(a)[3]
Electromagnetic radiation with one fixed frequency is incident on a metal surface, causing an electron to be emitted. Explain why the maximum kinetic energy of the electron does not depend on the intensity of the incident radiation.
(b(i))[3]
Ultraviolet radiation with wavelength $250\,\text{nm}$ falls on the surface of a sheet of zinc. The maximum kinetic energy of the emitted electrons is $1.4\,\text{eV}$. Determine, in $\text{eV}$, the energy of a photon in the ultraviolet radiation.
(b(ii))[2]
Determine, in $\text{eV}$, the work function energy for the zinc surface.