Evan's Space

Wonders of Physics

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Electromagnetic Induction

Consider these two scenarios.

Scenario 1 A wire moves vertically between the magnets. An induced current is produced when the wire cuts the magnetic lines of force. The direction of the induced current is out of paper and magnets are stationary. Is the wire moving up, A, or downwards, B?


Solutions: Since force is applied to the wire and an induced current is produced, Fleming’s Right Hand Rule (FRHR) is applied here. Using FRHR, you will be able to determine that the direction of the motion of wire (force) is downwards (towards B).

Scenario 2 If now the wire is stationary, but the magnets move vertically instead.  An induced current that flows out of paper is produced as the magnets move. Which direction does the magnets move, upwards (towards A) or downwards (towards B)?


Solutions: From Scenario 1, FRHR is applied to know that wire moves down in order to produce an induced current out of paper. Here, wire is stationary, and magnets move instead. One has to know that the effect of wire moving down (scenario 1) is the same as the magnets moving up (scenario 2). In both cases, the way the wire cuts the magnetic lines of force is the same. Hence, in this scenario, the magnets are moving up (towards A) in order to achieve induced current out of paper.