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Question
Use Lenz’s law to determine the direction of induced current in the situation described by the figure:
A wire of irregular shape turning into a circular shape.
Solution
According to Lenz’s law, the direction of the induced emf is such that it tends to produce a current that opposes the change in the magnetic flux that produced it.
A greater area and, by extension, a stronger magnetic flux, are the results of a change in shape. In order to create opposing flux, Lenz's law is used to build up an induced current in the circular wire in an anticlockwise direction. Thus, the upward-directed magnetic field is a result of it.
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