#### Light Model Question Paper

8th Standard

Reg.No. :
•
•
•
•
•
•

Science

Time : 01:00:00 Hrs
Total Marks : 40
5 x 1 = 5
1. The spherical mirror with a reflecting surface curved inward is called

(a)

convex mirror

(b)

concave mirror

(c)

curved mirror

(d)

None of the above

2. If the focal length of a spherical mirror is 10 cm, what is the value of its radius of curvature?

(a)

10 cm

(b)

5 cm

(c)

20 cm

(d)

15 cm

3. Mirrors which magnify the object placed close to them.

(a)

Convex mirror

(b)

Concave mirror

(c)

Plane mirror

(d)

ellipsoid mirror

4. In which mirror the following statement is labeled?

(a)

Convex mirror

(b)

Concave mirror

(c)

Plane mirror

(d)

Spherical mirror

5. When the angle of inclination decreases the number of images formed _________

(a)

increase

(b)

decreases

(c)

remain same

(d)

none of the above

6. 5 x 2 = 10
7. Focal length of a spherical mirror is 7 cm. What is its radius of curvature?

8. If two plane mirrors are inclined to each other at an angle of 90°, find the number of images formed.

9. Refractive index of water is 4/3 and the refractive index of glass is 3/2. Find the refractive index of glass with respect to the refractive index of water.

10. What is the value of velocity of light in air?

11. When will the concave mirror form a real and inverted image?

12. 5 x 3 = 15
13. Define the refractive index of a medium.

14. State the Snell’s law of refraction

15. Tabulate the images formed by a convex mirror.

16. Name the rays which involved in reflection of light.

17. Why silver metal is used to make mirror?

18. 2 x 5 = 10
19. What is dispersion? Explain in detail.

20. What are the uses of convex mirrors?