Resonance and Q Factor

IMPORTANT

Resonance and Q Factor: Overview

This topic covers concepts, such as, Resonance Frequency, Phasor Diagram for Series L-C-R Circuit at Resonance, Current Versus Frequency Graph for Parallel Resonant Circuit & Half Power Points of Frequency etc.

Important Questions on Resonance and Q Factor

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

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Draw a current versus frequency graph for parallel resonant circuit.

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The current is minimum in _____ LCR circuit?

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The current is minimum in parallel LCR circuit?

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Why the current is minimum in parallel LCR circuit?

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What is the value of current in RLC parallel circuit at resonance frequency

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In series RLC circuit, at resonance condition impedance is purely resistive, and it is equal to _____.

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The resonant frequency of the series LCR circuit is expressed as. fr = 1/2π√(LC)

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What is meant by resonance in an LCR circuit?

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Half power point frequencies for which the power in the circuit is half of the ___________________ power in the circuit.

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The half power point is commonly used definition for the _____ frequency.

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The relationship between power and frequency is inversely proportional to each other.

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What is half power point frequency?

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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)

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In LCR series circuit L=4H, C=36 μF and R=16Ω, then bandwidth of resonance is 

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The bandwidth of resonance in the L-C-R  A.C. circuit is proportional to inductance.

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For an RLC circuit driven with voltage of amplitude vm and frequency ω0=1LC the current exhibits resonance. The quality factor, Q is given by

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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)

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A transmitting station releases waves of wavelength 960 m. A capacitor of 256 μF is used in the resonant circuit. The self inductance of coil necessary for resonance is ×10-8H.

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A series LCR circuit containing a resistance of 120 Ω has an angular resonance frequency 4×105 rad s-1. At resonance the voltage across resistance and inductance are 60 V and 40 V respectively. At frequency ω=X×105 rad s-1 the current in the circuit lags the voltage by 45°. Find the value of X.