A ray of light is incident on a `60^(@)` prism at the minimum deviation position. The angle of refraction at the first face (i.e. incident face) of the prism is-

Options

A. zero
B. `30^(@)`
C. `45^(@)`
D. `60^(@)`

Answer

2

Explanation

A = `r_(1) + r_(2)`
for deviation to be minimum
`r_(1)=r_(2)=r :.` A=2r
A=`60^(@) :. r=A/2=60^(@)/2 = 30^(@)`