Consider a beam of electrons (each electron with energy E0) incident on a metal surface kept in an evacuated chamber. Then
(a) no electrons will be emitted as only photons can emit electrons.
(b) electrons can be emitted but all with an energy, E0.
(c) electrons can be emitted with any energy, with a maximum of E0 – φ (φ is the work function).
(d) electrons can be emitted with any energy, with a maximum of E0.
