Question

The inward and outward electric flux for a closed surface in units of $N-m^2/c$ are respectively $8\times {10}^3$ and $4\times {10}^3$. Then the total charge inside the surface is [where $ϵ$ = permittivity constant]

• A. 4 X 10³ C
• B. -4 X 10³ C
• C.
• D.

Answer 1

The correct option is D

By Gauss's law $\varphi =\frac{1}{{ϵ}_0}\left(Q_{enclosed}\right)$

$\Rightarrow Q_{enclosed}=\varphi {ϵ}_0=(-8\times {10}^3+4\times {10}^3){ϵ}_0$
$=-4\times {10}^3{ϵ}_0$ Coulomb.