PHOTOELECTRIC EFFECT - Q3

3) What is photoelectric effect?
Ans: 

• The emission of free electrons from a metal surface when light of sufficient frequency incident on the metal surface is called photoelectric effect. 
• The maximum kinetic energy K(max) of an ejected electron is given by K(max) = ℎf − ϕ where ℎ is the Planck’s constant, f is the frequency of the incident photon and ϕ is the work function of the metal.