Consider three point charges \(-2Q, Q\) and \(-Q\) and three surfaces \(S_1, S_2\) and \(S_3\) as shown in the figure. Match the entries of List-I with that of List-II.

List-I	List-II
(a) Net flux through \(S_1\)	(i) \(\dfrac{-2Q}{\varepsilon_0}\)
(b) Net flux through \(S_2\)	(ii) \(\dfrac{-Q}{\varepsilon_0}\)
(c) Net flux through \(S_3\)	(iii) Zero

According to Gauss's Law, the net electric flux through any closed surface is given by \(\Phi = \dfrac{Q_{\text{enclosed}}}{\varepsilon_0}\).

For surface \(S_1\), the enclosed charges are \(-2Q\) and \(Q\).
Net charge enclosed by \(S_1 = -2Q + Q = -Q\).
Net flux through \(S_1 = \dfrac{-Q}{\varepsilon_0}\).
Thus, (a) matches with (ii).

For surface \(S_2\), the enclosed charges are \(Q\) and \(-Q\).
Net charge enclosed by \(S_2 = Q + (-Q) = 0\).
Net flux through \(S_2 = 0\).
Thus, (b) matches with (iii).

For surface \(S_3\), the enclosed charges are \(-2Q\), \(Q\), and \(-Q\).
Net charge enclosed by \(S_3 = -2Q + Q + (-Q) = -2Q\).
Net flux through \(S_3 = \dfrac{-2Q}{\varepsilon_0}\).
Thus, (c) matches with (i).

The correct matching is a - ii, b - iii, c - i.

Answer: a - ii, b - iii, c – i