A ray of light passes through an equilateral glass prism in such a manner that the angle of incidence is equal to the angle of emergence and each of these angles is equal to 3/4 of the angle of the prism. The angle of deviation is

Options

A. `45^(@)`
B. `39^(@)`
C. `20^(@)`
D. `30^(@)`

Answer

D

Explanation

i= e = `(3)/(4) = (3)/(4) xx 60^(@) = 45^(@)`
Now, `delta_(m) = 2i - A rArr delta_(m) = 90^(@) - 60^(@) = 30^(@)` .