In photoelectric effect if we look at two different cross sections inside the tube at saturation current. Then the average drift velocity will be different as the electrons are accelerated by external battery.
So does this mean average current is different at different cross sections. According to me it (current) should remain the same at both cross section. But average drift speed is different. So by $$I=neAv_d$$ Either n should be different at different cross sections or i should be different. But if n is different is there any explanation why does electron density change.
Note:- I am assuming cross sectional area constant through the tube