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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

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

The frequency of output signal becomes_______ times by increasing the value of capacitance

4

times the original in LC oscillation circuit

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

In an oscillating

L C

circuit,

L = 3.00 mH

and

C = 2.70 μ F

. 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

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

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

$e = E 0 \sin (ω t - π / 6), i = I 0 \sin (ω t + π / 6),$ then the phase difference between voltage and current is :

EASY

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

A radio receiver can tune over the frequency range

300 kHz

1200 kHz

. If the tunable

L C

circuit has a fixed inductor

L = 200 μ H

, what must be the range over which the capacitor must be tuned? (You can use

π^{2} \approx 10

)

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

A fully charged capacitor

C

with initial charge

q_{0}

is connected to a coil of self-inductance

L

t = 0 .

The time at which the energy is stored equally between the electric and the magnetic fields is:

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

In an L-C Oscillatory circuit having a completely charged capacitor, with passage of time_______

EASY

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

L C

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

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

In an L-C oscillator circuit having a completely charged capacitor, with the passage of time _____.

HARD

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

An LCR circuit is equivalent to a damped pendulum. In an LCR circuit the capacitor is charged to

Q_{0}

and then connected to the L and R as shown below:
Question Image

If a student plots graphs of the square of maximum charge

(Q_{M a x}^{2})

on the capacitor with time (t) for two different values

L_{1}

and

L_{2} (L_{1} > L_{2})

of L then which of the following represents this graph correctly? (plots are schematic and not drawn to scale)

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

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

Question Image

HARD

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

In an LC circuit connected to an ac supply, the resonant frequency is

200 MHz

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

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

L C R

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

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

L C

circuit the inductance

L = 40 mH

and capacitance

C = 100 μF .

If a voltage

V (t) = 10 s i n (314 t)

is applied to the circuit, the current in the circuit is given as:

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

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

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

The tuning circuit of a radio receiver has a resistance of

50 Ω

, an inductor of

10 m H

and a variable capacitor.

1 M H z

radio wave produces a potential difference of

0.1 m V

. The values of the capacitor to produce resonance is (Take

π^{2} = 10

)

EASY

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

How does LC oscillator circuit work ?

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

Choose the wrong statement.

EASY

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

Let

L

denote the self-inductance of coil which is in series with a capacitor of capacitance

C

. Which of the following has the unit second?

HARD

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

Show that the total energy of LC oscillations is conserved.

EASY

Physics>Electricity and Magnetism>Alternating Current>LC Oscillations

What are the different properties of LC circuit?

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

Important Questions on Alternating Current

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