In photo electric effect, the photo electric current

What is photoelectric effect? Why is photo electric current proportional to the intesity of incident radiation?

In photo electric effect, why should the photoelectric current increase as the intensity of monochromatic radiation incident on a photosensitive surface is increased? Explain .

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 ?

Why is wave theory of electromagnetic radiation not able to explain photo electric effect? How does photon picture resolve this problem ?

Distinguish between Photo voltaic effect & Photo electric effect.

Photo electric effect:-Introduction||Effect OF intensity||Voltage and frequency on photo-electric effect||Graphs OF photo current||Work-function:-metal