Question

When the rotational path of the magnetic field intensity is zero, then the current in the path will be

(a) 1

(b) 0

(c) ∞

(d) 0.5

I got this question in an internship interview.

The above asked question is from Ampere Law topic in section Magnetostics of Electromagnetic Theory

Answer 1

The correct option is (b) 0

For explanation: By Ampere law, Curl(H) = J. The rotational path of H is zero, implies the curl of H is zero. This shows the current density J is also zero. The current is the product of the current density and area, which is also zero.