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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
Show that Lenz's law is a consequence of conservation of energy.
Consider the situation shown in figure. If the closed loop is completely enclosed in the circuit containing the switch, the closed loop will show _______________ .
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.
Which of the following statements is not correct?
A wire in the form of a tightly wound solenoid is connected to a DC source, and carries a current. If the coil is stretched so that there are gaps between successive elements of the spiral coil, will the current increase or decrease? Explain.
A metallic ring of mass m and radius `l` (ring being horizontal) is falling under gravity in a region having a magnetic field. If z is the vertical direction, the z-component of magnetic field is Bz = Bo (1 + λz). If R is the resistance of the ring and if the ring falls with a velocity v, find the energy lost in the resistance. If the ring has reached a constant velocity, use the conservation of energy to determine v in terms of m, B, λ and acceleration due to gravity g.
In the above diagram, a strong bar magnet is moving towards solenoid-2 from solenoid-1. The direction of induced current in solenoid-1 and that in solenoid-2, respectively, are through the directions:
In the diagram given below, a strong bar magnet is moving towards solenoid-2 from solenoid-1. The direction of induced current in solenoid-1 and that in solenoid-2, respectively, are through the directions:
