Question

A lamp is 4.0m from a wall. Find the focal length of a concave mirror which will
form a five times magnified image of the lamp on the wall. How far from the
wall must the mirror be placed ?​

Answer 1

Answer:

Since it is a concave mirror, the image will be obtained on the screen i.e the wall. Therefore, the mirror should be placed 20 m away from the wall. Therefore, the focal length is 3.33 m.

Explanation:

hope it will help