The de Broglie wavelength $( \lambda )$ associated with a photoelectron varies with the frequency $( v )$ of the incident radiation as, [$v _ { 0 }$ is threshold frequency]:
(1) $\lambda \propto \frac { 1 } { \left( v - v _ { 0 } \right) }$
(2) $\lambda \propto \frac { 1 } { \left( v - v _ { 0 } \right) ^ { \frac { 1 } { 4 } } }$
(3) $\lambda \propto \frac { 1 } { \left( v - v _ { 0 } \right) ^ { \frac { 3 } { 2 } } }$
(4) $\lambda \propto \frac { 1 } { \left( v - v _ { 0 } \right) ^ { \frac { 1 } { 2 } } }$