Question

A light ray falls on a rectangular glass slab as shown. The index of refraction of the glass, if total internal reflection is to occur at the vertical face, is
(a) $\sqrt{{3}/{2}}$(b) $\frac{(\sqrt{3}+1)}{2}$(c) $\frac{(\sqrt{2}+1)}{2}$(d) ${\sqrt{5}}/{2}$

Answer 1

Here is the answer to your question.

Sinc = 1/u

Answer 2

Answer:

a) √3/2

Explanation:

At point A = aμg = sin45°/ sinr = sinr = 1μ√2

At point B, the total internal reflection = sini1 = 1/μ

From the figure,  i1 =90°−r

Therefore, (sin 90°−r) = 1/μ

= cosr = 1/μ

= √2μ²−1/2μ²

1/μ =  √2μ²−1/2μ²

Squaring both sides and then solving, we get μ = √3/2

Thus, if the total internal reflection is to occur at the vertical face, is √3/2