In the photoelectric effect, state what is meant by work function energy.
A clean metal surface has a work function energy of $5.5 \times 10^{-19}\,\text{J}$. Radiation with wavelength $280\,\text{nm}$ falls on the metal surface, which is in a vacuum.
Calculate the energy of the photon.
Calculate the maximum speed $v_{\text{MAX}}$ of the electrons that leave the surface.
Explain why the majority of the emitted electrons will have a speed lower than $v_{\text{MAX}}$.
The electromagnetic radiation incident on the metal surface may vary in intensity or in frequency. Fill in Fig. 11.1 using either ‘increases’ or ‘decreases’ or ‘no change’ to show how the maximum speed and the rate of emission of electrons are affected by these changes: reduced intensity at constant frequency; increased frequency at constant intensity.