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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
How will you make an iron bar electromagnet? Draw a diagram showing the polarities of the electromagnet?
You are given an iron nail, a torch cell, and a long piece of insulated copper wire. With the help of a labelled neat diagram, describe in steps how you will make the nail, an electromagnet.
Name and state the rule by which polarity at the ends of a current carrying solenoid is determined.
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.
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 ______.
Describe briefly one way of producing an induced current in a coil. State one factor that determines the magnitude of induced e.m.f.
How does a magnetic field set up by a solenoid change when strength of current in the solenoid is decreased?
What is a permanent magnet? Give one use of it.
State the principle of a D. C. motor.
What are the factors that govern the magnitude of force acting on a current carrying conductor which is freely suspended in a magnetic field?
