A clean sodium surface is illuminated in vacuum by monochromatic light of wavelength λ=250nm. The surface is connected to a collector plate through an adjustable potential difference.
Constants you may find useful:
$\begin{aligned}
c &= 3.00\times10^{8}\,\text{m}\,\text{s}^{-1}
h &= 6.63\times10^{-34}\,\text{J}\,\text{s}
e &= 1.60\times10^{-19}\,\text{C}
\end{aligned}$
(a) Calculate the frequency of the incident light.
(b) The work function of sodium is 2.28eV. Determine the maximum kinetic energy, in electron-volts, of the emitted photoelectrons.
(c) Find the magnitude of the potential difference that must be applied to just stop the photocurrent.