Question

A metal has a work function of 2eV and is illuminated by monochromatic light of wavelength 500nm. Calculate the threshold wavelength, maximum energy of photoelectrons and the stopping potential.

Answer 1

$$\begin{gathered} Dearstudent \\ for{\lambda }_{th} \\ \varphi =\frac{hc}{{\lambda }_{th}} \\ 2=\frac{4.13\times {10}^{-15}\times 3\times {10}^8}{{\lambda }_{th}} \\ {\lambda }_{th}=6.19\times {10}^{-7}m \\ maxenergyofphotoelectrons \\ \frac{hc}{{\lambda }_{light}}=\phi +E \\ \frac{4.13\times {10}^{-15}\times 3\times {10}^8}{500\times {10}^{-9}}=2+E \\ E=0.478eV \\ stoppingpotential \\ V=EinJoules/charge \\ V=\frac{0.478\times 1.6\times {10}^{-19}}{1.6\times {10}^{-19}} \\ =0.478volts \end{gathered}$$