Question

An object at a distance of 30 cm from a concave mirror gets its image at the same point. The focal length of the mirror is *

Answer 1

Answer:

Explanation:

Hope it's clear.

Answer 2

Explaination:image is formed same as object and in same place only when it is placed in radius of curvature.

Answer. Relation between radius of curvature and focal length is R=f/ 2. There fore focal length is 30/2= 15cm.