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प्रश्न
Name the material of core in (a) an electric bell, (b) electromagnet, (c) a d.c. motor, (d) an a.c. generator and (e) a transformer.
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उत्तर
Soft iron is used in all.
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संबंधित प्रश्न
The diagram shows a coil wound around a U shape soft iron bar AB.
1) What is the polarity induced at the ends A and B when the switch is pressed?
2) Suggest one way to strengthen the magnetic field in the electromagnet
3) What will be the polarities at A & B if the direction of current is reversed in the circuit?
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.
What is an electromagnet?
State two factors on which the magnitude of an induced e.m.f. in the secondary coils of a transformer depends.
State two factors on which the strength of induced e. m.f. depends.
A straight wire is held vertical and current is passed in it in the upward direction. A compass needle is kept near the wire in north of it. How is the needle deflected? What is the change in the deflection of the needle if the current in wire is reversed?
State the purpose of the iron core.
How does a magnetic field set up by a solenoid change when a soft iron core is inserted inside solenoid?
How does a magnetic field set up by a solenoid change when cross-sectional area of solenoid is increased?
Write the answer in your word.
How is an electromagnet made?
