Question

A ray of light passes through equilateral prism such that the angle of incidence is equal to angle of emergence and each of these angles is equal to `(3/4)^"th"` the angle of prism. The angle of deviation is ______.

Options

• 35°

• 20°

• 40°

• 30°

Answer 1

A ray of light passes through equilateral prism such that the angle of incidence is equal to angle of emergence and each of these angles is equal to `(3/4)^"th"` the angle of prism. The angle of deviation is 30°.

Explanation:

`"i"=e=(3A)/4`

i + e = A + δ

δ = i + e - A =2i - A `=(3A)/2-A=A/2=30^circ`