Placenta
(b) What is the average duration of human pregnancy?
Answer. (a)
(i) Implantation: The embedding
of a fertilised mammalian egg (embryo) into the inner thick wall of the uterus (womb) where it will continue its development is called implantation.
(ii) Placenta: It is a complex double-layered spongy vascular tissue in human female formed by the joint activity of maternal and foetal tissues in the wall of uterus that is meant for attachment, nourishment and waste disposal for the foetus.
(b) The average duration of human pregnancy is 40 weeks or 280 days.

Question.22 What are sexually transmitted diseases?
Name four such diseases. Which one of them damages the immune system of human body?
Answer. Sexually Transmitted Diseases (STDs) are the diseases which are spread by sexual contact from an infected person to a healthy person. They are caused by various microorganisms that live in warm and moist environments of the vagina, urethra, anus and mouth.
The four sexually transmitted diseases are:
(i) Gonorrhoea
(ii) Syphilis
(iii) Trichomoniasis
(iv) AIDS (Acquired Immune Deficiency Syndrome).
AIDS damages the immune system of human body.

SHORT ANSWER TYPE QUESTION[I] [2 Marks] – Year 2010

Question.23 List any four reasons for vegetative propagation being practised in the growth of some type of plants.
Answer.
(i) Vegetative propagation is a cheaper, easier and more rapid method of propagation in plants than growing plants from their seeds.
(ii) Better quality of plants can be maintained by this method.
(iii) It results in propagation of those plants which do not produce viable seeds or produce seeds with prolonged period of dormancy.
(iv) The plants generated from vegetative means are more uniform and genetically similar to the parent stock.

SHORT ANSWER TYPE QUESTIONS][II] [3 Marks] – Year 2010

Question.24 Write the full form of DNA. Name the part of the cell where it is located. Explain its role in the process of reproduction of the cell.
Answer. The full form of DNA is deoxyribonucleic acid. It is the genetic material found in the chromosomes, which are present in the nucleus of a cell.
Role of DNA in the process of repro¬duction of the cell:
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DNA plays an important role in the reproduction of a cell. The reproducing cell produces an identical copy of DNA through some cellular mechanism. Since the newly formed copy of DNA lacks an organised cellular structure, the cell gets divided to provide cell cover to the newly formed DNA. Thus, two daughter cells are formed from the single cell as a result of the copying of DNA.

Question.25 Explain vegetative propagation with the help of two examples. List two advantages of vegetative propagation.
Answer. In vegetative propagation, new plants are obtained from the parts of old plants like stems, roots and leaves, without the help of any reproductive organ.
There are two ways of vegetative propagation:
(a) Natural Vegetative Propagation, and
(b) Artificial Vegetative Propagation.
Natural vegetative propagation by leaves: The fleshy leaves of Bryophyllum bear adventitious buds in the notches along the leaf margin.
Grafting: In this method of reproduction, two plants of closely related varieties are joined together so that they live as one plant.

• The portion of a plant that is grafted on the other plant is called scion, and the plant in which grafting is performed is called the stock.
• This method is applied to improve variety of fruits like mango, apple, peas, citrus and guava.
  advantages of vegetative propagation are:

(i) Vegetative propagation is a cheaper, easier and more rapid method of propagation in plants than growing plants from their seeds.
(ii) Better quality of the plants can be maintained by this method.

Question.26 List any three differences between pollination and fertilisation.
Answer.
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LONG ANSWER TYPE QUESTIONS [5 Marks] – Year 2010

Question.27 Draw a longitudinal section of a flower and label the following parts:
(i) Part that produces pollen grain.
(ii)Part that transfers male gametes to the female gametes.
(iii) Part that is sticky to trap the pollen grain.
(iv) Part that develops into a fruit.
Answer.
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Question.28 (a) Explain the role of placenta in the
development of human embryo.
(b) Give example of two bacterial and two viral sexually transmitted diseases. Name the most effective contraceptive which prevents spread of such diseases.
Answer.
(a) Role of placenta in the development of human embryo: A special tissue develops between the uterine wall and the embryo (foetus) called placenta, where exchange of nutrients, glucose and oxygen takes place. The developing embryo will also generate waste substances which can be removed by transferring them into the mother’s blood through the placenta. The development of the child inside the mother’s blood takes approximately nine months.
(b) Sexually transmitted diseases (STDs) transmitted by bacteria are:
(i) Gonorrhoea (ii) Syphilis
STDs transmitted by virus:
(i) AIDS (ii) Genital warts
The most effective contraceptive which prevents the spread of these diseases is by the use of mechanical barriers such as physical devices like condoms.

SHORT ANSWER TYPE QUESTIONS [I] [2 Marks] – Year 2011

Question.29 Write any two differences between binary fission and multiple fission in a tabular form as observed in cells of organisms.
Answer.
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Question.30 List any four modes of asexual reproduction.
Answer. Four modes of asexual reproduction are—Binary fission in Amoeba, Fragmentation in Spirogyra, Regeneration in Planaria and Budding in Hydra.

Question.31 Why is DNA copying an essential part of the process of reproduction?
Answer.DNA copying is an essential part of the process of reproduction because:
(i) DNA copying provides cellular apparatus in the daughter cells.
(ii) DNA in daughter cells will be able to control the functioning of daughter cells.
(iii)DNA copies will retain the traits.

SHORT ANSWER TYPE QUESTIONS [II] [3 Marks] – Year 2011

Question.33 What does HIV stand for? Is AIDS an infectious disease? List any four modes of spreading AIDS.
Answer. HIV stands for Human Immunodeficiency Virus.
Yes, AIDS is an infectious disease.
Four modes of spreading AIDS are as follows:
(i) By having sexual contact with an infected person.
(ii) By the transfusion of blood from an infected person.
(iii) Through infected needles used for injection.
(iv) Through the placenta from the mother to child during pregnancy.

Question.34 Expand AIDS. List any four methods of prevention (control) of AIDS.
Answer. AIDS stands for Acquired Immune Deficiency Syndrome.
Four methods of prevention or control of AIDS are as follows:
(i) Use condom during sex.
(ii) Avoid sharing of needles.
(iii) Test blood for AIDS before transfusion.
(iv) Avoid sexual contact with unknown person.

Question.35 (a) List any four reasons for adopting contraceptive methods.
(b) If a woman is using Copper-T, will it help in protecting her from sexually transmitted diseases? Why? 
Answer. (a) Four reasons for adopting contra¬ceptive methods are:
(i) To increase the gap between, two children.
(ii)To prevent unwanted preg¬nancy.
(iii)To prevent transmission of STDs.
(iv)To control population growth. (b) If a woman is using a copper-T,
it will not help in protecting her from sexually transmitted diseases. Copper-T prevents only implantation in the uterus.

Question.36 Explain the following methods of contraception giving one example of each:
(i) Barrier method
(ii) Hormonal imbalance method
(iii) Surgical method.
Answer.
(i) Barrier Method: In this method, physical devices such as condoms, diaphragm and cervical caps are used. These devices prevent the entry of sperm in the female genital tract during copulation, thus acting ‘ as a barrier between them.
(ii) Hormonal Imbalance Method: In
this method, specific drugs are used by females, which are of two types: oral pills and vaginal pills.
Oral pills contain hormones which stop the ovaries from releasing ovum into the fallopian tube. These pills are also called oral contraceptives (OCs) which act by changing the hormonal balance of the body so that eggs are not released and fertilisation cannot occur. The use of Intrauterine Contraceptive Devices (IUCDs) prevents implantation in the uterus. This device is copper-T placed safely inside the uterus by a doctor or nurse.
(iii) Surgical Method: In this method, a small portion of vas deferens in male and the fallopian tube in ‘ female is surgically removed or tied. It is called vasectomy in males and tubectomy in females. In this case, if the vas deferens in male is blocked, sperm transfer will be prevented and if the fallopian tube in the female is blocked, the egg will not be able to reach the uterus, thus fertilisation will not take place.

LONG ANSWER TYPE QUESTIONS [5 Marks] – Year 2011

Question.37 (a) What is fragmentation in organism?
Name a multicell-ular organism which reproduces by this method.
(b) What is regeneration in organism? Describe regeneration in Planaria with the help of a suitable diagram.
Answer. (a) Fragmentation: Multicellular organisms with simple body organisation such as filamentous algae-Spirogyra breaks up into two or more small pieces or fragments upon maturation. These fragments grow into new individuals.
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(b) Regeneration: It is the ability of a fully differentiated organism to give rise to new individual organisms from its body parts.

•  Small cut or broken parts of the organism body grow or regenerate into separate individuals.
•  Planaria can be cut into any number of pieces and each piece grows into a complete organism.
• Regeneration is carried out by specialised cells which proliferate and make large number of cells thus, undergoing changes to become various cell types and tissues.
• The changes taking place in an organised sequence is development.
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Question.38 With the help of suitable diagrams, explain the various steps of budding in Hydra.
Answer.

• Hydra reproduces by budding using the regenerative cells.
• A bud develops as an outgrowth in Hydra due to repeated cell division at one specific site.
•  When fully matures, the bud detaches itself from the parent body and develops into new indipendent individuals
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Question.39 (a) What is spore formation?
(b) Draw a diagram showing spore formation in Rhizopus.
(c) List two advantages for organisms
to reproduce themselves through spores.
Answer.
(a) When a slice of bread is kept in moist dark place for a few days, spores of Rhizopus present in air settle on the bread to form new fungus plants of Rhizopus.
(b) The Rhizopus consists of fine thread-like projections called hyphae. It has a knob like structure which is involved in reproduction called sporangia, containing spores, that develop into new Rhizopus.
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(c) Two advantages for organisms to reproduce themselves through spores are as follows:
(i) It is a faster mode of reproduc-tion.
(ii) Offsprings produced are identical.

SHORT ANSWER TYPE QUEST10NS[I] [2 Marks] – Year 2012

Question.40 State one genetically different feature between sperms and eggs of humans. What is its consequence?
Answer. The sex chromosome of human male is XY. A sperm of human male carries either an X chromosome or one Y chromosome.
The sex chromosome of human female is XX and hence, the egg always carries the X chromosome.
If a sperm carrying X chromosome fertilises an egg which carries X chromosome, then the’ child born will be a girl. If a sperm
carrying Y chromosome fertilises an egg which carries X chromosome, then the child born will be a boy.

Question.41 List two advantages of vegetative reproduction practised in case of an orange plant.
Answer. Two advantages of practising vegetative reproduction in orange plants are:
(i) The oranges produced are similar in size and shape.
(ii) Many oranges do not produce viable seeds and hence, vegetative method is good alternative.

Question.42 How does growing embryo get nutrition from the mother’s blood?
Answer. The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. This is a disc which is embedded in the uterine wall and transfers glucose and oxygen from the mother to the embryo.

Question.43 Define the term puberty. List two changes observed in girls at the time of puberty.
Answer. The period, when the rate of general body growth begins to slow down and reproductive tissues begin to mature, is called puberty.
Two changes observed in girls at the time of puberty are:
(i) The breast size begin to increase, (ii) Menstruation starts.

Question.44 What is meant by asexual reproduction? List its any two different forms.
Answer. Asexual reproduction is the process of producing new organism from a single parent without the involvement of sex cells. Fission and fragmentation are two different forms of asexual reproduction.

Question.45 Name an organism which reproduces by spore formation. List three conditions
favourable for spores to germinate and grow.
Answer. Rhizopus reproduces by spore formation. Conditions favourable for spore formation are:
(i) Cool place, (ii) Moist place and (iii) Dark place.

Question.46 “DNA copies generated during reproduction will be similar but may not be identical to the original.” Justify this statement.
Answer. DNA copies generated will be similar, but may not be identical to the original as some variations are so drastic that new DNA copy cannot work with the cellular apparatus it inherits. Such a newborn cell will simply die. Therefore, there could be many other variations in the DNA copies that would not lead to such a drastic outcome. Thus, the surviving cells are similar but slightly different from each other. This tendency of variation during reproduction is the basis for evolution.

Question.47 List two advantages of practising vegetative propagation in plants. Select two plants raised by this method from the list given below:
Banana, Gram, Pea, Rose, Tomato, Wheat.
Answer. Advantages of vegetative propagation are:

1. Plants raised by vegetative propa-gation can bear fruits and flowers earlier.
2.  Plants produced are genetically similar.
   Banana and Rose can be raised by vegetative method.

Question.48 List the parts of human male reproductive system which contribute fluid to the semen. State two advantages semen offers to the sperms.
Answer. Prostate glands and seminal vesicles add fluid in the vas deferens. This makes transportation of sperms easier and also provides nutrition to the sperms.

Question.49 Name the two types of germ-cells
present in human beings. How do they structurally differ from each other? Give two differences.
Answer. The two types of germ-cells present in human beings are sperm and ova. The sperm of human have either X or Y chromosome. The ova always carry X chromosome. The sperm is structurally long with a tail. The ova is round in structure.

SHORT ANSWER TYPE QUESTIONS[II] [3 Marks] – Year 2012

Question.50 List and explain in brief three methods of contraception.
Answer. Methods of contraception are:

1. Use of condom for penis or for vagina as a mechanical barrier for the sperms to reach the egg.
2.  Use of oral pills which change the hormonal balance so that eggs are not released.
3.  Surgical method where either the vas deferens of male is blocked or the fallopian tube of female is blocked.

Question.51 What is AIDS? Which microbe is responsible for AIDS infection? State one mode of transmission of this disease. Explain in brief one measure for the prevention of AIDS.
Answer. AIDS is the Acquired Immune Deficiency Syndrome.
It is caused by a virus called Human Immunodeficiency Virus.
AIDS is transmitted by sexual contact with an infected person.
AIDS can be prevented by avoiding sexual contact with infected person or by using condom during sex.

LONG ANSWER TYPE QUESTIONS [5 Marks] – Year 2012

Question.52 Describe in brief the role of (i) testis (ii) seminal vesicle, (iii) vas deferens, (iv) ureter and (v) prostate gland in human male reproductive system.
Answer.

1. Testis: Testes are oval shaped primary reproductive organs in men. The function of testes is to produce sperms and male sex hormone testosterone. The scrotum provides optimal temperature for the formation of sperms.
2.  Seminal vesicle: Seminal vesicles are a pair of thin walled muscular elongated sac which secrete fluid for nourishment of sperms.
3. vas deferens: The sperms are carried by a long tube called vas deferens to organs called seminal vesicles where the sperms get nourishment and stored.
4. Ureter It is the tube that carries urine from kidney to the urinary bladder. In humans, there are two ureters, one attached to each kidney.
5.  Prostate glands: Prostate glands produce a fluid which is released in the urethra along with secretion of seminal vesicles for nourishment and transportation of sperms.

Question.53 Draw a diagram of a human female reproductive system and label the part
(i) that produces egg
(ii) where fusion of egg and sperm take place
(iii) where zygote is implanted
What happens to human egg when it is not fertilised?
Answer.
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If the egg is not fertilised, the thick and nourishing lining of the uterus breaks and comes out through vagina as blood and mucous.

Question.54 State in brief the changes that take place in a fertilised egg (zygote) till birth of the child in the human female reproductive system. What happens to the egg when it is not fertilised?
Answer. The egg gets fertilised in the oviduct. The fertilised egg, the zygote gets implanted in the lining of the uterus and starts dividing. The uterus prepares itself every month to receive and nurture the growing embryo. The lining thickens and is richly supplied with blood to nourish the growing embryo.
The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. The development of the child inside the mother’s body takes approximately nine months. On completion of 9 months, the child is born as a result of rhythmic contractions of the muscles in the uterus.
If the egg is not fertilised, the thick and nourishing lining of the uterus breaks and comes out through vagina as blood and mucous.

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Maharashtra Board  Class 10 Solutions for Marathi कुमारभारती – हत्तीचा दुष्टान्त

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Maharashtra Board SSC Class 10 Solutions for Marathi कुमारभारती

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Maharashtra Board  Class 10 Solutions for Marathi कुमारभारती – मीच तुमचा बाजीराव

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Maharashtra Board SSC Class 10 Solutions for Marathi कुमारभारती

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Maharashtra Board  Class 10 Solutions for Marathi कुमारभारती – स्त्रीपुरुष तुलना

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Maharashtra Board SSC Class 10 Solutions for Marathi कुमारभारती

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NCERT solutions for class 8 Sanskrit सुभाषितानि

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NCERT solutions for class 8 Sanskrit

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Ultimate Book of Accountancy Class 12 Part A Solutions – Goodwill

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Practical Problems

Solution 1:
Average Profit = 8,000 + 10,000 + 14,000 + 12,000 = 44,000/4 = 11,000
Goodwill = 11,000 × 2 = 22,000

Solution 2:
Average Profit = 6,000 – 4,000 – 2,000 + 8,000 + 12,000 = 20,000/5 = 4,000
Goodwill = 4,000 × 2.5 = 10,000

Solution 3:
Average Profit = 20,000 + 20,000 + 40,000 + 20,000 = 1,00,000/4 = 25,000
Goodwill = 25,000 × 1.5 = 37,500

Solution 4:
Average Profit = 20,000 + 40,000 + 40,000 + 20,000 + 30,000 = 1,50,000/5 = 30,000
Goodwill = 30,000 × 2 = 60,000

Solution 5:
Average Profit = 50,000 + 60,000 + 70,000 = 1,80,000/3 = 60,000 – 36,000 = 24,000
Goodwill = 24,000 × 2 = 48,000

Solution 6:
Average Profit = 45,000(60,000 – 15,000) + 1,50,000 (1,20,000 + 30,000) + 1,05,000 (1,14,000 – 9,000) = 3,00,000/3 = 1,00,000
Goodwill = 1,00,000 × 2 = 2,00,000

Solution 7:
Average Profit =
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Average Profit = 1,62,000/4 = 40,500
Goodwill = 40,500 × 2 = 81,000

Solution 8:
Calculation of Goodwill :

Weighted Average Profit = 6,00,000/15 = 40,000
Goodwill = 40,000 × 2.5 = 1,00,000

Solution 9:
Calculation of Goodwill :

Weighted Average Profit = 2,49,000/15 = 16,600
Goodwill = 16,600 × 2 = 33,200

Solution 10:
Calculation of Goodwill :
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Calculation of weighted average profits:

Weighted Average Profit = 1,09,640/10 = 10,964
Goodwill = 10,964 × 3 = 32,892

Solution 11:
Average Profit = 27,000 + 30,000 + 33,000 = 90,000/3 = 30,000
Normal Profit = Capital investment × 10/100 = 90,000 × 10/100 = 9,000
Super Profit = 30,000 – 9,000 = 21,000
Goodwill = 21,000 × 2 = 42,000

Solution 12:
Goodwill (given) = 48,000
Super Profit = 48,000/4 = 12,000
Normal Profit = 1,50,000 × 10/100 = 15,000
Super Profit = Average Profit – Normal Profit
12,000 = ? – 15,000
Average profit = 12,000 + 15,000 = 27,000

Solution 13:
Average Profit = 14,000 + 13,000 + 16,000 + 15,000 + 12,000 = 70,000/5 = 14,000
Normal Profit = 80,000 × 12/100 = 9,600
Super Profit = 14,000 – 9,600 = 4,400
Goodwill = 4,400 × 3 = 13,200

Solution 14:
Average Profit = 60,000 + 70,000 + 86,000 = 2,16,000/3 = 72,000
Remuneration = 72,000 – 12,000 = 60,000
Normal Profit = 4,00,000 × 10/100 = 40,000
Super Profit = 60,000 – 40,000 = 20,000
Goodwill = 20,000 × 2 = 40,000

Solution 15:
Average Profit = 12,200 + 15,000 – 2,000 + 21,000 = 46,200/4 = 11,550
Remuneration = 11,550 – 3,600 = 7,950
Normal Profit = 50,000 × 10/110 = 5,000
Super Profit = 7,950 – 5,000 = 2,950
Goodwill = 2,950 × 3 = 8,850

Solution 16:
Capitalised value of Average Profit = 20,000 × 100/10 = 2,00,000
Goodwill = 2,00,000 – 1,64,000 = 36,000

Solution 17:
Capialised value of Average Profit = 21,600 × 100/10 = 2,16,000
Net Assets = 3,00,000 – 90,000 – 1,20,000 = 1,71,000
Goodwill = 2,16,000 – 1,71,000 = 45,000

Solution 18:
Average Profit = 9,000
Normal Profit = 60,000 × 10/100 = 6,000
Super Profit = 9,000 – 6,000 = 3,000
Goodwill = 3,000 × 100/10 = 30,000

Solution 19:
Average Profit = 12,000
Normal Profit = 30,000 × 20/100 = 6,000
Super Profit = 12,000 – 6,000 = 6,000
Goodwill = 6,000 × 100/20 = 30,000

Solution 20:
Average Profit = 20,000 + 16,000 – 10,000 – 6,000 + 40,000 = 60,000/5 = 12,000
Remuneration = 12,000 – 4,000 = 8,000
Normal Profit = 50,000 × 10/100 = 5,000
Net Assets = 60,000 – 36,000 = 24,000
Case 1:
Goodwill by Average Profits = 8,000 × 2 = 16,000
Case 2:
Goodwill by Super Profit:
Super Profit = Average Profit – Normal Profit
8,000 – 5,000 = 3,000
Goodwill = 3,000 × 2.5 = 7,500
Case 3:
Capitalisation of Average Profit:
Capitalised value = 8,000 × 100/10 = 80,000
Goodwill = Capitalised value – Net Assets
56,000 = 80,000 – 24,000
Case 4:
Capitalisation of Super Profit:
Goodwill = Super Profit × 100/Rate = 3,000 × 100/10 = 30,000

Solution 21:
Average Profit = 72,000
Normal Profit = 1,87,500 + 1,50,000 + 1,12,500 = 4,50,000 × 10/100 = 45,000
Super Profit = 72,000 – 45,000 = 27,000
Goodwill = 27,000 × 100/10 = 2,70,000

Solution 22:
Average profit = 1,20,000 + 1,44,000 + 1,68,000 = 4,32,000/3 = 1,44,000
salary = 1,44,000 – 48,000 = 96,000
Normal Profit = 4,00,000 × 15/100 = 60,000
Super Profit = 96,000 – 60,000 = 36,000
Goodwill = 36,000 × 2 = 72,000
Note: Salary is 48,000 (24,000 each)

Brilliant Problems

Solution 1:
Case 1:
Average Profit = 1,47,600 + 1,48,100 + 1,52,500 = 4,48,200/3 = 1,49,400
Remuneration = 1,49,400 – 12,000 = 1,37,400
Goodwill = 1,37,400 × 3 = 4,12,200
Case 2:
Average profit = 1,37,400
Normal Profit = 7,00,000 × 18/100 = 1,26,000
Super Profit = Average Profit – Normal Profit
11,400 = 1,37,400 – 1,26,000
Goodwill = 11,400 × 3 = 34,200
Case 3:
Capitalisation of Average Profit = 1,37,400 × 100/18 = 7,63,333
Net Assets = 7,54,762 – 31,329 = 7,23,433
Goodwill = 7,63,333 – 7,23,433 = 39,900
Case 4:
Super Profit x 100/Rate = 11,400 × 100/18 = 63,333

Solution 2:
Average Profit = 32,280 + 36,870 + 43,350 = 1,12,500/3 = 37,500 – 1,800 = 35,700
Capital Employed = Total Assets (ignore non-trade investment) – outsiders liabilities = Creditors
2,42,040 – 30,000 – 38,040 = 1,74,000
Normal Profit = 1,74,000 × 10/100 = 17,400
Super Profit = 35,700 – 17,400 = 18,300
Goodwill = 18,300 × 2 = 36,600

Weighted Method:

Weighted Average Profit = 2,25,270/6 = 37,545
Normal Profit = 17,400
Super Profit = 37,545 – 17,400 = 20,145
Goodwill = 20,145 × 2 = 40,290

Solution 3:
Goodwill (given) = 24,000
Super Profit = 24,000/4 = 6,000
Normal Profit = 75,000 × 20/100 = 15,000
Super Profit = Average Profit – Normal Profit
6,000 = ? – 15,000
Average Profit = 6,000 + 15,000 = 21,000

Solution 4:
Goodwill = 18,000 (given)
Super Profit = 18,000/4 = 4,500
Capital Employed = 15,00,000 – 12,00,000 = 3,00,000
Normal Profit = 3,00,000 × 10/100 = 30,000
Average Profit = 30,000 + 4,500 = 34,500

Solution 5:
Average Profit = 45,000 + 60,000 + 63,000 (75,000 – 12,000) = 1,68,000/3 = 56,000
Normal Profit = 5,00,000 × 10/100 = 50,000
Super Profit = 56,000 – 50,000 = 6,000
Goodwill = 6,000 × 100/10 = 60,000

Solution 6:
Normal Profit = 10,00,000 × 20/100 = 2,00,000
Average Profit = 3,00,000 (given)
Super Profit = 3,00,000 – 2,00,000 = 1,00,000
Goodwill = 1,00,000 × 100/20 = 5,00,000
Goodwill = 1,00,000 × 2 = 2,00,000

Solution 7:
Capital employed = 20,00,000 – 3,60,000 = 16,40,000
Normal Profit = 16,40,000 × 10/100 = 1,64,000
Average Profit = 2,00,000
Super Profit = 2,00,000 – 1,64,000 = 36,000
Goodwill = 36,000 × 100/10 = 3,60,000
Goodwill = 36,000 × 3 = 1,08,000

Solution 8:
Average Profit = 1,56,800 + 1,40,000 + 1,80,000 + 1,20,000 = 5,96,800/4 = 1,49,200 – Remuneration (4,800 × 4) = 1,30,000
Normal Profit = 9,20,000 × 13/100 = 1,19,600
Super Profit = 1,30,000 – 1,19,600 = 10,400
Net Assets = 10,40,000 – 1,60,000 = 8,80,000
Goodwill by capitalisation of Average Profit = 1,30,000 × 100/13 = 10,00,000
10,00,000 – Net Assets 8,80,000 = 1,20,000
Goodwill by capitalising Super Profit = 10,400 × 100/13 = 80,000

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Ultimate Book of Accountancy Class 12 Part A Solutions – Basics of Partnership

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Practical Problems

Solution 1:
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Solution 2:
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Solution 3:
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Solution 4:
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Solution 5:
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Solution 6:
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Solution 7:
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Solution 8:
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Solution 9:
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Solution 10:
Case 1:
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Case 2:
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Case 3:
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Solution 11:
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Working Note:
Profit = 20,100 – 4,500 = 15,600
Out of which 12,000 divided as 50%, 30% and 20% and remaining 3,600 in equal ratio.
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Solution 12:
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Solution 13:
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Solution 14:
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Solution 15:
Case 1: Claim of B is not valid because partnership deed is silent on interest on partner’s loan. So he is entitled only for 6% p.a.
Case 2: Profit sharing ratio will be equal.

Solution 16:
(a) No salary will be given to any partner.
(b) No interest on capital to any partner. Only X will get 6% p.a. interest on loan.
(c) New partner can be admitted with the consent of old partners. In this case Y is objective, so X cannot admit his son as a partner.

Solution 17:
(a) No salary will be paid.
(b) No interest on capital will be given to any partner.
(c) Interest on partner’s loan will be 6% p.a.
(d) Profit sharing ratio will be equal
(e) No interest on drawings will be charged.

Solution 18:
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Solution 19:
Interest on M’s Loan (for 9 months) = 8,000 x 6/100 x 9/12 = 360

Solution 20:
Interest on A’s Loan = 15,000 x 6/100 x 6/12 = 450
Interest on B’s Loan = 15,000 x 6/100 x 6/12 = 450

Solution 21:
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Solution 22:
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Solution 23:
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Solution 24:
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Solution 25:
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Solution 26:
Interest on capital to B
Opening Capital = 8,000 + 3,000 (Drawings) – 1,000 (Profit)
Interest = 10,000 x 5/100 = 500
Note: Total profit was Rs.6,000 during the year out of which Rs.4,000 was kept aside and Rs.2,000 distributed by the partners in equally i.e. 1,000 each.

Solution 27:
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Solution 28:
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Solution 29:
Interest on John’s Capital = 2,00,000 x 5/100 = 10,000
Interest on Smith’s Capital = 2,00,000 x 5/100 = 10,000