Resonance in a Series LCR Circuit

IMPORTANT

Resonance in a Series LCR Circuit: Overview

This topic covers concepts, such as, Resonance Frequency, Phasor Diagram for Series L-C-R Circuit at Resonance, Current versus Frequency Graph for L-C-R Series Circuit & Power Dissipated at Resonance in Series LCR Circuit etc.

Important Questions on Resonance in a Series LCR Circuit

EASY
IMPORTANT

Graph showing variation of current with frequency of AC source in a series LCR circuit is,

MEDIUM
IMPORTANT

In the following circuit the readings of AC voltmeters and ammeters will be respectively-

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IMPORTANT

The inductance of the oscillatory circuit of the radio station is 10 mH and its capacitance is 0.25 μF. Taking the effect of resistance negligible, wavelength of the broadcasted waves will be (velocity of light =3.0×108 m s-1, π=3.14)

MEDIUM
IMPORTANT

The inductance of the oscillatory circuit of the radio station is 10 mH and its capacitance is 0.25 μF. Taking the effect of resistance negligible, wavelength of the broadcasted waves will be (velocity of light =3.0×108 m s-1, π=3.14)

HARD
IMPORTANT

A source of V=15cosωt V is connected to a series L-C-R circuit having L=10 mHR=3 Ω and C=1 μF. Find the peak value of current at frequency 10 % less than the resonant frequency.

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Which one is the expression of resonant frequency in a series resonant circuit?

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In LCR alternating circuit, R=10 ΩXL=100 Ω and XC=100 Ω. What is the impedance of the circuit in Ohms?

MEDIUM
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A parallel L-C circuit comprises of a 5H inductor and 5μF capacitor. The resonant frequency of the circuit in Hz is 

EASY
IMPORTANT

In the given figure, which point shows the resonant state?
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HARD
IMPORTANT

A circuit draws a power of 550 W from a source of 220 V, 50 Hz. The power factor of the circuit is 0.8 and the current lags in phase behind the potential difference. To make the power factor of the circuit as unity, the capacitance connected with the circuit in series is15×n μF. Find the value of n.

HARD
IMPORTANT

The given figure represents the phasor diagram of a series LCR circuit connected to an ac source. At the instant t't' when the source voltage is given by V=V0cosωt', the current in the circuit will be :

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EASY
IMPORTANT

In the RLC circuit in the figure, R=60 Ω, L=3 mH, C=4 mF, and the source of time varying emf has a peak voltage of 120 V. What should the angular frequency of the source, $\omega$, be to produce the largest current in the resistor?

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If value of R is changed, then :-

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EASY
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The resonance frequency of the tank circuit of an oscillator when L=10π2 mH and C=0.04 μF are connected in parallel is

EASY
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In a series resonant circuit, the AC voltage across resistance R, inductor L and capacitor C are 5 V, 10 V and 10 V, respectively. The AC voltage applied to the current will be

EASY
IMPORTANT

In LCR series circuit, the resonance condition in terms of capacitive reactance (XC) and inductive reactance (XL) is

MEDIUM
IMPORTANT

The inductance of the oscillatory circuit of the radio station is 10 mH and its capacitance is 0.25 μF. Taking the effect of resistance negligible, wavelength of the broadcasted waves will be (velocity of light =3.0×108 m s-1, π=3.14)

EASY
IMPORTANT

A 1Ω resistance, 5 mH coil and 1μF capacitor are joined in series. When a variable frequency alternating current source is joined to this combination, the circuit resonates. If the resistance is halved, the resonance frequency:

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IMPORTANT

A series L-C-R circuit of L=200 mHC=500 μFR=100 Ω is connected to 100 V AC source.

Find-

(i) Frequency at which power factor of circuit is 1.

(ii) Peak value of current at this frequency.

(iii) Quality factor 

MEDIUM
IMPORTANT

Find the resonance frequency of series L-C-R series circuit containing L=0.1 H, C=20 μFR=10 Ω