Question

Light is incident on one face of a glass block at an angle of incidence of 40°. The glass block is in air. The refractive index of the glass is 1.46.

What is the angle of refraction inside the glass block?
A 26° B 27° C 58° D 70°

Answer 1

Answer:

A. 26°

Explanation:

I will explain how I got it.

Initially, let's write out Snell's Law of Refraction.

n = sin i / sin r

"n" indicates refractive index

"i" indicates angle of incidence

"r" indicates angle of refraction

According to the question,

n = 1.46

i  = 40°

r  = ?

Now, let's substitute the given numbers into the equation. We'll get

1.46 = sin (40°) / sin (r)

If we multiply both sides by "sin (r)",

1.46 x sin (r) = sin (40°)

Therefore,

sin (r) = sin (40°) / 1.46

For "sin (40°)" , we get 0.6428

sin (r) = 0.6428 / 1.46

sin (r) = 0.4403

Now, multiply both sides with 1/sin , which can also be denoted as sin⁻¹

(r) = sin⁻¹ (0.4403)

(r) = 26.123

Therefore, rounding it off to the whole number, we get 26°.