A point charge $+q$ is placed symmetrically at the centre of a cube. The total electric flux emergin

Question

A point charge $+q$ is placed symmetrically at the centre of a cube. The total electric flux emerging from any two opposite faces of the cube is

Professor PC Thomas Classes · Answer

(a) : By Gauss's Law, the total electric flux emerging from the entire cube enclosing a charge $q$ is $\Phi = \frac{q}{\varepsilon_0}$. Since the charge is at the geometric centre, the flux is distributed equally among all 6 faces. The flux through a single face is $\frac{q}{6\varepsilon_0}$. Therefore, the flux through any two opposite faces combined is $2 	imes \frac{q}{6\varepsilon_0} = \frac{q}{3\varepsilon_0}$.