A bar magnet is held above the center of a wire loop lying in the horizontal pla

Question

A bar magnet is held above the center of a wire loop lying in the horizontal plane as shown in the figure below. The south end of the magnet is toward the loop. After the magnet is dropped, what is true of the current in the resistor as viewed from above? (Select all that apply.)

A It is counterclockwise as the magnet falls toward the loop.

B It is always clockwise.
C It is clockwise as the magnet falls toward the loop.
D It is clockwise after the magnet has moved through the loop and moves away from it.
E It is first counterclockwise as the magnet approaches the loop and then clockwise after it has passed through the loop.


Im pretty sure D is one of them but im not sure what else would be an appropriate answer
heres the image:

http://www.webassign.net/serpse9/31-oq-007.gif

Explanation / Answer

Lenz’s law:

The direction of induced current in a loop is such a way that the magnetic flux due to this current should be opposing the original magnetic field.

The magnetic field due to a bar magnetic is always points from North Pole to South Pole. As the south end of the bar magnet falling towards the loop, magnetic field lines passes though the loop in vertical upward direction. According to the Len’s law, the magnetic field lines due to induced current should be in opposite (downward) direction to the original field (upward).

Use the Ampere’s right hand rule; the current flow in the loop is clockwise.

After the magnet has moved through the loop, the direction of original magnetic field through the loop will be in opposite to initial direction. Thus, the induced current in the loop is now in counterclockwise direction.

Thus, only the option C is correct and all other options are not correct.

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