A long,straight wire is in the same plane as a rectangular,conducting loop.The wire carries a constant current I as shown in the figure.Which one of the following statements is true if the wire is suddenly moved toward the loop?
A)There will be no induced emf and no induced current.
B)There will be an induced emf,but no induced current.
C)There will be an induced current that is clockwise around the loop.
D)There will be an induced current that is counterclockwise around the loop.
E)There will be an induced electric field that is clockwise around the loop.

Question

A long,straight wire is in the same plane as a rectangular,conducting loop.The wire carries a constant current I as shown in the figure.Which one of the following statements is true if the wire is suddenly moved toward the loop? 
A)There will be no induced emf and no induced current. 
B)There will be an induced emf,but no induced current. 
C)There will be an induced current that is clockwise around the loop. 
D)There will be an induced current that is counterclockwise around the loop. 
E)There will be an induced electric field that is clockwise around the loop.

Quizplus · Accepted Answer

According to Faraday's law, when a magnetic field flux through a closed loop changes, an induced emf is created in the loop. This induced emf causes a current to flow in such a way as to oppose the change in flux. In this case, when the wire is moved towards the loop, the magnetic field passing through the loop increases. Therefore, an induced emf will be created in the loop, which will cause a current to flow in such a way as to oppose the increase in magnetic field. This can be achieved if the current flows in the opposite direction to the current in the long straight wire. Thus, the induced current will be counterclockwise around the loop, which is option D.

A Long,straight Wire Is in the Same Plane as a Rectangular,conducting