What is the Photoelectric Effect?

 In very fundamental terms, it is when electrons are released from a particular type of metal upon receiving adequate energy from incident light. 

So basically, light comes down and strikes the metal. If the energy of the light wave is sufficient, the electron will then shoot out of the metal with some velocity and kinetic energy.

The Photoelectric Effect

"When light strikes a material, electrons are 

emitted. The radiant energy supplies the work

necessary to free the electrons from the 

surface."