EASY
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The resonance frequency of LC circuit is

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Important Questions on Electromagnetic Induction

EASY
An oscillating LC circuit consists of a 75 mH inductor and a 1.2 µF capacitor. If the maximum charge to the capacitor is 2.7 µC. The maximum current in the circuit will be _______ mA.
MEDIUM
In an oscillating LC circuit, L=3.00 mH and C=2.70 μF. At t=0 the charge on the capacitor is zero and the current is 2.00 A. The maximum charge that will appear on the capacitor will be
EASY
A capacitor of capacitance 500 μF is charged completely using a DC supply of 100 V. It is now connected to an inductor of inductance 50 mH to form an LC circuit. The maximum current in LC circuit will be _____ A.
MEDIUM
An inductor 20mH, a capacitor 50 μF and a resistor 40 Ω are connected in series across a source of emf V=10 sin 340 t. The power loss in AC  circuit is:
MEDIUM
A fully charged capacitor C with initial charge q0 is connected to a coil of self-inductance L at t=0. The time at which the energy is stored equally between the electric and the magnetic fields is:
EASY
A small signal voltage Vt=V0sinωt is applied across an ideal capacitor C:
EASY
LC oscillations are similar and analogous to the mechanical oscillations of a block attached to a spring. The electrical equivalent of the force constant of the spring is
MEDIUM

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In the above circuit, C= 3 2 μF, R 2 =20 Ω,L= 3 10 H and R 1 =10 Ω. Current in L-R1 path is I1 and in C-R2 path it is I 2 . The voltage of AC source is given by, V=200 2 sin( 100t ) volts. The phase difference between I1 and I2 is:

MEDIUM
An oscillator circuit contains an inductor 0.05 H and a capacitor of capacity 80 μF. When the maximum voltage across the capacitor is 200 V, the maximum current (in amperes) in the circuit is
MEDIUM

At a certain moment, the switch shown in the figure is disconnected. The energy of the oscillations immediately after the switch S is disconnected and at time 0.1 sec from the time switch is disconnected are, respectively

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HARD
An infinite line charge of uniform electric charge density λ lies along the axis of an electrically conducting infinite cylindrical shell of radius R. At time t = 0, the space inside the cylinder is filled with a material of permittivity ε and electrical conductivity σ . The electrical conduction in the material follows Ohm's law. Which one of the following graphs best describes the subsequent variation of the magnitude of current density j(t) at any point in the material?
HARD
A LCR circuit behaves like a clamped harmonic oscillator. Comparing it with a physical spring-mass damped oscillator having damping constant 'b', the correct equivalence would be:
HARD

In the circuit shown below, the key is pressed at time t=0. Which of the following statement(s) is(are) true?
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HARD

An inductor (L=0.03H) and a resistor (R=0.15 ) are connected in series to a battery of 15V E.M.F. in a circuit shown below. The key K1 has been kept closed for a long time. Then at t=0, K1 is opened and key K2 is closed simultaneously. At t=1ms , the current in the circuit will be : Take, e5150

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MEDIUM

In the figure shown, a circuit contains two identical resistors with resistance R=5Ω and an inductance with L=2mH. An ideal battery of 15V is connected in the circuit. What will be the current through the battery long after the switch is closed?

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HARD
In the figure below, the switches S1 and S2 are closed simultaneously at t = 0 and a current starts to flow in the circuit. Both the batteries have the same magnitude of the electromotive force (emf) and the polarities are as indicated in the figure. Ignore mutual inductance between the inductors. The current I in the middle wire reaches its maximum magnitude Imax time t =τ. Which of the following statements is (are) true?

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HARD
A series AC circuit containing an inductor 20 mH, a capacitor 120 μF and a resistor 60 Ω is driven by an AC source of 24 V/50 Hz. The energy dissipated in the circuit in 60 s is:
HARD
In an LC circuit connected to an ac supply, the resonant frequency is 200MHz when a dielectric of thickness 8 mm and dielectric constant 6 is fully inserted between the plates of the capacitor. The resonant frequency becomes 198 MHz when a stress of  995 bar is applied between the plates of the capacitor. The Young's modulus of the dielectric material in Nm-2 is nearly
HARD
In LC circuit the inductance L=40 mH and capacitance C=100 μF. If a voltage Vt=10sin314t is applied to the circuit, the current in the circuit is given as:
HARD
An LCR circuit is equivalent to a damped pendulum. In an LCR circuit the capacitor is charged to Q0 and then connected to the L and R as shown below:
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If a student plots graphs of the square of maximum charge QMax2 on the capacitor with time (t) for two different values L1 and L2(L1>L2) of L then which of the following represents this graph correctly? (plots are schematic and not drawn to scale)