Physics - Modern Physics Question with Solution | TestHub

When stopping potential is applied no electron will reach the cathode and the current will becomes zero. $$\therefore e{V}_0=\frac{1}{2}m{v}_{\max }^2$$ Also, $\frac{1}{2}m{v}_{\max }^2=hv-$ work function $$\begin{array}{c}=4\mathrm{eV}-2\mathrm{eV}=2\mathrm{eV}\\ \Rightarrow e{V}_0=2\mathrm{eV}\Rightarrow \text{ stopping potential }=2\mathrm{V}\end{array}$$