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प्रश्न
The strength of the electromagnet can be increased by
पर्याय
reversing the directions of current
using alternating current of high frequency
increasing the current in the coil
decreasing the number of turns of coil
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उत्तर
The strength of the electromagnet can be increased by increasing the current in the coil
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संबंधित प्रश्न
Name one device that uses an electromagnet.
Name the material used for preparing an electromagnet.
The following figure shows a coil wound around a soft iron bar XY.
- State the polarity at the ends X and Y as the switch is pressed.
- Suggest one way of increasing the strength of electromagnet so formed.
A coil of insulated copper wire is wound around a piece of soft iron and current is passed in the coil from a battery. What name is given to the device so obtained? Give one use of the device mentioned by you.
Show with the aid of a diagram how a wire is wound on a U-shaped piece of soft iron in order to make it an electromagnet. Complete the circuit diagram and label the poles of the electromagnet.
State two advantages of an electromagnet over a permanent magnet.
Explain, why steel is used in preference to soft iron for making permanent magnets while soft iron is used in preference to steel for making electromagnets.
Explain in detail the application of electromagnets.
Unlike magnetic poles ______ whereas like poles ______.
Explain the working of the following device.
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