Question

A point object O is placed midway between the concave mirrors, distance d apart. What is the value of d for which object and images coincide? Each mirror has focal length F –

• A. F, 2F
• B. 2F, 3F
• C. F, 4F
• D. 2F, 4F

Answer 1

Answer: (D)

2F, 4F

Answer 2

When $\frac { \mathrm { d } } { 2 }$ = F the rays from one mirror after reflection will reach parallel to the other mirror. Second mirror will refocus them at O when object is at 2F. Image is formed at 2F.