An electron (of mass m) and a photon have the same energy E in the range of few eV. The ratio of the de Broglie wavelength associated with the electron and the wavelength of the photon is. (c = speed of light in vacuum)
1
(E/2m)1/2
2
1/c (2E/m)1/2
3
c(2mE)1/2
4
1/c (E/2m)1/2