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प्रश्न
How is the working of an electric bell affected, if alternating current be used instead of direct current?
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उत्तर
If an A.C. source is used in place of a battery, the core of the electromagnet will get magnetized, but the polarity at its ends will change. Since the attraction of the armature does not depend on the polarity of the electromagnet, the bell will still ring on pressing the switch.
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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.
Electromagnets are made up of :
The strength of the electromagnet can be increased by
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.
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.
State two differences between an electromagnet and a permanent magnet.
Why is soft iron used as the core of the electromagnet in an electric bell?
Name the material used for making the armature of an electric bell. Give a reason for your answer.
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.
Explain in detail the application of electromagnets.
Unlike magnetic poles ______ whereas like poles ______.
Assertion (A): When 2 long parallel wires, hanging freely are connected in parallel to a battery, they come closer to each other.
Reason (R): Wires carrying current in opposite directions repel each other.
Explain the working of the following device.
Magnetic levitation trains.
