Light Shadows and Reflections Class 7 Extra Questions and Answers Science Chapter 11

Students can keep Class 7 Science Extra Questions and Class 7th Curiosity Chapter 11 Light Shadows and Reflections Important Extra Question Answer handy for quick reference during exams.

Class 7 Science Chapter 11 Light Shadows and Reflections Extra Questions

Class 7 Science Chapter 11 Extra Questions on Light Shadows and Reflections

Light Shadows and Reflections Class 7 Very Short Question Answer

Question 1.
Where is the image formed by a plane mirror?
Answer:
Behind the mirror

Question 2.
How many mirrors are used in Periscope?
Answer:
Two mirrors.

Question 3.
How does the light travel?
Answer:
The light travels along straight line.

Question 4.
You have 3 opaque strips with very small holes of different shapes as shown in Fig. If you obtain an image of the Sun on a wall through these holes, will the image formed by these holes be the same or different?

Answer:
The image of the sun obtained will be same through all the three types of holes.

Question 5.
What is light?
Answer:
Light is a form of energy which helps us to see the objects.

Question 6.
Give one example of natural source of light.
Answer:
Sun is a natural source of light.

Question 7.
Three torches A, B and C shown in Fig. are switched on one by one. The light from which of the torches will not form a shadow of the ball on the screen.

Answer:
The torch at position C could not form an image of the ball on screen because to get an image on the source of light falling on the object must be opposite to the screen.

Question 8.
State the principle behind the working of a pinhole camera.
Answer:
Light travels in straight line.

Question 9.
Observe the picture given in Fig. A sheet of some material is placed at position ‘P’, still the patch of light is obtained on the screen. What is the type of material of this sheet?

Answer:
A sheet of transparent material must have been placed at position P due to which the light from the torch got reflected from mirror and the patch of the light could be obtained on the screen.

Question 10.
What types of objects do not cast shadows?
Answer:
Transparent objects do not cast shadows because light passes through them.

Light Shadows and Reflections Class 7 Short Question Answer

Question 1.
Why is the moon not considered as a luminous body?
Answer:
Moon is non-luminous body because it do not emit its own light rather reflectes the sunlight which falls on it.

Question 2.
Write the characteristics of image formed by a plane mirror.
Answer:
The characteristics of image formed by plane mirror:

1. The image formed is erect.
2. The image is laterally inverted.
3. The image is of same size as the object.
4. The image is formed at the same distance as object is placed from mirror.

Question 3.
You have to cast the shadow of your pencil on the wall with the help of candle in a dark room. How can you obtain the shadow of same size, small size and big size of the same pencil
Answer:

1. The shadow of the pencil will be small when the pencil is taken close to the wall and away from the candle.
2. The shadow will be big in size when the pencil is taken closer to the candle.
3. To get the same sized shadow as the pencil is, adjust the distance between the wall, pencil and candle at equal distances.

Question 4.
What is lateral inversion?
Answer:
When an image is formed by a mirror the left of the object appears on the right and the right appears on the left, this is known as lateral inversion.

Question 5.
What is the use of kaleidoscope?
Answer:
Designers of wallpapers, fabrics, artists use kaleidoscope to get ideas for new patterns. Q6. What are the essential conditions for the formation of shadow?
Answer:

1. There should be an opaque material.
2. There should be a source of light and screen.
3. The object must be placed in the path of light. Then only shadow is formed on the screen.

Question 7.
In Fig. a flower made of thick coloured paper has been pasted on the transparent glass sheet. What will be the shape and colour of shadow seen on the screen?
Answer:
The shadow formed will be a dark patch and the shape of the shadow will be the shape of the flower along with the stalk.

Question 8.
What is shadow? How does the colour of an opaque object affects the colour of the shadow?
Answer:
A dark outline or patch formed by an opaque object that blocks light coming from a source of light is called shadow. The colour of an opaque object does not affect the colour of the shadow.

Question 9.
A student covered a torch with red cellophane sheet to obtain red light. Using the red light she obtains a shadow of an opaque object. She repeats this activity with green and blue light. Will the colour of the light affect the Shadow? Explain.
Answer:
Changing the colour of light will not affect the shadow. This is due to the fact that shadow is a dark patch formed when the path of light is obstructed by an object which inhibits the light from reaching in the shadow region.

Question 10.
A and B are facing the mirror and standing in such a way that A can see B and B can see A. Explain this phenomenon

Answer:
Light from the surrounding environment illuminates both A and B, allowing them to reflect light. The light rays from A are directed toward the mirror, where they are reflected and then travel to B. Similarly, the light rays from B reach the mirror, are reflected, and finally travel to A. The paths of the light rays are reversed.

Light Shadows and Reflections Class 7 Long Question Answer

Question 1.
What is reflection of light? Explain reflection of light with the help of an activity.
Answer:
When light rays fall on a shiny surface or a mirror and it changes the direction of light that falls on it. This change in the direction of the light by a mirror or shiny surface is called reflection of light. Activity to show reflection of light: This activity should be done at night or in a dark room. Ask your friend to hold a mirror in his hand at one corner of the room. Stand at another corner with a torch in your hand. Cover the glass of torch with your fingers and switch it on. There should be small gap between your fingers. Direct the beam of torch-light on to the mirror that your friend is holding. Adjust the direction of torch so that patch of light falls on your friend standing in the room. This activity shows the reflection of light also that light travels in straight line.

Fig. A mirror reflects a beam of light

Question 2.
A sheet of plywood, a piece of muslin cloth and that of a transparent glass, all of the same size and shape were placed at A one by one in the arrangement shown in Fig. Will the shadow be formed in each case. If yes, how will the shadow on the screen be different in each case? Give reasons for your answer.
Answer:
The sheet of plywood will form a dark patched shadow on the screen because it completely obstructs the path of light. Whereas the piece of muslin cloth will form a lighter shadow because it allows light to pass through it partially. The transparent glass will allow the ray of light to pass through it and hence does not form any shadow.

Question 3.
With the help of an activity show that plane mirror forms laterally inverted image.
Answer:
Take a plane mirror. Stand in front of a plane mirror. Look at your image. Raise your left hand. It will find that in the mirror right appears left and left appears right. Such type of image is called laterally inverted. Now touch your right ear. It will appear right ear left and left ear in right side. Note that in this image only sides are interchanged but the image does not appear upside

Light Shadows and Reflections Class 7 Skill Based Questions

Question 1.
Observe the picture given below. What does the mirror reflect? What does this activity depict?

Answer:
A mirror reflects light that falls on it. Hence showing reflection of light.

Question 2.
Observe the diagram given below. What does the following activity depict?

Question 3.
What conclusion do you draw from this activity?
Answer:
Light travels in straight line and gets reflected from a mirror.

Light Shadows and Reflections Class 7 Case Based Question

Question 1.
Image Formation by Plane Mirror: Image formed by plane mirror has the following characteristics:
(i) Image is erect but laterally inverted,
(ii) Image retains the colour of the object,
(iii) Image is of same size as that of the object.

Lateral Inversion: The right side of object appears as left side in the image formed by plane mirror. The image changes its side. It means left-right inversion.

(i) In which type of mirror(s) lateral inversion can be seen?
Answer:
In plane mirror.

(ii) Define the type of lateral inversion from left-right view.
Answer:
It means left of an image is the right of the object.

(iii) If your height is 5 feet (5), then what will be the height of your image?
Answer:
It will be equal to 5 feet too.
OR
What is another name for lateral inversion?
Answer:
Left-right inversion.

Light Shadows and Reflections Class 7 Suggested Projects and Activities

1. Make a periscope using cardboard and two mirrors placed at 45° angles. Look through the periscope to see objects that are not directly in front of you. Observe how light reflects off the mirrors to reach your eyes.

2. Take a small piece of plane mirror and position it in front of a large object, like a building or a car, at a distance. Look into the mirror and observe the reflected image. Now, move the object closer to or farther away from the mirror, and notice how the size of the reflected image changes. Discuss how the position of the object affects the size of the image.

3. Take a piece of glass, frosted plastic, and cardboard. In a dark room, set up a light source (like a flashlight). Hold each object in front of the light source one by one and observe the shadows they form. Discuss whether each object forms a shadow.

Light Shadows and Reflections Extra Questions for Practice

Question 1.
Which of the following is a luminous object?
(a) Moon Light travels in a:
(b) Mirror
(c) Sun
(d) Book

Question 2.
Light travels in a:
(a) Curved path
(b) Wavy path
(c) Straight line
(d) Zigzag path

Question 3.
A periscope works on the principle of:
(a) Refraction
(b) Diffusion
(C) Reflection
(d) Absorption

Question 4.
Read the given statements and select the correct option.
Assertion (A): The image formed by a plane mirror is laterally inverted. Reason (R): A plane mirror reverses the left and right sides of the object.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Question 5.
Match the items in Column A with those in Column B.

(a) (i)-(p), (ii)-(q), (iii)-(r), (iv)-(s)
(b) (i)-(q), (ii)-(p), (m)-(r), (iv)-(s)
(c) (i)-(r), (ii)-(s), (iii)-(p), (iv)-(q)
(d) (i)-(s), (ii)-(r), (iii)-(q), (iv)-(p)

Question 6.
What type of image is formed on the screen by a pinhole camera?

Question 7.
Define shadow.

Question 8.
What do we call materials that allow some light to pass through?

Question 9.
Name one area where a periscope is used.

Question 10.
Give some examples of non-luminous objects.

Question 11.
Differentiate between luminous and non-luminous objects.

Question 12.
What do you mean by an opaque materials? Also give an example.

Question 13.
What is reflection of light?

Question 14.
What are the characteristics of a shadow?

Question 15.
What is a pinhole camera?

Question 16.
Describe how a shadow is formed.

Question 17.
How does light behave when it passes through different materials?

Question 18.
What is lateral inversion? Give one example where it can be seen.

Question 19.
Differentiate between transparent, translucent and opaque materials with one example each.

Question 20.
Write a short note on shadow puppetry.

Question 21.
Prove with a help of an activity that light travel in a straight line.

Question 22.
Briefly explain the following:
(a) Periscope
(b) Kaleidoscope
Also, mention two applications of each.

Question 23.
Describe the construction and working of a pinhole camera.

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