A cesium photocell, with a steady potential difference of 60 V across it ,is illuminated by a small bright light placed 1m away. When the same light is placed 2m away, the electrons crossing the photocell

Options

A. each carry one-quarter of their previous momentum
B. each carry one-quarter of their previous energy
C. are one-quarter as numerous
D. are half as numerous

Answer

C

Explanation

`Iprop(1)/(d^2)`
When source is placed 2 m away, the `I'=((I)/(4))`. The number of electrons emitted `prop` intensity. Hence, the number of emitted electrons is reduced to one-fourth.