When a metal was exposed to photons at a certain frequency, electrons were emitted with a maximum kinetic energy. What is the relationship between the frequency of the photons and the maximum kinetic energy of the emitted electrons?
1) The maximum kinetic energy of the emitted electrons is directly proportional to the frequency of the photons.
2) The maximum kinetic energy of the emitted electrons is inversely proportional to the frequency of the photons.
3) The maximum kinetic energy of the emitted electrons is independent of the frequency of the photons.
4) The maximum kinetic energy of the emitted electrons is equal to the frequency of the photons.