Q. A long, straight, solid metal wire of radius 2 mm carries a current uniformly distributed over its circular cross-section. The magnetic field induction at a distance 2 mm from its axis is $B$. Then the magnetic field induction at distance 1 mm from axis will be
A) $B$
B) $B$/2
C) 2 $B$
D) $B$
Explanation
(b) At a point inside the metal wire carrying current. Magnetic field induction $B \propto r.$
$\therefore\ B^{'} = \frac{B}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.