In an experiment on photoelectric effect, light of wavelength 400 nm is incident on a cesium plate at the rate of 5.0 W. The potential of the collector plate is made sufficiently positive with respect to the emitter so that the current reaches its saturation value. Assuming that on the average one out of every 106 photons is able to eject a photoelectron, find the photocurrent in the circuit.
Given, wavelength of light λ=400nm
Power P=5W
Energy of photon 
We know that, no. of electrons per second
It is given that on average one out of every 
Photons is emitted (i.e.; 1 per 
photons).
∴ No. of photoelectrons emitted =
∴ Photocurrent in the circuit =
=
1