Question

If a electric flux leaving and entering from closed surface are $\varphi$ and $\varphi$ respectively, then the charge associated with closed surface will be ________.

• A. $\frac{{\varphi }_2-{\varphi }_1}{{\epsilon }_0}$
• B. $\frac{{\varphi }_1+{\varphi }_2}{{\epsilon }_0}$
• C. $\frac{{\varphi }_1-{\varphi }_2}{{\epsilon }_0}$
• D. ${\epsilon }_0({\varphi }_2-{\varphi }_1)$

Answer 1

Answer: (D)

${\epsilon }_0({\varphi }_2-{\varphi }_1)$

Net flux through surface $={\varphi }_2-{\varphi }_1$

using gauss's law

${\varphi }_2-{\varphi }_1=\frac{q_{enc}}{{\in }_0}$

$q_{enc}=\left({\varphi }_2-{\varphi }_1\right){\in }_0$

Hence,

option $\left(D\right)$ is correct answer.