I know, I know...I'm asking for help on my homework. I just don't understand how to find what the energy of a photon whose wavelength is equal to the Compton wavelength of an electron (.00241 nm). I'm using (hc)/lamda = E (1240 eV nm)/(0.00241 nm) = 514.522 MeV But the damn homework is saying my answer is wrong! Any help would be appreciated.