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प्रश्न
Describe briefly three main useful application of eddy currents ?
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उत्तर
Application of Eddy currents:
(i) Induction furnace: When a piece of metal, which is to be converted into an alloy, is wound by the circular conducting coil, a high frequency alternating current is passed through the coil which in turns changes the magnetic flux associated with the metal. This produces strong eddy currents that generate a large amount of heat in the metal block and melts it easily.
(ii) Electric brakes: Electromagnets are placed in the trains just above the rails. Whenever these electromagnets are activated, eddy currents are produced in such a way that they oppose the motion and stop the train.
(iii) Induction motor: A rotating magnetic field produces strong eddy currents in the rotor of the motor, which starts rotating in the direction of the field.
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संबंधित प्रश्न
How are eddy currents produced ?
If the magnetic field outside a copper box is suddenly changed, what happens to the magnetic field inside the box? Such low-resistivity metals are used to form enclosures which shield objects inside them against varying magnetic fields.
How are eddy currents generated in a conductor which is subjected to a magnetic field?
Write two examples of their useful applications .
Why and where are eddy currents are undesirable? How are they minimized?
The plane in which eddy currents are produced in a conductor is inclined to the plane of the magnetic field at an angle equal to ______.
Two simple pendula of length L and 4L are pulled aside to the right and are at rest so that they make an angle 30° with the vertical. They are then released simultaneously at time t = 0. The time after which they will be in phase is ______.
Consider a metallic pipe with an inner radius of 1 cm. If a cylindrical bar magnet of radius 0.8 cm is dropped through the pipe, it takes more time to come down than it takes for a similar unmagnetised cylindrical iron bar dropped through the metallic pipe. Explain.
