10th class Physics, Chapter 14: Light MCQs

1. What type of image is always formed by a convex mirror?

1. (A) Real and inverted
2. (B) Virtual and diminished ✓
3. (C) Real and magnified
4. (D) Virtual and magnified

2. The optical device which uses a convex lens to magnify an object by creating a virtual image:

1. (A) camera
2. (B) microscope
3. (C) magnifying glass ✓
4. (D) slide projector

3. Which statement best describes the phenomenon of total internal reflection?

1. (A) Light bends when it enters a new medium
2. (B) Light is completely reflected at the boundary of two media ✓
3. (C) Light slows down as it enters a denser medium
4. (D) Light passes through a medium without changing direction

4. A ray of light travelling from water to air bends:

1. (A) toward the normal
2. (B) away from the normal ✓
3. (C) at 90° to the normal
4. (D) parallel to the normal

5. The optical device which works on the principle of inverting an image for projection is:

1. (A) magnifying glass
2. (B) photograph enlarger
3. (C) slide projector ✓
4. (D) plane mirror

6. What happens to light when it enters an optical fibre?

1. (A) It is absorbed by the fibre
2. (B) It undergoes total internal reflection ✓
3. (C) It gets refracted at every point
4. (D) It travels in a straight line without deviation

7. Which of the following phenomenom explains why a pencil appears bent when partially immersed in water?

1. (A) Reflection
2. (B) Diffraction
3. (C) Refraction ✓
4. (D) Interference

8. According to the second law of reflection:

1. (A) angle of incidence = 90° − angle of reflection
2. (B) angle of reflection = 2 × angle of incidence
3. (C) angle of incidence > angle of reflection
4. (D) angle of incidence = angle of reflection ✓

9. Light reflected from a rough surface such as paper shows:

1. (A) dispersion
2. (B) diffused reflection ✓
3. (C) regular reflection
4. (D) total internal reflection

10. The normal at a point on a mirror is a line drawn:

1. (A) parallel to the surface
2. (B) along the incident ray
3. (C) along the reflected ray
4. (D) perpendicular to the surface ✓

11. The image formed by a plane mirror is:

1. (A) real, erect and magnified
2. (B) virtual, inverted and diminished
3. (C) real, inverted and of the same size
4. (D) virtual, erect and of the same size ✓

12. An object is placed 2 m in front of a plane mirror. The distance between the object and its image is:

1. (A) 2 m
2. (B) 1 m
3. (C) 8 m
4. (D) 4 m ✓

13. When light passes from air into glass it:

1. (A) does not bend
2. (B) is totally reflected
3. (C) bends towards the normal ✓
4. (D) bends away from the normal

14. In Snell's law, sin i / sin r is equal to the:

1. (A) speed of light c
2. (B) critical angle
3. (C) focal length f
4. (D) refractive index n ✓

15. The speed of light in vacuum is:

1. (A) 340 m s⁻¹
2. (B) 2.25 × 10⁸ m s⁻¹
3. (C) 3 × 10⁸ m s⁻¹ ✓
4. (D) 3 × 10⁶ m s⁻¹

16. The refractive index n of a medium is given by:

1. (A) c − v
2. (B) c / v ✓
3. (C) v / c
4. (D) c × v

17. The refractive index of a medium is always:

1. (A) equal to zero
2. (B) negative
3. (C) greater than or equal to 1 ✓
4. (D) less than 1

18. According to Table 14.1, which medium has the highest refractive index?

1. (A) Diamond ✓
2. (B) Crown glass
3. (C) Water
4. (D) Ice

19. The refractive index of water is:

1. (A) 2.42
2. (B) 1.00
3. (C) 1.33 ✓
4. (D) 1.52

20. The focus of a concave mirror is:

1. (A) virtual and in front of the mirror
2. (B) real and in front of the mirror ✓
3. (C) virtual and behind the mirror
4. (D) real and behind the mirror