Question

Assertion :If we see along the axis of a charged ring, the magnitude of electric field is minimum at centre and magnitude of electric potential is maximum. Reason: Electric field is a vector quantity while electric potential is scalar.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

The electric field for a charged ring is given as,

$E=kQz/(z^2+R^2{)}^{3/2}$ where $k=1/4\pi {ϵ}_o$, $R$ is the ring radius, $z$ is the distance from center of ring along the axis of ring, and $Q$ is the total charge on the ring. So at center, $z=0$$\Rightarrow E=0$ So $E$ is minimum at center.

And, Electric potential is $V=kQ/(z^2+R^2{)}^{1/2}$

So at center, potential is maximum.

Thus assertion is true.

Reason is also true, as electric field is vector while, electric potential is a scalar.

But reason is not correct explanation of the assertion.