Two identical circular coils A and B are kept on a horizontal tube side by side without touching each other. If the current in the coil A increases with time, in response, the coil B […]
The induced emf in a coil of 10 H inductance in which current varies from 9 A to 4 A in 0.2 s is
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(a) 200 V (b) 250 V (c) 300 V […]
If a charge in current of 0.01 A in one coil produces a change in magnetic flux of 1.2 x 10⁻² Wb in the outer coil, then the mutual inductance of the coils in henry […]
The current in a self-inductance L=40 mH is to be increased uniformly from 1A to 11A in 4 ms. The emf indued in the inductor during the process is
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(a) 100 V (b) […]
Magnetic flux φ (in weber) linked with a closed circuit of resistance 10 Ω varies with time t (in sec) as φ=5t²-4t+1. The induced e.m.f. in the circuit at 0.2 sec is
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A very small circular loop of radius a is initially (at t=0) coplanar and concentric with a much larger fixed circular loop of radius b. A constant current I flows in the larger loop. The […]
Find out the e.m.f. produced when the current changes from 0 to 1 A in 10 sec. Given L=10 µH.
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(a) 1 V (b) 1 µV (c) 1 mV (d) 0.1 V
The initial rate of increase of current, when a battery of emf 6 V is connected in series with an inductance of 2H and resistance 12Ω, is
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(a) 0.5 As⁻¹ (b) 1 […]
Large transformers, when used for some time, become hot and are cooled by circulating oil. The heating of transformer is due to
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(a) Both the hysterisis loss and heating effect of current […]
The identical loops of copper and aluminium are moving with the same speed in a magnetic field. Which of the following statements is true?
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(a) Induced emf and induced current are same […]
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