A point light source is located at a distance L from a

Last updated: 6/8/2023

A point light source is located at a distance L from a screen A thir converging lens of focal length f L 4 and aperture radius R hel parallel to the screen makes a circular spot of light on the screen If len is moved from the source towards the screen size of the spot varies Fin the radius of the smallest light spot which can be obtained in this wa on the screen R FL 2VFL 2