Question

Assertion : Ampere's law used for the closed loop shown in figure is written as $\oint \vec{B} \cdot d \vec{\ell}=\mu_0\left(i_1-i_2\right)$. Right side of it does not include $i_3$, because it produces no magnetic field at the loop.
Reason : The line integral of magnetic field produced by $i_3$ over the close loop is zero.

• A. If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
• B. If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
• C. If the Assertion is correct but Reason is incorrect.
• D. If the Assertion is incorrect and Reason is correct.

Answer 1

Answer: (D)

The magnetic field at any point on the closed loop is due to all the three currents, but line integral of $i_3$ over the closed loop will be zero.