Question

Two metals A and B have work function 4 electron volts and 10 electron volts respectively, Which metal has higher threshold wavelength?

Answer 1

consider a particle of mass 'm' rotating about a
We know,
$E=hc=\frac{hc}{\lambda }$
Thus, $\lambda$ or threshold wavelength is inversely proportional to the energy or the work-function.
So the metal A will have a higher threshold wavelength as its work-function is less compared to that of metal B.