c
(c)The net field will be zero at a point outside the charges and near the charge which is smaller in magnitude.
Suppose \(E.F.\) is zero at \(P\) as shown.
Hence at \(P\); \(k.\frac{{8q}}{{{{(L + l)}^2}}} = \frac{{k.(2q)}}{{{l^2}}}\) \(==>\) \(l = L.\)
So distance of \(P\) from origin is \(L + L = 2L.\)
