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प्रश्न
State two advantages of an electromagnet over a bar magnet.
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उत्तर
Electromagnet can produce a strong magnetic field. Its polarity can be changed by reversing the direction of current.
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?
Tick the most appropriate answer.
Which of the following methods is used to magnetize a magnetic without touching it by a magnet?
State two differences between an electromagnet and a permanent magnet.
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 ______.
State the purpose of the iron core.
State the factors that can increase the speed of rotation of the coil in a D.C. motor.
The primary windings of a step-up transformer are usually made of thicker wire than the secondary. Explain.
State the factors, on which depends the magnitude of the force acting on current carrying conductor, when it is kept in a magnetic field perpendicular to it.
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?
Which magnet will you use?
Iron is to be separated from trash.
