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प्रश्न
Explain the principle, construction and working of a dc motor.
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उत्तर
A motor is an electrical machine which converts electrical energy into mechanical energy. The principle of working of a DC motor according to Faraday’s laws of electromagnetic induction is that “whenever a current carrying conductor is placed in a magnetic field, it experiences a mechanical force”. The various parts of a DC motor are; Permanent magnets on both sides of a coil which consists of carbon brush and commutator as shown in
Working of electric motor is primarily dependent upon the interaction between magnetic field and current. The direction of this force is given by Fleming’s left hand rule and it’s magnitude is given by F = BIL. Where, B = magnetic flux density, I = current and L = length of the conductor within the magnetic field.
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संबंधित प्रश्न
State Faraday’s laws of electromagnetic induction.
In the following diagram an arrow shows the motion of the coil towards the bar magnet.
(1) State in which direction the current flows, A to B or B to A?
(2) Name the law used to come to the conclusion.
- How would you demonstrate that a momentary current can be obtained by the suitable use of a magnet, a coil of wire and a galvanometer?
- What is the source of energy associated with the current obtained in part (a)?
In which of the following case does the electromagnetic induction occur?
Why does it become more difficult to move a magnet towards a coil when the number of turns in the coil has been increased?
The diagram in shows a coil of several turns of copper wire near a magnet NS. The coil is moved in the direction of arrow shown in the diagram.
- In what direction does the induced current flow in the coil?
- Name the law used to arrive at the conclusion in part (i).
- How would the current in coil be altered if
- the coil has twice the number of turns,
- the coil was made to move three times fast?
The direction of the magnetic field around a straight conductor carrying current can be determined by ______.
Express Faraday-Lenz's law of electromagnetic induction in an equation form.
State two factors on which the magnitude of induced e.m.f. in a coil depend.
The magnetic flux through a coil perpendicular to its plane is varying according to the relation Φ = (5t3 + 4t2 + 2t − 5) Weber. If the resistant of the coil is 5 ohm, then the induced current through the coil at t = 2 sec will be ______.
