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प्रश्न
State the energy change that takes’place in a D. C. motor.
उत्तर
The energy change that takes place in a D. C. motor is from electrical energy into mechanical energy.
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संबंधित प्रश्न
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 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.
Name the material used for making the armature of an electric bell. Give a reason for your answer.
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.
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 a soft iron core is inserted inside solenoid?
Why is soft iron generally used as the core of the electromagnet?
State two advantages of an electromagnet over a bar magnet.
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?
(i) A straight wire conductor passes vertically through a piece of cardboard sprinkled with iron filings. Copy the diagram and show the setting of iron filings when a current is passed through the wire in the upward direction and the cardboard is tapped gently. Draw arrows to represent the direction of the magnetic field lines.
(ii) Name the law which helped you to find the direction of the magnetic field lines.
