Question

Two charges of magnitudes - 2Q and +Q are located at points (a, 0) and (4a, 0) respectively. What is the electric flux due to these charges through a sphere of radius '3a' with its centre at the origin ?

Answer 1

As per Gauss's theorem, the electric flux through a closed surface enclosing a charge is equal to
$\frac{1}{{\epsilon }_0}$ times the magnitude of the charge enclosed. The sphere encloses a charge of $-2Q$ thus, $\varphi$ = $\frac{-2Q}{{\epsilon }_0}$