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NEET UG PHYSICS MCQ: ELECTRO MAGNETIC INDUCTION
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Which of the following phenomena is utilised in the construction of mouth piece of a telephone now a days?
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Correct option: C
Change of resistance with pressure
Option C (Change of resistance with pressure) is correct because carbon microphones, commonly used in telephone mouthpieces, operate on the principle that pressure changes the resistance of carbon granules.
More Questions from ELECTRO MAGNETIC INDUCTION
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Assertion (A): Whenever the magnetic flux linked with a closed coil changes there will be an induced emf as well as an induced current.
Reason (R): According to Faraday, the induced emf is inversely proportional to the rate of change of magnetic flux linked with a coil. The coefficient of mutual inductance of two coils is . If the current flowing in one is , then the induced e.m.f. in the second coil will be The induced emf cannot be produced by: Consider the statements:
(I)If magnetic field, , then magnetic flux is also zero.
(II)If magnetic flux, then magnetic field is also zero. The coefficient of self inductance of a solenoid is 0.18 mH. If a rod of soft iron of relative permeability 900 is inserted, then the coefficient of self inductance (in mH ) will become nearly: A uniformly wound solenoidal coil of self inductance H and resistance 6 Ω is broken up into two identical coils. These identical coils are then connected in parallel across a 12 V battery of negligible resistance. The time constant of the current in the circuit
Reason (R): According to Faraday, the induced emf is inversely proportional to the rate of change of magnetic flux linked with a coil. The coefficient of mutual inductance of two coils is . If the current flowing in one is , then the induced e.m.f. in the second coil will be The induced emf cannot be produced by: Consider the statements:
(I)If magnetic field, , then magnetic flux is also zero.
(II)If magnetic flux, then magnetic field is also zero. The coefficient of self inductance of a solenoid is 0.18 mH. If a rod of soft iron of relative permeability 900 is inserted, then the coefficient of self inductance (in mH ) will become nearly: A uniformly wound solenoidal coil of self inductance H and resistance 6 Ω is broken up into two identical coils. These identical coils are then connected in parallel across a 12 V battery of negligible resistance. The time constant of the current in the circuit