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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-shaped soft iron bar AB.
- What is the polarity induced at the ends A and B when the switch is pressed?
- Suggest one way to strengthen the magnetic field in the electromagnet.
- What will be the polarities at A and B if the direction of current is reversed in the circuit?
Tick the most appropriate answer.
Which of the following methods is used to magnetize a magnetic without touching it by a magnet?
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.
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
Electric bell ______.
Complete the following sentence :
On reserving the direction of current in a wire, the magnetic field produced by it gets _____.
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?
Point out three differences between an electromagnet and a bar (or permanent) magnet.
Write the answer in your words.
How is an electromagnet made?
