## NĐGK 3 years ago Calculate the wavelength of a proton with energy 2.45 eV. what's different between proton and photon formula? can anyone tell me? thank you

one formula (planck's) is for massless particles (i.e. photons) the other (deBroglie's) is for things with mass... so, for this question, find the velocity, v, of the particle: $K.E.=\frac{ 1 }{2 }mv ^{2}$ then use the deBroglie equation: $\lambda=\frac{ h }{ mv }$ wavelength is in meters, velocity in m/s, mass in Kg.