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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 Lenz’s Law.
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)?
- Describe briefly one way producing an induced e.m.f?
- State one factor that determines the magnitude of induced e.m.f. in part (a) above.
- What factor determines the direction of induced e.m.f. in part (a) above?
An electron moves on a straight line path XY as shown. The abed is a coil adjacent to the path of electron. What will be the direction of current, if any, induced in the coil?
A coil of 25 turns is pulled in 0.05 s between the poles of a magnet, where its area includes `21 xx106-6 "Wb" "to" 1 xx 10^-6 "Wb"`. The average e.m.f. is ______.
Magnetic flux passing through a coil is initially 6 x 10-4 Wb. It reduces to 10 % of its original value in 't' second. If the e.m.f. induced is 0.54 mV then 't' in second is ____________.
A D.C generator works on the principle of ____________.
Fleming’s left-hand rule is also known as the dynamo rule.
Explain how does the Lenz's law show the conservation of energy in the phenomenon of electromagnetic induction.
