Question

Two metals A and B have work functions 4eV and 6eV respectively. Which metal has lower threshold wavelength for photoelectric effect?

Answer 1

We know that,
$E=hv=\frac{hc}{\lambda }$
Thus, $\lambda$ or threshold wavelength is inversely proportional to the energy or the work-function. so, metal B which has higher work-function of $6eV$ will have smaller threshold wavelength.