A photon of wavelength 450 nm strikes a metal surface whose work function is 2.5 eV. Calculate
the velocity of the photelectron.

Explanation

`KE=(1)/(2) mv^(2) rArr v^(2) =(2xxKE)/(m) rArr v =sqrt((2KE)/(m)) = sqrt((2xx4.0xx10^(-18)J)/(9.1xx10^(-31)))=2.96xx10^(6) ms^(-1)`