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प्रश्न
The strength of the electromagnet can be increased by
विकल्प
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
Why is soft iron used as the core of the electromagnet in an electric bell?
Name one device that uses an electromagnet.
Name the material used for preparing an electromagnet.
You are required to make an electromagnet from a soft iron bar by using a cell, an insulated coil of copper wire and a switch.
- Draw a circuit diagram to represent the process.
- Label the poles of the electromagnet.
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.
State two advantages of an electromagnet over a permanent magnet.
State two differences between an electromagnet and a permanent magnet.
How is the working of an electric bell affected, if alternating current be used instead of direct current?
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.
What is an electroscope? Describe the different stages of charging a gold leaf electroscope negatively with the help of a diagram.
