Question

A charge $Q\mu C$ is placed at the centre of a cube. The flux coming out from any surface will be :

• A. $\frac{Q}{6{\epsilon }_0}\times {10}^{-6}$
• B. $\frac{Q}{6{\epsilon }_0}\times {10}^{-3}$
• C. $\frac{Q}{4{\epsilon }_0}$
• D. $\frac{Q}{8{\epsilon }_0}$

Answer 1

Answer: (A)

$\frac{Q}{6{\epsilon }_0}\times {10}^{-6}$

Total flux coming out $=\frac{Q_{enclosed}}{{ϵ}_0}$
$\int E.ds=\frac{Q\times {10}^{-6}}{{ϵ}_0}$ (guass law)
As Q is placed at center, flux coming out of all sides will be equal.
$\therefore$ flux from one of the side $=\frac{Q\times {10}^{-6}}{6{ϵ}_0}$
$=\frac{Q\times {10}^{-6}}{6{ϵ}_0}$