A Photocell is illuminated by a small bright source placed 1 m away. When the same source of light is placed $\frac{1}{2}m$ away, the number of electrons emitted by photocahode would :

Question

( A ) decrease by a factor of 4
( B ) increase by a factor of 4
( C ) increase by a factor of 2
( D ) decrease by a factor of 2