The potential at a point x due to some charges situated on the x- axis is given by $\;V (x) = \large\frac{20}{(x^2-4)} volt\;$. The electric field at x = 4m is given by

Question

$(a)\;(\large\frac{10}{9}) volt/m (\hat{i})\qquad(b)\;(\large\frac{10}{9}) volt/m(-\hat{i}) \qquad(c)\;(\large\frac{5}{3}) volt/m (\hat{i})\qquad(d)\;(-\large\frac{5}{3}) volt/m (\hat{i})$