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प्रश्न
Why and where are eddy currents are undesirable? How are they minimized?
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उत्तर
Undesirable effects of eddy currents:
The soft iron core is used in dynamo transformers, motors, generators, etc. When a.c is passed through these instruments the flux changes and eddy currents are set up in the core. Therefore, the core is heated up so the electrical energy is wasted in the form of heat energy.
Minimization of the undesirable effect of eddy current:
- To minimize the undesirable effect of eddy currents, laminated or insulated iron core is used which minimizes the magnitude of eddy currents.
- If the surface area of the metal plate is reduced, amount of eddy current generated is reduced.
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संबंधित प्रश्न
State any two causes of energy loss in actual transformers.
How are eddy currents produced ?
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Metallic (nonferromagnetic) and nonmetallic particles in a solid waste may be separated as follows. The waste is allowed to slide down an incline over permanent magnets. The metallic particles slow down as compared to the nonmetallic ones and hence are separated. Discuss the role of eddy currents in the process.
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State applications of eddy currents.
In which of the following devices, the eddy current is not used ______
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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 ______.
A constant retarding force of50 N is applied to a body of mass 20 kg moving initially with a speed of 15 ms-1. How long does the body take to stop?
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Eddy currents are also known as ______
A metal plate is getting heated. It can be because ______.
- a direct current is passing through the plate.
- it is placed in a time varying magnetic field.
- it is placed in a space varying magnetic field, but does not vary with time.
- a current (either direct or alternating) is passing through the plate.
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.
