A light ray incidents at an angle 'i' on a plane mirror and undergoes reflection. Arrange the following steps in sequential order to calculate the angle of deviation of the light ray.
(A) The angle between the incident ray and the extended light ray is `180^@` (B) In case of reflection, the angle of incidence (i) is equal to the angle of reflection (r). Then, the angle between the incident ray and the reflected ray is 2i. (C) Draw an imaginary line, extending the incident light ray, which represents the actual path of the light ray. (D) The angle of deviation is the angle between the reflected light ray and the actual path of the light ray, i.e., `180^@ - 2i`

Options

A. BADC
B. BCAD
C. BACD
D. CBDA

Answer

B

Explanation

In the case of reflection, the angle of incidence is equal to the angle of reflection. Then the angle between the incident light ray and the reflected light ray is equal to i + r. i.e., 2i. Draw an imaginary line extending the incident light ray which is the actual path of the light ray. The angle between the incident light ray and the actual path of the light ray is `180^@` . Then the angle of deviation is the angle between the reflected light ray and the actual path of the light ray, i.e., `180^@ - 2i` .