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प्रश्न
principle of an electric motor ?
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उत्तर
Principle: An electric motor (dc motor) works on the principle that when an electric current is passed through a conductor placed normally in a magnetic field, a force acts on the conductor as a result of which the conductor begins to move and mechanical energy is obtained.
संबंधित प्रश्न
The diagram shows a coil wound around a U-shaped soft iron bar AB.
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- What will be the polarities at A and B if the direction of current is reversed in the circuit?
State two ways of magnetising an iron piece?
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.
Tick the most appropriate answer.
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Name and state the rule by which polarity at the ends of a current carrying solenoid is determined.
Name the material used for making the armature of an electric bell. Give a reason for your answer.
Name the type of transformer shown in fig . What changes will you observe regarding the brightness of the lamp, if
(a) The no. of turns in the secondary is doubled?
(b) The part X of the transformer is removed?
( c) The core of the transformer is made out of copper?
(d ) The A.C. supply is replaced by D.C.?
How does a magnetic field set up by a solenoid change when number of turns are increased?
What are the factors that govern the magnitude of force acting on a current carrying conductor which is freely suspended in a magnetic field?
Write the answer in your words.
How is an electromagnet made?
