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प्रश्न
State two differences between an electromagnet and a permanent magnet.
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उत्तर
| Electromagnet | Permanent magnet |
| It is made up of soft iron | It is made up of steel. |
| The magnetic field strength can be changed. | The magnetic field strength cannot be changed. |
| The electromagnets of very strong field can be made. | The permanent magnets are not so strong. |
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?
Name and state the rule by which polarity at the ends of a current carrying solenoid is determined.
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 three uses of an electromagnet?
State the two properties of the magnetic lines of force around a circular coil.
How does a magnetic field set up by a solenoid change when number of turns are increased?
State two advantages of an electromagnet over a bar magnet.
State important properties (or characteristics) of magnetic lines of force around a straight conductor.
A current-carrying solenoid is suspended so as to freely rotate in a horizontal plane. State in what direction will it rest. Give a reason for your answer.
or
When a solenoid that is carrying current is freely suspended, it comes to rest in a particular direction. Why does this happen?
State and explain Maxwell’s Cork Screw Rule.
