Question:
A point source $S$ is placed midway between two converging mirror having equal focal length $f$ as shown in fig. Find the values od d for which only one image is formed.
Solution:
Both mirror produces one image in following two cases:
(A) When Source is at distance $=2 f$ or at center of curvature then image is produce at $v=2 f+2 f=4 f$
(B) When source is at distance $f$ then rays become parallel after reflecting through one mirror, then it is reflected through other mirror and only one image is formed
$V=f+f=2 f$