# Relation of the stopping potential $V_{\circ}$ of a metal and the maximum velocity $v$ of the photoelectrons
$\begin {array} {1 1} (a)\;V_{\circ} \sim \large\frac{1}{v^2} & \quad (b)\;V_{\circ} \sim v^2 \\ (c)\;V_{\circ} \sim v & \quad (d)\;V_{\circ} \sim \large\frac{1}{v} \end {array}$