Question

Choose the correct option for the given assertion and reason.
Assertion: Gauss's Theorem can only be applied for a closed surface.
Reason: Electric flux passing through an open surface can be obtained as well.

• A. Assertion is false, but reason is true
• B. Both assertion and reason are true and reason is the correct explantion of assertion.
• C. Assertion is true, but reason is false.
• D. Both assertion and reason are true and reason is not the correct explanation of assertion.

Answer 1

The correct option is D Both assertion and reason are true and reason is not the correct explanation of assertion.

We know that Gauss's Theorem is only applicable for a closed surface as in this theorem we consider the net charge enclosed by the closed surface.

$\varphi =\frac{q_{\text{enclosed}}}{{ϵ}_0}$

So, the assertion is correct.

Moreover, electric flux is the number of field lines passing perpendicular to a given surface. The surface may be open or closed.

So, reason is also correct.

But reason is not the correct explanation of assertion.

Hence, option $\left(b\right)$ is correct.