Predict the direction of induced current in the situations described by the following Figs. 6.18(a) to (f ).
Predict the direction of induced current in the situations described by the following Figs. 6.18(a) to (f ).
Solution and Explanation
The direction of the induced current in a closed loop is given by Lenz’s law. The given pairs of figures show the direction of the induced current when the North pole of a bar magnet is moved towards and away from a closed loop respectively. 
Using Lenz’s rule, the direction of the induced current in the given situations can be predicted as follows:
(a) The direction of the induced current is along qrpq.
(b) The direction of the induced current is along prqp.
(c) The direction of the induced current is along yzxy.
(d) The direction of the induced current is along zyxz.
(e) The direction of the induced current is along xryx.
(f) No current is induced since the field lines are lying in the plane of the closed loop.
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Concepts Used:
Lenz’s law
Lenz’s law states that the induced electromotive force with different polarities induces a current whose magnetic field opposes the change in magnetic flux through the loop in order to ensure that original flux is maintained through the loop when current flows in it.
It depends on the principle of conservation of energy and Newton’s third law. To determine the direction of the induced current is most convenient method . Induced current states that he direction of an induced current is always such as to oppose the change in the circuit or the magnetic field that produces it.
Lenz’s Law Formula
The Lenz’s Law is reflected in the formula of Faraday’s law. Here the negative sign is contributed from Lenz’s law. The expression is –
Where,
