Question

If the electric flux entering and leaving a closed surface are $6\times10^{6}$ and $9\times10^{6}$ $S.I$. units respectively, then the charge inside the surface of permittivity of free space $\varepsilon_{0}$ is

• A. $\varepsilon_{0} \times10^{6}$
• B. $- \varepsilon_{0} \times10^{6}$
• C. $- 2\varepsilon_{0} \times10^{6}$
• D. $3\varepsilon_{0} \times10^{6}$
• E. $2\varepsilon_{0} \times10^{6}$

Answer 1

Answer: (D)

Net flux = leaving flux-entering flux
$\phi=9 \times 10^{6}-6 \times 10^{6}=3 \times 10^{6}$
Here, $\phi=\frac{q}{\varepsilon_{0}} $
$q =\phi \varepsilon_{0}=3 \times 10^{6} \times \varepsilon$
$q =3 \,\varepsilon_{0} \times 10^{6}$