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A permanent magnet is held in a vertical position on top of a loop of wire that is in the horizontal plane, as shown in the figure. The south pole of the magnet points towards the loop. After leaving
If the magnet falls, which of the following statements is true regarding the induced current in the loop, if viewed from above?
i). The current rotates in a clockwise direction as the magnet approaches the loop.
ii). The current rotates counterclockwise as the magnet approaches the loop.
iii). The current rotates in a clockwise direction when the magnet has already passed through the loop and is moving away from it.
iv). the current always goes in a clockwise direction.
v). The current goes counterclockwise as the magnet approaches the loop, and then goes clockwise as it passes the loop.
Clearly explain your answers.
The south pole of the given magnet is facing the loop, the magnet is moving downward, due to which the flux link with the coil will change and emf, thus a current will be produced in the circular loop. The direction of the induced current in the circular loop is given by using Lenz's law according to which, the direction of the induced current will be such that it opposes the field due to which it is produced.
From the above discussion, the direction of the current will be such that it will oppose the downward motion of the magnet. This means that the coil facing the south pole of the magnet should act like the south pole so that it will repel the magnet and thus the downward motion can be opposed.
When the magnet passes through the loop, there is no linkage of flux, when it crosses the coil, the north pole of the magnet moves away from the coil thus the direction of the induced current will be such that the coil will attract the magnet closer and thus acts as the south pole. Thus, the direction of the current will be counterclockwise.
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