EASY
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A 50 mH coil carries a current of 2 A, the energy stored in J is

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Important Questions on Electromagnetic Induction

EASY
The average emf induced in a coil, when the current in it changes from 2 A to 4 A in 0.05 s, is 8 V. Find the self-inductance of this coil.
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A series L-R circuit is connected to a battery of emf V. If the circuit is switched on at t=0, then the time at which the energy stored in the inductor reaches 1n times of its maximum value, is :
MEDIUM
In an inductor of self-inductance L=2 mH, current changes with time according to relation i=t2e-1. At what time emf is zero?
MEDIUM
Consider a conducting wire of length L bent in the form of a circle of radius R and another conductor of length aa<<R is bent in the form of a square. The two loops are then placed in same plane such that the square loop is exactly at the centre of the circular loop. What will be the mutual inductance between the two loops?
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A long solenoid has 1000 turns. When a current of 4 A flows through it the magnetic flux linked with each turn of the solenoid is 4×10-3 Wb. The self-inductance of the solenoid is:
MEDIUM
Two coaxial coils A and B of radii R1 and R2 are placed in the same plane. R2>R1. If a current is passed through coil B, the coefficient of mutual inductance between the coils is proportional to
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Two inductors L1 and L2 are connected in parallel and a time varying current flows as shown in figure. The ratio ot current i1i2 at any ime t IsQuestion Image

MEDIUM
If a change in current of 0.01 A in one coil produces a change in magnetic flux 2×10-2 weber in another coil, then the mutual inductance between coils is
EASY
A long solenoid has 500 turns. When a current of 2 A is passed through it, the resulting magnetic flux linked with each turn of the solenoid is 4×10-3 Wb, then self-inductance of the solenoid is
EASY
The total number of turns and cross-section area in a solenoid is fixed. However, its length L is varied by adjusting the separation between windings. The inductance of solenoid will be proportional to:
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The self inductance L of a solenoid of length l and area of cross-section A, with a fixed number of turns N increases as
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The primary and the secondary coils of a transformer contains 10 and 100 turns respectively. The primary coil is connected to a battery that supplies a constant voltage of 1.5 V. The voltage across the secondary coil is
EASY
If the inductance of a coil is 1 H, its effective resistance in a DC circuit will be
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Consider two coils of radii r1 and r2, placed at a distance d away as shown in the figure. Assuming the length of the coils l1,l2d with n1,n2 the number of turns per unit length of the two coils respectively, the mutual inductance of the two coils is

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EASY
The mutual inductance between two coils depends upon
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A coil of wire of 1000 turns has self inductance 120 millihenry. The self inductance of a coil 250 turn is
MEDIUM
Two coils 'P' and 'Q' are separated by some distance. When a current of 3 A flows through coil 'P', a magnetic flux of 10-3 Wb passes through 'Q'. No current is passed through 'Q'. When no current passes through 'P' and a current of 2 A passes through 'Q', the flux through 'P' is:
HARD
A small circular loop of wire of radius a  is located at the centre of a much larger circular wire loop of radius b. The two loops are in the same plane. The outer loop of radius b carries an alternating current I=I0cosωt. The emf induced in the smaller inner loop is nearly:
EASY
The self induced emf of a coil is 25 volts. When the current in it is changed at uniform rate from 10 A to 25 A in 1 s , the change in the energy of the inductance is: