question_answer

In the figure shown a thin parallel beam of light is incident on a plane mirror \[{{m}_{1}}\] at small angle \['\theta '.\] \[{{m}_{2}}\] is a concave mirror of focal length \['f'\]. After three successive reflections of this beam the \[x\] and \[y\] coordinates of the image is

A) \[x=f-d,y=f\theta \]       

B) \[x=d+f,y=f\theta \]

C) \[x=f-d,y=-f\theta \]      

D) \[x=d-f,y=-f\theta \]

Correct Answer: D

Solution :

[d] Can be understood by the following ray diagrams: a Since, rays are almost perpendicular to P-axis Image will form at focus of size \[=f\theta \].