A rectangular loop of wire is placed midway between two long straight parallel conductors as shown. The conductors carry currents i₁ and i₂ as indicated. If i₁ is increasing and i₂ is constant, then the induced current in the loop is: A) zero B) clockwise C) counterclockwise D) depends on i₁ - i₂ E) depends on i₁ + i₂

Question

Quizplus · Accepted Answer

The induced current in the rectangular loop is determined by Lenz's law which states that the direction of the induced current is such that it opposes the change in the magnetic flux causing it. 
In this case, the increasing current in the left conductor produces a magnetic field out of the page which interacts with the magnetic field produced by the constant current in the right conductor, resulting in a changing flux through the rectangular loop. To oppose this change, an induced current flows in the rectangular loop in a direction that produces a magnetic field into the page. This can be achieved by the current flowing counterclockwise around the loop, as shown in the diagram, so the correct answer is C.

A Rectangular Loop of Wire Is Placed Midway Between Two