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प्रश्न
State Faraday’s laws of electromagnetic induction.
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उत्तर १
First law: Whenever there is a change of magnetic flux in a closed circuit, an induced emf is produced in the circuit. This law is a qualitative law as it only indicates the characteristics of induced emf.
Second law: The magnitude of the induced emf produced in the circuit is directly proportional to the rate of change of the magnetic flux linked with the circuit. This law is known as the quantitative law, as it gives the magnitude of the induced emf.
उत्तर २
Faraday’s First Law: Whenever the magnetic flux linked with a circuit changes, an emf is induced in the circuit.
Faraday’s Second Law: The magnitude of the induced emf is equal to the rate of change of magnetic flux.
e = `-(d phi)/dt`
For a coil of N turns:
e = `-N (d phi)/dt`
Negative sign indicates Lenz’s law (direction opposes cause).
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संबंधित प्रश्न
State Lenz’s Law.
- 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?
In which of the following case does the electromagnetic induction occur?
A conductor is moved in a varying magnetic field. Name the law which determines the direction of current induced in the conductor.
What is Lenz’s law?
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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?
Explain the principle, construction and working of a dc motor.
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State two factors on which the magnitude of induced e.m.f. in a coil depend.
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