Parallel beam of light incident normally on a wall

Last updated: 6/21/2023

Parallel beam of light incident normally on a wall illuminates a round spot of radius 4 0 cm on it When a ball surface of which is mirrored is placed with its centre on the axis of the beam and at a distance of 11 cm from the wall a large part of the wall is illuminated but at the centre a circular shadow of radius 52 cm is formed Find radius of the ball