An inductor may store energy in [1990]
The current in self inductance L = 40 mH is to beincreased uniformly from 1 amp to 11 amp in 4 milliseconds. The e.m.f. induced in the inductorduring the process is [1990]
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A magnetic field of 2 × 10^{–2} T acts at right anglesto a coil of area 100 cm^{2}, with 50 turns. Theaverage e.m.f. induced in the coil is 0.1 V, when itis removed from the field in t sec. The value of t is
A 100 millihenry coil carries a current of 1A.Energy stored in its magnetic field is [1991]
If the number of turns per unit length of a coil ofsolenoid is doubled, the selfinductance of thesolenoid will [1991]
A rectangular coil of 20 turns and area of crosssection 25 sq. cm has a resistance of 100Ω. If amagnetic field which is perpendicular to the planeof coil changes at a rate of 1000 tesla per second,the current in the coil is [1992]
The total charge induced in a conducting loopwhen it is moved in a magnetic field depend on [1992]
What is the selfinductance of a coil whichproduces 5V when the current changes from 3ampere to 2 ampere in one millisecond? [1993]
If N is the number of turns in a coil, the value ofself inductance varies as [1993]
A conductor of length 0.4 m is moving with aspeed of 7 m/s perpendicular to a magnetic fieldof intensity 0.9 Wb/m2. The induced e.m.f.across the conductor is [1995]
A varying current in a coil changes from 10A tozero in 0.5 sec. If the average e.m.f induced inthe coil is 220V, the selfinductance of the coil is [1995]
Two coils have a mutual inductance 0.005 H.The current changes in the first coil accordingto equation I = I_{0} sin ωt, where I_{0} = 10A and ω = 100π radian/sec. The maximum value of e.m.f.in the second coil is [1998]
In an inductor of selfinductance L = 2 mH,current changes with time according to relationi = t^{2}e^{–t}. At what time emf is zero? [2001]
The magnetic flux through a circuit of resistance R changes by an amount Δφ in a time Δt. Then the total quantity of electric charge Q that passes any point in the circuit during the time Δt is represented by [2004]
As a result of change in the magnetic flux linkedto the closed loop shown in the Fig,
an e.m.f. V volt is induced in the loop. The work done (joules) in taking a charge Q coulomb once along the loop is
[2005]
Two coils of self inductances 2 mH and 8 mH areplaced so close together that the effective fluxin one coil is completely linked with the other.The mutual inductance between these coils is [2006]
A long solenoid has 500 turns. When a currentof 2 ampere is passed through it, the resultingmagnetic flux linked with each turn of thesolenoid is 4 ×10^{–3} Wb. The self inductance ofthe solenoid is [2008]
A rectangular, a square, a circular and an elliptical loop, all in the (x – y) plane, are moving out of a uniform magnetic field with a constant velocity, The magnetic field is directed along the negative z axis direction. The induced emf, during the passage of these loops, out of the field region, will not remain constant for [2009]
A conducting circular loop is placed in a uniformmagnetic field of 0.04 T with its planeperpendicular to the magnetic field. The radiusof the loop starts shrinking at 2 mm/s. The induced emf in the loop when the radius is 2 cmis [2009]
A conducting circular loop is placed in a uniform magnetic field, B = 0.025 T with its plane perpendicular to the loop. The radius of the loop is made to shrink at a constant rate of 1 mm s^{–1}. The induced e.m.f. when the radius is 2 cm, is [2010]
The current i in a coil varies with time as shown in the figure. The variation of induced emf with time would be [2011]
A coil of resistance 400Ω is placed in a magneticfield. If the magnetic flux φ(wb) linked with thecoil varies with time t (sec) as φ = 50t^{2} + 4. Thecurrent in the coil at t = 2 sec is : [2012]
In a coil of resistance 10 Ω, the induced current developed by changing magnetic flux through it, is shown in figure as a function of time. The magnitude of change in flux through the coil in Weber is : [2012M]
A wire loop is rotated in a magnetic field. Thefrequency of change of direction of the inducede.m.f. is [NEET 2013]
A current of 2.5 A flows through a coil ofinductance 5 H. The magnetic flux linked withthe coil is [NEET Kar. 2013]
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105 videos425 docs114 tests
