In the given figure, the ratio of electric fluxes through surfaces \( S_1 \) and \( S_2 \) is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 1 : 3
By Gauss's law, the flux through a closed surface depends only on the charge enclosed by it; charges outside contribute nothing.
\( \displaystyle \phi = \frac{q_{\mathrm{enc}}}{\varepsilon_0} \)
Charges enclosed, read from the figure:
\( S_1: \ +2Q - Q = +Q \)
\( S_2: \ +2Q - Q + 3Q - Q = +3Q \quad (+4Q \text{ lies outside } S_2) \)
\( \displaystyle \frac{\phi_1}{\phi_2} = \frac{Q/\varepsilon_0}{3Q/\varepsilon_0} = \frac{1}{3} \)