  # Ray theory of light MCQ with answers

This sets of mcq's most includes objectives on ray theory of light, reflection of light, refraction of light and refraction index with answers for your preparation...

1. Light always travels at the same speed.
1. True
2. False

Ans – b

Explanation:- This statement is not true. There is conception that light always travels at the same speed. The speed of light depends upon the material or medium through which it is moving.

1. What is maximum possible speed of light in free space?
1. 170 × 103 miles/sec
2. 186 × 103 miles/sec
3. 177 × 103 miles/sec
4. 184 × 103 miles/sec

Ans – b

Explanation:- 186 × 103 miles/sec is the maximum possible speed of light in free space.

1. Which is two laws of light travels through a material?
1. Reflection, transparent
2. Refraction, transparent
3. Reflection, refraction
4. None

Ans – c

Explanation:- When light travels through a material it exhibits certain behavior explained by laws of reflection and laws of refraction.

1. The law of reflection of light is expresses as:
1. Angle of incident = angle of reflection
2. Angle of incident is not equal angle of reflection
3. Angle of incident is less than angle of reflection
4. Angle of incident is greater than angle of reflection

Ans – a

Explanation:- The law of reflection states that, when a light ray is incident upon a reflective surface at some incident angle Ø1 from imaginary perpendicular normal, the ray will be reflected from the surface at some angle Ø2 from normal which is equal to the angle of incidence.

Law of reflection is expresses as: The angle of incidence is equal to angle of reflection.

Ø1 = Ø2

1. What is law of refraction of light?
1. When light ray passes from one to another medium the light ray changes its direction at interface.
2. When light ray passes from one to another medium the ray reflect at same medium
3. Both
4. None

Ans – a

Explanation:- Law of refraction occurs when light ray passes from one medium to another medium i.e. the light ray changes its direction at interface. Refraction occurs when density of medium changes. E.g. refraction occurs at air and water interface, the straw in a glass of water will appear as it is bent.

1. The light wave or ray bent towards the normal this phenomena called as ___.
1. Reflection
2. Retraction
3. Refraction
4. None

Ans – c

Explanation:- When wave passes through less dense medium to more dense medium, the wave is refracted (bent) towards the normal. The refraction takes place because light travels at different speed in different mediums. The speed of light is higher than in water or glass.

1. Bending of light ray is called as ___.
1. Refraction
2. Reflection
3. Transparent
4. Retraction

Ans – a

Explanation:- Bending of light ray is called as refraction.

1. The amount of refraction or bending that occurs at the interface of two materials of different densities is usually expressed as ____.
1. Refraction law of light
2. Snell’s law
3. Reflection law of light
4. Refractive index of two materials

Ans – d

Explanation:- The amount of refraction or bending that occurs at the interface of two materials of different densities is usually expressed as Refractive index of two materials. Refractive index is also known as index of refraction.

1. Refractive index expressed as the ratio of:
1. Speed of light in air (C) / speed of light in medium (v)
2. speed of light in medium (v) / Speed of light in air (C)
3. None of above

Ans – a

Explanation:- Based on material density, the refractive index is expressed as the ratio of the velocity of light in free space to the velocity of light of the dielectric material.

N = c/v

1. The refractive index for vacuum and air is ___ for water it is ___ and for glass refractive index is ___.
1. 1.3, 1, 1
2. 1,1.5, 1.3
3. 1, 1.3, 1.5
4. 1, 1, 1

Ans – c

Explanation:- The refractive index for vacuum and air is 1 for water it is 1.3 and for glass refractive index is 1.5.

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