NCERT Exemplar Class 8 Science Solutions for Chapter 16 - Light

NCERT Exemplar Class 8 Science Solutions for Chapter 16 - PDF Download Free Download

NCERT Exemplar solution for Class 8 Science Chapter 16 Light provide you necessary insights on the type and the level of difficulty of questions that are usually asked CBSE class 8 examination and few competitive examination. Hence it is very important for the students to get tuned-in with this NCERT Exemplar solution.

NCERT exemplar has variety of questions like multiple choice questions, match the following, fill-in the blanks, short answer questions, very short answer questions, long answer questions, numerical problems.

Light is an electromagnetic radiation within a certain portion of the electromagnetic spectrum. In this chapter, the students will learn about the different properties of light and their sources. Along with these, they will be introduced to the laws of reflection and how a human eye works or how does an eye see images. Solve and practice higher order thinking questions of this chapter from NCERT exemplar class 8 science chapter 16 light.

Download PDF of NCERT Exemplar Class 8 Science Solutions for Chapter 16 – Light

 

NCERT Exemplar solution class 8 science chapter 16 part 01
NCERT Exemplar solution class 8 science chapter 16 part 02
NCERT Exemplar solution class 8 science chapter 16 part 03
NCERT Exemplar solution class 8 science chapter 16 part 04
NCERT Exemplar solution class 8 science chapter 16 part 05
NCERT Exemplar solution class 8 science chapter 16 part 06
NCERT Exemplar solution class 8 science chapter 16 part 07
NCERT Exemplar solution class 8 science chapter 16 part 08
NCERT Exemplar solution class 8 science chapter 16 part 09
NCERT Exemplar solution class 8 science chapter 16 part 10
NCERT Exemplar solution class 8 science chapter 16 part 11
NCERT Exemplar solution class 8 science chapter 16 part 12

 

Access Answers of NCERT Exemplar Class 8 Science Solutions for Chapter 16 – Light

Multiple Choice Questions

1. Part of the eye which controls the light entering is called

(a) iris

(b) cornea

(c) lens

(d) retina

Soln:

Answer is (a) iris

Explanation:

Iris is a dark muscular structure exists behind the cornea. Its function is to control the entry of light.

2. We can see a non-luminous object when light:

(a) emitted by the object falls on the eye.

(b) is reflected from the object towards our eye.

(c) completely passes through the object.

(d) gets completely absorbed by the object.

Soln:

Answer is (b) is reflected from the object towards our eye.

3. Light is falling on surface S1, S2, S3 as shown in Fig.16.1.

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 1

Surfaces on which the angle of incidence is equal to the angle of reflection is/are

(a) S1 only

(b) S1 and S2 only

(c) S2 and S3

(d) all the three surfaces

Soln:

Answer is (d) all the three surfaces

Explanation:

Laws of reflection are always followed irrespective of the surface of the object hence angle of incidence is equal to angle of reflection.

4. A tiny mirror M is fixed on a piece of cardboard placed on a table. The cardboard is illuminated by light from a bulb. The position of eye with respect to position of bulb is shown in Fig.16.2 as A, B, C and D. In which position mirror will be visible?

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 2

a. A

b. B

c. C

d. D

Soln:

Answer is a. A

Explanation:

In case of A ray of light from A strikes mirror and gets reflected back to make angle of incidence and angle of reflection equal.

5. A small hole P is made in a piece of cardboard. The hole is illuminated by a torch as shown in Fig. 16.3. The pencil of light coming out of the hole falls on a mirror.

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 3

At which point should the eye be placed so that the hole can be seen?

(a) A

(b) B

(c) C

(d) D

Soln:

Answer is (a) A

Explanation:

Eye should be placed at position A because hole can be seen only when angle of incidence is equal to angle of reflection.

6. Two mirrors A and B are placed at right angles to each other as shown in Fig.16.4.

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 4

A ray of light incident on mirror A at an angle of 250 falls on mirror B after reflection. The angle of reflection for the ray reflected from mirror B would be

(a) 250

(b) 500

(c) 650

(d) 1150

Soln:

Answer is (c) 650

Explanation:

Angle of reflection for the ray reflected from mirror B will be 65° because reflected ray from mirror A forms incident ray on mirror 6 and then reflected back by an angle of 65°.

7. Which of the following statements is correct regarding rods and cones in the human eye?

(a) Cones are sensitive to dim light.

(b) Cones are sensitive to bright light.

(c) Rods are sensitive to bright light.

(d) Rods can sense colour.

Soln:

Answer is (b) Cones are sensitive to bright light.

Explanation:

Cones are sensitive to bright light hence they sense the color whereas rods are sensitive to dim light and they cannot sense color.

8. In the figure of the human eye (Fig.16.5), the cornea is represented by the letter

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 5

(a) A

(b) B

(c) C

(d) D

Soln:

Answer is (c) C

Explanation:

  1. Iris
  2. Lens
  3. Cornea

Very Short Answer Questions

9. Name the part of the eye which gives colour to the eyes

Soln:

IRIS the part of the eye which gives colour to the eyes.

10. Boojho while waving his hand very fast in front of his eyes, observes that his fingers appear blurred. What could be the reason for it?

Soln:

Persistence of vision

11. How many times is a ray of light reflected by two plane mirrors placed parallel and facing each other?

Soln:

Infinite number of times

12. The angle between incident ray and reflected ray is 60°. What is the value of angle of incidence?

Soln:

Answer is 30°.

Explanation:

Angle of reflection is equal to angle of incidence. Since Angle of incident ray+ Angle of reflected ray is 60°.

Angle of incidence = 30°

13. The distance between the object and its image formed by a plane mirror appears to be 24 cm. What is the distance between the mirror and the object?

Soln:

The distance will be 12 cm

Explanation:

Object +image formed =24 cm

Object +mirror =12 cm

Short Answer Questions

14. What happens to light when it gets dispersed? Give an example.

Soln:

When light gets dispersed it is split into its constituent colors. Ex: rainbow.

15. Draw Fig.16.6 showing the position of the plane mirror. Also label the angle of incidence and angle of reflection on it.

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 6

Soln:

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 7

16. Look at Fig.16.7. Can the image of the child in it be obtained on a screen?

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 8

Soln:

No, the image of the child cannot be obtained on a screen because image is a virtual image.

17. Eyes of the nocturnal birds have large cornea and a large pupil. How does this structure help them?

Soln:

They can see objects even in faint light. As large pupil and large cornea allows more light to enter their eyes.

18. What kind of lens is there in our eyes? Where does it form the image of an object?

Soln:

Our eyes has convex type of lens and the image is formed on the retina.

19. Which part of the eye gets affected if someone is suffering from cataract? How is it treated?

Soln:

If a person is suffering from cataract their eye lens will be cloudy. Cataract can be treated by replacing opaque lens by artificial lens.

Long Answer Questions

20. Boojho planned an activity to observe an object A through pipes as shown in Fig. 16.8, so that he could see objects which he could not directly see.

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 9

(a) How many mirrors should he use to see the objects?

(b) Indicate the positions of the mirrors in the figure.

(c) What must be the angle with respect to the incident light at which he should place the mirrors?

(d) Indicate the direction of rays in the figure.

(e) If any of the mirrors is removed, will he be able to see the objects?

Soln:

a) Three mirrors should he use to see the objects.

b)

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 10

c) 45°

d)

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 11

e) He will not be able to see the objects.

21. There is a mistake in each of the following ray diagrams given as Fig. 16.9 a, b, and c. Make the necessary correction (s).

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 12

Soln:

The Fig. in all the three cases after correction should be as in the given figure

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 13

22. Explain the process which enables us to perceive motion in a cartoon film.

Soln:

Carton movie is actually a projection of static picture. 24 pictures per second are shown in a specific order which give us the perception of movement.

23.How is the phenomenon of reflection used in making a kaleidoscope? What are the applications of a kaleidoscope?

Soln:

The kaleidoscope gives a number of images formed by reflection from the mirrors inclined to one another. Designers and artists use kaleidoscope to get ideas for new patterns to design wallpapers, Jewellery and fabrics.

24. Fig. 16.10 shows the word REST written in two ways in front of a mirror. Show how the word would appear in the mirror.

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 14

Soln:

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 15

25. Write down the names of parts of the eye in the blank spaces shown in Fig. 16.10.

NCERT Exemplar Class 8 Science chapter 16 Solutions fig 16

Soln:

1. Ciliary muscle

2. Iris

3. Lens

4. Cornea

5. Retina

6. Optic Nerve

NCERT Exemplar for class 8 Science Chapter 16 Light topics

  1. What makes Things Visible
  2. Laws of Reflection
  3. Regular and Diffused Reflection
  4. Reflected Light can be Reflected Again
  5. Multiple Images
  6. Sunlight – White or Coloured
  7. What is inside Our Eyes
  8. Care of the Eyes
  9. Visually Challenged Persons can Read and Write
  10. What is the Braille System?

 

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Frequently Asked Questions on Light

How is the phenomenon of reflection used in making a kaleidoscope? What are the applications of a kaleidoscope?

The kaleidoscope gives a number of images formed by reflection from the mirrors inclined to one another. Designers and artists use kaleidoscope to get ideas for new patterns to design wallpapers, Jewellery and fabrics.

Explain the process which enables us to perceive motion in a cartoon film.

Carton movie is actually a projection of static picture. 24 pictures per second are shown in a specific order which give us the perception of movement.

Which part of the eye gets affected if someone is suffering from cataract?

If a person is suffering from cataract their eye lens will be cloudy. Cataract can be treated by replacing opaque lens by artificial lens.

What kind of lens is there in our eyes ?

Our eyes has convex type of lens and the image is formed on the retina.

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