Question

A wire is perpendicular to the plane of the paper. A ring of compass needles surrounds the wire in the plane of the paper with center of ring being the center of the wire. Initially there is no current in the wire. What happens after a steady dc current is established in the wire? ​

Answer 1

Answer:

The compass needles get aligned along the tangential direction of the ring of the needles.

Explanation:

Given ring of compass needles surrounds the wire perpendicularly.

• When there is no current, no defection in the magnetic needles.
• But when current is allowed through the wire, a magnetic field is set up around the wire, due to which the compass needle shows a deflection.
• The compass needles experiences a force and align themselves along the tangential direction of the ring of needles.