The figure below represents the variation of current with potential for a metal.

a. Identify the situation.
c. Even when the potential is zero, there is current. Explain.
d. Current is zero for a particular potential. How does this potential help in determining the velocity of electrons?

Explanation

a. Photoelectric effect
c. Incident photon possesses suitable energy in order to produce photoelectric current eventhough the potential is zero.
d. Using the relation `eV_(0)=(1)/(2)mv^(2)`
`v=sqrt((2eV_(0))/(m))V_(0)` - stopping potential