Energy required to stop the ejection of electrons from $Cu$ plate is 0.24eV.Calculate the work function when radiations of $\lambda=253.7nm$ strikes the plate.

Question

$\begin{array}{1 1}(a)\;3.65eV&(b)\;2.65eV\\(c)\;4.65eV&(d)\;1.65eV\end{array}$