Question

When a $10 \, μC$ charge is enclosed by a closed surface, the flux passing through the surface is $\phi.$ Now another $10 \, μC$ charge is placed inside the closed surface, then the flux passing through the surface is ______.

• A. $4\phi$
• B. $\phi$
• C. $2\phi$
• D. Zero

Answer 1

Answer: (C)

Electric flux $=\frac{q_{i n c}}{\epsilon _{0}}$
$\phi=\frac{10 μC}{\epsilon _{0}}$
If more $10μC$ charge is placed.
Electric flux $=\frac{20 μC}{\epsilon _{0}}=2\phi$