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प्रश्न
State Lenz's law. Illustrate, by giving an example, how this law helps in predicting the direction of the current in a loop in the presence of a changing magnetic flux.
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उत्तर
(i)According to Lenz's law, the polarity of emf induced in the coil always opposes the change in the magnetic flux responsible for production of induced emf.
(ii) Lenz's law is used to determine the direction of current induced in the closed circuit. Let us consider an example to illustrate it. When a north pole of a bar magnet is brought closer to a coil, as shown in figure, the amount of magnetic flux linked with the coil increases. So, the current induced in the coil is directed such that it opposes this change in magnetic flux responsible for production of induced current, which is possible only when the current induced in the coil is in anticlockwise direction of the observer on the side of the magnet.
Similarly, the direction of induced current can be found when north pole of bar magnet is moved away from the coil. As the magnetic flux in this case decreases, the induced current is in the clockwise direction.
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संबंधित प्रश्न
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.
Predict the directions of induced currents in metal rings 1 and 2 lying in the same plane where current I in the wire is increasing steadily.
Predict the direction of induced current in metal rings 1 and 2 when current I in the wire is steadily decreasing?
A bar magnet is moved along the axis of a copper ring placed far away from the magnet. Looking from the side of the magnet, an anticlockwise current is found to be induced in the ring. Which of the following may be true?
(a) The south pole faces the ring and the magnet moves towards it.
(b) The north pole faces the ring and the magnet moves towards it.
(c) The south pole faces the ring and the magnet moves away from it.
(d) The north pole faces the ring and the magnet moves away from it.
Explain, with the help of a suitable example, how we can show that Lenz's law is a consequence of the principle of conservation of energy.
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Predict the direction of induced current in the situation described by the following figure.
