A light ray is made to incident on a mirror. If the glancing angle of incidence is `30^(@)`, then write the following steps in sequence to find the angle between the incident light ray and the reflected light ray.
(a) Note the glancing angle of incidence from the given information.
(b) The angle of reflection is equal to the angle of incidence.
(c) The angle of incidence `anglei` will be equal to `(90^(@)- 30^(@))`.
(d) The angle between the incident light ray and the reflected light ray is equal to `2 anglei` or `2(90^(@)-angle30^(@))`.

Options

A. DCAB
B. ADCB
C. DABC
D. ACBD

Answer

D

Explanation

Given that `angle g_(i)30^(@)`
The angle of incidence,
`angle i=90^(@)- angleg_(i)=90^(@)-30^(@)=60^(@)`
The angle of reflectio `angleg= anglei=60^(@)`
The angle between incident light ray and the reflected light ray is equal to
`2(i=2xx60^(@))=120^(@)`
Hence the correct option is (d).