Question

Question 2: A ray of light passing through air is incident on the surface of a

transparent material at an angle of incidence 30° . Which of the following statements

is correct if the angle of refraction is 50 °


a) The refractive index of the transparent material with respect to air is greater than 1.


b) The refractive index of the transparent material with respect to air is less than 1.


c) The angle by which the ray is deviated from its path is 40 °



d) The light-ray travels faster in the transparent material than in air.

And Why?​

Answer 1

Answer:

hii

Explanation:

When the ray of light are incident on the glass medium from air medium at 90° angle to the surface then the rays will move through without changing direction of motion. In this case, the angle of incidence and angle of refraction are remains zero. So, The angle of refraction is zero.

Answer 2

Answer:

b) The refractive index of the transparent material with respect to air is less than 1.

d) The light-ray travels faster in the transparent material than in the air.

Explanation:

Given,

Angle of incidence (i) = 30°

The angle of refraction (r) = 50°

To find,

The refractive index of the transparent medium.

Concept,

Snell's law

n₁ sin(i) = n₂sin(r)

Where n₁ = refractive index of medium 1

n₂ = refractive index of medium 2

i = incident angle

r = refracted angle

Calculation,

We know that the refractive index of air (n₁) = 1

And let the refractive index of the transparent medium be 'n₂'

Hence,

n₁ sin(i) = n₂sin(r)

1(sin30°) = n₂(sin50°)

n₂ = 0.5/0.766 = 0.6527

B) Now, the refractive index of the transparent medium with respect to air is

n₂₁ = n₂/n₁ = 0.65277 which is less than 1

Therefore, The refractive index of the transparent material with respect to air is less than 1.

C) And the angle of deviation is (r - i) = 50° - 30° = 20°

D) As in the transparent medium the refractive index is less than in air, the light travels faster in the transparent medium than in air.

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