1. The problem statement, all variables and given/known data Calculte the frequency of the proton with a kinetic energy of 1.97*10-16ev if the work function of the metal is 1.33*10-16 (IeV=1.6*10-19J, h=6.60*10-34Js 2. Relevant equations E = hf-hfo=hf-Wo Where E= maximum kinetic energy h= Plancks's constant Wo=hfo=work function f=frequency of the incidented light 3. The attempt at a solution from E = hf-Wo, we have f = E+Wo/h f = 1.97*10-16+1.33*10-16/6.60*10-34 What about the IeV=1.6*10-19J? Where can I subtitute that one into?