The work function \(W_{A}\) for photoelectric material \(A\) is \(2 \mathrm{eV}\)
and \(W_{B}\) for another photoelectric material \(B\) is \(4 \mathrm{eV}\). If
photons of energy \(E_{A}\) strike the surface of \(A\), the ejected
photoelectrons have a minimum de Broglie wavelength and photons of energy
\(E_{B}\) strike the surface \(B\), the ejected photoelectrons also have a minimum
de Broglie's wavelength. If \(E_{B}-E_{A}=\) \(0.5 \mathrm{eV}\) and \(V_{A}\) and
\(V_{B}\) are the respective stopping potentials, find \(V_{A}-V_{B}\).