A current of $1.0\;mA$ s flowing through a potentio meter wire of length $4\;m$ and of resistance $4 \Omega$ ,find the potential gradient of the potentio meter wire .

Question

$\begin{array}{1 1} 10^{-3}\;V/m \\ 5^{-3}\;V/m \\ 20^{-3}\;V/m \\ 0 \end{array}$