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प्रश्न
Name the material of core in (a) an electric bell, (b) electromagnet, (c) a d.c. motor, (d) an a.c. generator and (e) a transformer.
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उत्तर
Soft iron is used in all.
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संबंधित प्रश्न
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.
Name the material used for making the armature of an electric bell. Give a reason for your answer.
State two factors on which the magnitude of an induced e.m.f. in the secondary coils of a transformer depends.
Answer the following in short.
Name a few common appliances that use electromagnets.
A straight wire is held vertical and current is passed in it in the upward direction. A compass needle is kept near the wire in north of it. How is the needle deflected? What is the change in the deflection of the needle if the current in wire is reversed?
State the purpose of the iron core.
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.
State the factors that can increase the speed of rotation of the coil in a D.C. motor.
Write the answer in your words.
How is an electromagnet made?
