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प्रश्न
Point out three differences between an electromagnet and a bar (or permanent) magnet.
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उत्तर
| Electromagnet | Bar Magnet |
| 1. An electromagnet exhibits a much stronger magnetic field. | A bar magnet is not able to exhibit a strong magnetic field. |
| 2. Its polarity can be reversed by reversing the direction of current flowing in the turns of the coil (or solenoid). | Its polarity is fixed. |
| 3. It is a temporary magnet, it behaves as a magnet only when the current flows through the solenoid. | It is a permanent magnet and cannot be readily demagnetized. |
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?
Name two factors on which the strength of magnetic field of an electromagnet depends and state how does it depend on the factors stated by you.
State two differences between an electromagnet and a permanent magnet.
How does a magnetic field set up by a solenoid change when number of turns are increased?
Why is soft iron generally used as the core of the electromagnet?
State the condition when an electric charge can give rise to a magnetic field.
What is a permanent magnet? Give one use of it.
State the energy change that takes’place in a D. C. motor.
State the position of armature coil relative to the direction of magnetic field, in a D. C. motor when the deflecting couple acting an the coil is maximum.
