Question

In a photo cell 4 unit photo electric current is flowing, the distance between source and cathode is 4 unit. Now
distance between source and cathode becomes 1 unit. What will be photo electric current now?​

Answer 1

Answer:

Since Current ∝ Intensity

And intensity is given by I = p/4πr^2 where p is the power of point source and r is the distance between source and cathode.

so,

i1/i2= ( r2/ r1)^2

4/i2= (1/4)^2

i2= 64 units