Class 8th Science Chapter 13 Light Questions Answers

Class 8 Science - Light

1. Can you see anything in a dark room? Why?

No, we cannot see objects in a dark room because there is no light. We need light to see things.

2. What is the difference between regular and diffused reflection?

Regular reflection happens on smooth surfaces; light reflects evenly. Diffused reflection happens on rough surfaces; light scatters.

3. Write whether regular or diffused reflection happens:

• Polished wooden table – Regular
• Chalk powder – Diffused
• Cardboard surface – Diffused
• Marble floor with water – Regular
• Mirror – Regular
• Piece of paper – Diffused

4. State the laws of reflection.

• The angle of incidence is equal to the angle of reflection.
• The incident ray, reflected ray, and the normal lie in the same plane.

5. Activity to show incident ray, reflected ray, and normal.

Shine a torch on a mirror placed on a table. Use chalk to trace the rays. You'll see all three rays in the same plane.

6. Fill in the blanks:

(a) A person in front of a plane mirror seems to be at the same distance behind the mirror.
(b) Touching your left ear with your right hand appears as touching right ear with left hand in the mirror.
(c) Pupil size becomes bigger in dim light.
(d) Night birds have more rods than cones.

7. Angle of incidence is equal to angle of reflection:

(a) Always ✅

8. Image formed by plane mirror is:

(b) virtual, behind the mirror and of the same size as the object ✅

9. Describe construction of a kaleidoscope.

It consists of 3 mirrors in a tube, placed at angles. Colored pieces at the end create beautiful patterns when you look through it.

10. Draw and label human eye.

Draw parts like: Cornea, Iris, Pupil, Lens, Retina, and Optic Nerve. Use arrows and labels for each part clearly.

11. Why was Paheli advised not to use a laser torch?

Laser light can harm the eyes. It is very strong and should not be used directly in any activity involving reflection.

12. How can you take care of your eyes?

• Don’t read in dim light.
• Wash your eyes with clean water.
• Avoid looking directly at bright light.

13. What is angle of incidence if angle of reflection is 90°?

It is not possible because angle of reflection and incidence must be equal. They cannot be more than 90°.

14. How many images formed by mirrors 40 cm apart?

When two mirrors are parallel, infinite images are formed. The distance does not stop the image formation.

15. Draw reflected ray from second mirror in Fig. 13.19.

Use a scale and protractor to draw an equal angle (30°) on the opposite side from the second mirror to show the reflected ray.

16. Can Boojo see himself and objects at P, Q, R?

Boojo cannot see himself or P. He may be able to see R depending on angle and distance. P is hidden by the mirror's edge.

17. Questions based on Fig. 13.21

(a) The image of A will be directly opposite A behind the mirror.
(b) Paheli can see the image if she is in front of it.
(c) Boojo cannot see the image from his side.
(d) Image of A moves right as Paheli moves from B to C.