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प्रश्न
State the principle of a D. C. motor.
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उत्तर
It is based 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. The direction of the force is obtained with the help of Fleming’s left hand rule.
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.
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 of core in (a) an electric bell, (b) electromagnet, (c) a d.c. motor, (d) an a.c. generator and (e) a transformer.
Complete the following sentence :
On reserving the direction of current in a wire, the magnetic field produced by it gets _____.
State the purpose of the iron core.
State the condition when an electric charge can give rise to a magnetic field.
What energy conversion takes place during the working of a d c motor?
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 important properties (or characteristics) of magnetic lines of force around a straight conductor.
