In general, electric field strength E = (F)/q
E = \(\frac{q}{4\pi\varepsilon_0d^2}\)
⇒ 360 = \(\frac{9\times10^9\times50\times10^-6}{d^2}\)
solving, we have \(d^2\) = 1250
putting \(d^2\) = 1250 into the second equation,
E = \(\frac{9\times10^9\times120\times10^-6}{1250}\)
we have E = \(864NC^-1\)Â