Question

Consider a prism made of glass of refractive index n and angle A = 30◦ as shown in the
figure. It is observed that a ray of light incident on the face P Q at angle θ = 60◦
emerges from
the face P R at 90◦
. Calculate the value of n. Square the number and multiply it by 4. Write
that number as answer.

Answer 1

Explanation:

Here, R.I. = n, A =30°,i = 60°, e = 90°, let

d = angle of deviation

We know that, d + A = i + e

or, d = ( 60°+ 90° )-30° = 120⁰

Also,

μ = [sin (A+d)/2] / sin A/2

Plugging in value in this formula you may

calculate the required refractive index.