Reflection of Electrons from Metal Surfaces

A beam of electrons from a hot-lime cathode was introduced into the space between two parallel plates so as to be incident against one of them at a large angle. Then the velocity distribution among the resulting secondary electrons was studied by observing the number of electrons which, overcoming different retarding potentials reached a Faraday cylinder. The experimental results obtained tend to show that the number of secondary electrons having velocities between zero and a given velocity $v$ may be expressed as the sum of two numbers one of which is proportional to the number of electrons having the velocity $v$ and the other of which is proportional to the energy of X-rays in the space between the two plates having the wave length which according to the quantum theory corresponds to the velocity $v$.