A circular conducting loop lies in the $x y$ plane of a certain reference frame. We are looking down on the loop with the $+z$ axis pointing up at us.
-(a) If the loop is immersed in a magnetic field that points in the $-z$ direction and is increasing in magnitude as time passes, which way will current flow in the loop?
A) Counterclockwise
B) Clockwise
C) No current will flow.

Question

Quizplus · Accepted Answer

According to Lenz's Law, the induced current in the loop will flow in such a direction as to oppose the change in magnetic flux through the loop. Since the magnetic field is increasing in the $-z$ direction, the induced current will flow counterclockwise when viewed from the $+z$ direction, to create a magnetic field in the $+z$ direction to oppose the increase in the external magnetic field.

A Circular Conducting Loop Lies in The xyx yxy Plane of a Certain Reference Frame

A Circular Conducting Loop Lies in The $x y$ Plane of a Certain Reference Frame