An electron beam and a photon beam pass through identical slits. On a distant screen, the first dark fringe occurs at the same angle for both of the beams. The electron speeds are much slower than that of light. Express the energy of a photon in terms of the kinetic energy K of one of the electrons. Express your answer in terms of the variable K, the speed of light in vacuum c, and the mass electron m_e. Which is greater, the energy of a photon or the kinetic energy of an electron? The photon has more energy than the electron. The electron has more energy than the photon.
