question_answer

A plane mirror reflecting a ray of incident light is rotated through an angle \[\theta \] about an axis through the point of incidence in the plane of the mirror perpendicular to the plane of incidence, then                            [NCERT 1978; CPMT 1991]

A)            The reflected ray does not rotate

B)            The reflected ray rotates through an angle \[\theta \]

C)            The reflected ray rotates through an angle \[2\theta \]

D)            The incident ray is fixed

Correct Answer: C

Solution :

 By keeping the incident ray is fixed, if plane mirror rotates through an angle q reflected ray rotates through an angle 2q.