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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
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?
A conductor is moved in a varying magnetic field. Name the law which determines the direction of current induced in the conductor.
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 magnet is moved towards a coil (i) quickly (ii) slowly. The induced potential difference.
Two positively charged particles each having charge Q and are d distance apart. A third charge is introduced in midway on the line joining the two. Find nature and magnitude of third charge, so that the system is in equilibrium ______.
Express Faraday-Lenz's law of electromagnetic induction in an equation form.
A conductor in the form of a circular arc of the radius of curvature R subtends an angle Ø at its centre of curvature. If the current in the conduct is I, the magnetic induction at the centre of curvature is ______.
A circular loop is placed in a uniform magnetic field. The total number of magnetic field lines passing normally through the plane of the coil is called ______.
