Q 12-04-072JEE MainJEE Main 2024 (5 Apr, Shift 1)Easy
In a co-axial straight cable, the central conductor and the outer conductor carry equal currents in opposite directions. The magnetic field is zero
Answer: (A) outside the cable
By Ampere's law, a circle outside the cable encloses a net current $I - I = 0$, so the field there is zero. Between the conductors and inside them the enclosed current is not zero (except on the axis).
Solution by Sreeraj P, M.Sc Physics