EASY
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We connect a charge capacitor to an inductor the electric current and charge on the capacitor in the circuit undergoes LC oscillations.

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Important Questions on Alternating Current

MEDIUM
In an L-C oscillator circuit having a completely charged capacitor, with the passage of time _____.
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 L-C Oscillatory circuit having a completely charged capacitor, with passage of time_______
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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EASY
A radio receiver can tune over the frequency range 300kHz to 1200kHz. If the tunable L C circuit has a fixed inductorL=200μH, what must be the range over which the capacitor must be tuned? (You can useπ210 )
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The frequency of output signal becomes_______ times by increasing the value of capacitance 4 times the original in LC oscillation circuit 
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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
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
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
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:
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:
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 consists of an inductance of 0.5mH and a capacitor of 20μF. The equivalent frequency of the circuit is nearly
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An oscillator circuit consists of the inductance of 0.5 mH and a capacitor of 20 μF. The equivalent frequency of the circuit is nearly
HARD
The natural frequency of an L-C circuit is 125000 cycles/s. When a dielectric medium of dielectric constant K is introduced between the plates of the capacitor, the frequency decreases by 25 kHz. The value of K is
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A circuit consists of an inductance of 0.5 mH and a capacitor of 20 μF. The frequency of the LC oscillations is approximately
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Calculate the maximum current in the circuit, if a capacitor of capacitance 1  μ F is charged to a potential of 2 V and is connected in parallel to an inductor of inductance 10-3 H
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The natural frequency of an LC circuit is 125 kHz. When the capacitor is totally filled with a dielectric material, the natural frequency decreases by 25 kHz. Dielectric constant of the material is nearly
HARD
A circuit has a self inductance of 1 henry and carries a current of 2 A. To prevent sparking when the circuit is broken, a capacitor which can withstand 400 volts is used. The least capacitance of the capacitor connected across the switch must be equal to