Question

wavelength of a 1keV photon is 1.24*10^9 m. what is the frequency of 1MeV photon?

Answer 1

Energy E = hν = hc/λ = 1 keV  -----------(1)Wavelength λ = 1.24 x 10-9 m  -----------(2)From (1) and (2), we get hc = λ x 1 keV = 1.24 x 10-9 m x 1 keV = 1.24 x 10-9 m. 103eV = 1.24 x 10-6 eV.m If E = hc/λ = 1 MeV   1/λ = E/hc = 1 x 106 eV/(1.24 x 10-6 eV.m)                  = 0.81 x 1012/m Frequency ν = c/λ = (3 x 108 m/s) x 0.81 x 1012/m                                = 2.43x 1020/s                                 = 2.43 x 1020 Hz