Question

If the maximum kinetic energy of the electrons emitted by a photocell is 4 eV, what is the stopping poential?

Answer 1

Relation between kinetic energy in terms of stopping potential is given by:

K.E. = eV₀
where e= charge on the electron.
V₀= stopping potential
given kinetic energy of an electron is 4 eV.
To convert it into joule we multiply it by e. (As 1 eV = 1.6 X 10^-19J)

therefore 4e = eV_​0
V₀= 4 volts
Hence stopping potential is 4 volts.