KCET 2026 Physics Solved Paper

Concept:Gauss's law states that the net electric flux through a closed surface is $\frac{Q_{\text{enclosed}}}{\varepsilon_{0}}$.Only charges inside the surface contribute to the net flux.Explanation:For surface $S_{1}$, the enclosed charges are $-2 Q$ and $Q$.So, $Q_{\text{enclosed}} = -2 Q + Q = -Q$.Thus, net flux through $S_{1}$ is $\frac{-Q}{\varepsilon_{0}}$.Hence, (a) matches with (ii).For surface $S_{2}$, the enclosed charges are $Q$ and $-Q$.So, $Q_{\text{enclosed}} = Q + (-Q) = 0$.Thus, net flux through $S_{2}$ is zero.Hence, (b) matches with (iii).For surface $S_{3}$, all three charges $-2 Q$, $Q$, and $-Q$ are enclosed.So, $Q_{\text{enclosed}} = -2 Q + Q - Q = -2 Q$.Thus, net flux through $S_{3}$ is $\frac{-2 Q}{\varepsilon_{0}}$.Hence, (c) matches with (i).Answer:The correct matching is a - ii, b - iii, c - i.Therefore, option D is correct.