question_answer

If a concave mirror of focal length \[{{f}_{1}}\] is placed at a distance of d from a convex lens of focal length\[{{f}_{2}}\]. A light ray coming from infinity is falling on this combination and returns to infinity. The distance d must equal

A)  \[-{{f}_{1}}+{{f}_{2}}\]                    

B)  \[{{f}_{1}}+{{f}_{2}}\]

C)  \[-2\,{{f}_{1}}+{{f}_{2}}\]                 

D)  \[2\,{{f}_{1}}+{{f}_{2}}\]

Correct Answer: D

Solution :

The arrangement and ray diagram is shown in figure