The de Broglie wavelength of an electron and the wavelength of a photon are the same. The ratio between the energy of that photon and the momentum of that electron is (c is velocity of light, h is Planck's constant)

According to question, we have De Broglie wavelength of electron = Wavelength of photonhpelectron =hcEphoton , where p is the momentum of electron, c is speed of light, E is energy of photon and h is Planck's constant.Ephoton pelectron =hch=c