Question

A square loop of wire with a small resistance is moved with constant speed from a field free region into a region of uniform B field (B is constant in time) and then back into a field free region to the right. The self inductance of the loop is negligible

True/False:

a. When leaving the field the coil experiences a magnetic force to the left.

b. Upon entering the field, a clockwise current flows in the loop.

c. Upon leaving the field, a clockwise current flows in the loop.

d. When entering the field the coil experiences a magnetic force to the right.

Answer 1

The loop experiences a magnetic force to the left when leaving the field, a counterclockwise current flows when entering, a clockwise current flows when leaving, and a magnetic force to the left when entering the field.

Step-by-step explanation:

The statement a is true. When leaving the magnetic field, the loop experiences a magnetic force to the left. This is because the magnetic field lines are directed from right to left in the field and the loop opposes the change in magnetic flux by generating a current that creates its own magnetic field, according to Lenz's law.

The statement b is false. Upon entering the field, a counterclockwise current flows in the loop. This is because the increasing magnetic flux induces a current that opposes the increase, as stated by Lenz's law.

The statement c is true. Upon leaving the field, a clockwise current flows in the loop. This is because the decreasing magnetic flux induces a current that opposes the decrease, according to Lenz's law.

The statement d is false. When entering the field, the coil experiences a magnetic force to the left. This is because the magnetic field lines are directed from left to right in the field and the loop opposes the change in magnetic flux by generating a current that creates its own magnetic field, according to Lenz's law.