(Solved): (a) What is the maximum number of electrons that can be emitted from a potassium surface having a w ...

(a) What is the maximum number of electrons that can be emitted from a potassium surface having a work function of $2.40\mathrm{eV}$ if it absorbs $3.25\times 10^{-3}\mathrm{J}$ of radiation at a wavelength of $300\mathrm{nm}$ ? (b) A symmetric spectral peak is centered at a wavelength of $400\mathrm{nm}$ and has a linewidth of $10\mathrm{nm}$. Calculate the minimum lifetime of the excited state associated with this spectral transition line using the Heisenberg uncertainty principle.