A charge $Q \mathrm{C}$ is placed at the center of a cube. If $\varepsilon_0$ is the permittivity of vacuum…

A charge $Q \mathrm{C}$ is placed at the center of a cube. If $\varepsilon_0$ is the permittivity of vacuum then the flux through one face and two opposite faces of the cube is respectively
  1. $\frac{Q}{6 \epsilon_0}, \frac{Q}{3 \epsilon_0}$
  2. $\frac{Q}{3 \epsilon_0}, \frac{Q}{2 \epsilon_0}$
  3. $\frac{Q}{12 \epsilon_0}, \frac{Q}{6 \epsilon_0}$
  4. $\frac{Q}{\epsilon_0}, \frac{Q}{2 \epsilon_0}$

Solution

A charge $Q \mathrm{C}$ is placed at the center of a cube. Total flux radiated $=\frac{Q}{\varepsilon_0}$ $\therefore$ from one face would be $\frac{Q}{6 \varepsilon_0}$ due to the six-fold symmetry of the cube. And from two opposite faces, it would be $\frac{Q}{3 \varepsilon_0}$ due to three-fold symmetry. ~

Asked in: MHT CET 2022 (06 Aug Shift 1)

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