An atomic transition takes place from to the ground state . What is the wavelength of the photon this transition will emit?

It is possible that electrons can be ejected from a metal plate by light. Which of the following properties of light accounts for this phenomena?

A physicist is trying to determine the identity of a metal by experimentally finding its work function and then comparing the experimental value to a list of known values. If the physicist shines light with a frequency of on the metal and records an electron speed of , what is the work function of the metal?