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 […]
Changing magnetic fields can set up current loops in nearby metal bodies and the currents are called as
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(a) eddy currents (b) flux currents (c) alternating currents (d) leaking currents
Correct Answer: […]
The phase difference between the flux linked with a coil rotating in a uniform magnetic field and induced emf produced in it is
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(a) π/2 (b) π/3 (c) (-π/6) (d) π
Correct Answer: […]
The self-inductance of a coil having 500 turns is 50mH. The magnetic flux through the cross-sectional area of the coil while current through it is 8 mA is found to be
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(a) […]
For high frequency a capacity offers
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(a) Less reactance (b) More reactance (c) Zero reactance (d) Infinite reactance
Correct Answer:
Less reactance
Explanation:
No explanation available. Be the first to write the […]
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