A long straight wire is in the plane of a rectangular conducting loop. The straight wire carries a constant current i, as shown. While the wire is being moved toward the loop, the current in the loop is:
A) zero
B) clockwise
C) counterclockwise
D) clockwise in the left side and counterclockwise in the right side
E) counterclockwise in the left side and clockwise in the right side

Question

A long straight wire is in the plane of a rectangular conducting loop. The straight wire carries a constant current i, as shown. While the wire is being moved toward the loop, the current in the loop is: 
A) zero 
B) clockwise 
C) counterclockwise 
D) clockwise in the left side and counterclockwise in the right side 
E) counterclockwise in the left side and clockwise in the right side

Quizplus · Accepted Answer

As the wire is being moved towards the loop, the changing magnetic field around the wire induces an EMF in the loop. To oppose the change in flux, an induced current is created in the loop which creates its own magnetic field that opposes the external magnetic field. Using the right-hand rule, we can see that the induced current must flow counterclockwise to create a magnetic field that opposes the magnetic field of the wire.

A Long Straight Wire Is in the Plane of a Rectangular