An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is
C(2mE)12
1c2mE12
1cE2m12
E2m12
(c being velocity of light)
For electron of energy E
de-Broglie wavelength, λe=hp=h2mE
For photon of energy,E=hv=hcλp
⇒λp=hcE
∴λeλp=h2mE×Ehc=1cE2m1/2