Using the photoelectric effect as context, explain what is meant by work function energy.
By reference to the photoelectric effect, explain why monochromatic incident light still produces emitted electrons with a range of kinetic energies, up to a maximum.
Electromagnetic radiation with frequency $f$ strikes a metal surface. Figure 7.1 shows how the maximum kinetic energy $E_{\text{MAX}}$ of electrons emitted from the surface varies with frequency $f$.
Use Fig. 7.1 to find the work function energy of the metal surface.
A second metal has a greater work function energy than the metal in (i). On Fig. 7.1, draw a line to represent how $E_{\text{MAX}}$ varies with $f$ for this metal.
Explain why the graphs in (i) and (ii) are independent of the intensity of the incident radiation.