Question

When ${K.E.}_{max}$ of photoelectrons is zero then frequency of incident photon relative to threshold frequency is

• A. Less
• B. Equal
• C. Greater
• D. Smaller

Answer 1

The correct option is B Equal

Maximum kinetic energy of the photoelectrons $K.E_{max}=h{\nu }_{incident}-h{\nu }_{th}$
For $K.E_{max}=0$, we get ${\nu }_{incident}={\nu }_{th}$
Thus frequency of incident photon is equal to the threshold frequency when $K.E_{max}$ of photoelectrons is zero.