Question

A loop of flexible wire of irregular shape carrying current is placed in an external magnetic field. Identify the effect of the field on the wire.

• A. Loop assumes circular shape with its plane parallel to the field
• B. shape of the loop remains unchanged
• C. wire gets stretched to become straight.
• D. loop assumes circualr shape with its plane normal to the field

Answer 1

The correct option is D loop assumes circualr shape with its plane normal to the field

The loop will orient such that the maximum magnetic flux passes through it. For this to happen loop should have maximum area and it should orient such that plane of the loop is perpendicular to the magnetic field (so that maximum magnetic field lines passes through it). For a fixed perimeter circle has maximum area. So it will acquire the shape of the circle.