HARD
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A circuit consists of a coil with inductance L$L$ and an uncharged capacitor of capacitance C. The coil is in a constant uniform magnetic field such that the flux through the coil is ϕ. At time t=0, the magnetic field was abruptly switched off. Let ω0=1/LC and ignore the resistance of the circuit. Then,

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Important Questions on Electromagnetic Induction

EASY

If the instantaneous emf and the instantaneous current equations of an A.C. circuit are respectively.

e=E0sin(ωtπ/6),i=I0sin(ωt+π/6), then the phase difference between voltage and current is :

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
MEDIUM
A series LCR circuit with R=1 , L=1.0 mH, C=0.001 μF is connected to a sinusoidal voltage of peak value 2002V. When the frequency of the supply equals the natural frequency of the circuit, what is the average power transferred to the circuit in one cycle.
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:
EASY
How does the L-C circuit produce oscillation? Explain.
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
HARD

Using the equation

 didt+RLi+1LCidt=VmLeiωt.  for L-C-R circuit, obtain an equation for the complex current  'i' and explain its different terms in the equation. Hence obtain the equation for real current 'i'

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:
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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EASY
Show that the total energy of LC circuit in V=VE12qm2C.
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:
Question Image
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)
EASY
The frequency of output signal becomes_______ times by increasing the value of capacitance 4 times the original in LC oscillation circuit 
HARD

Obtain an expression for the energy associated with an inductor.

MEDIUM
In an L-C Oscillatory circuit having a completely charged capacitor, with passage of time_______
EASY
What is the phase difference between the input and the output voltage in a transistor oscillator circuit?
MEDIUM
In an L-C oscillator circuit having a completely charged capacitor, with the passage of time _____.
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
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:
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