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

EASY
The frequency of output signal becomes_______ times by increasing the value of capacitance 4 times the original in LC oscillation circuit 
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

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 :

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 )
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)
MEDIUM
In an L-C Oscillatory circuit having a completely charged capacitor, with passage of time_______
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
In an L-C oscillator circuit having a completely charged capacitor, with the passage of time _____.
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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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:
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
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
EASY
The square root of the product of inductance and capacitance has the dimension of :
HARD
Explain with the help of a labelled diagram the working of a transistor as an oscillator.
MEDIUM
The tuning circuit of a radio receiver has a resistance of 50 Ω, an inductor of 10 mH and a variable capacitor. 1 MHz radio wave produces a potential difference of 0.1 mV. The values of the capacitor to produce resonance is (Take π2=10)
EASY
How does LC oscillator circuit work ?