173 + Interview Questions in Resonance & Magnetically Coupled Circuit in Network Theory Page 4 InterviewSolution

151.	Find the bandwidth of the circuit shown below.(a) 1(b) 2(c) 3(d) 4I got this question during an interview.The doubt is from Parallel Resonance topic in division Resonance & Magnetically Coupled Circuit of Network Theory
Answer» Right choice is (C) 3 For explanation: The bandwidth of the circuit is BW = fr/Q. we OBTAINED fr = 7.12 HZ and Q = 2.24. On substituting the given VALUES in the equation we get the bandwidth = 7.12/2.24 = 3.178Hz.

Discussion

152.	Find the quality factor of the following circuit.(a) 2.24(b) 3.34(c) 4.44(d) 5.54This question was addressed to me in my homework.The above asked question is from Parallel Resonance in section Resonance & Magnetically Coupled Circuit of Network Theory
Answer» The correct choice is (a) 2.24 Easy EXPLANATION: The quality factor of the circuit is Q = XL/R = 2πfrL/R. Given F = 7.12 Hz and L = 5H and R = 100. On substituting the given VALUES in the equation we get the quality factor = (6.28×7.12×5)/100 = 2.24.

Discussion

153.	For the circuit shown below, determine its resonant frequency.(a) 6.12(b) 7.12(c) 8.12(d) 9.12I had been asked this question in quiz.My doubt is from Parallel Resonance topic in portion Resonance & Magnetically Coupled Circuit of Network Theory
Answer» Correct answer is (b) 7.12 Easy EXPLANATION: The resonant frequency of the CIRCUIT is fr = 1/(2π√LC). Given L = 5H and C = 100uf. On SUBSTITUTING the given values in the equation we get resonant frequency = 1/(2π√(5×100×10^-6)) = 7.12 Hz.

Discussion

154.	The quality factor of the coil for a series circuit having R = 10Ω, L = 0.1H, C = 10µF.(a) 1(b) 5(c) 10(d) 15This question was posed to me by my college director while I was bunking the class.This key question is from Bandwidth of an RLC Circuit topic in portion Resonance & Magnetically Coupled Circuit of Network Theory
Answer» Correct ANSWER is (C) 10 Easy EXPLANATION: The RESONANT frequency is given by fr = 1/(2π√LC)=1/(2π√(0.1×10×10^-6))=159.2 Hz. The relation between quality factor, resonant frequency and bandwidth is Q = fr/BW = 2πfrL/R = (6.28×159.2×0.1)/10=10.

Discussion

155.	In a series circuit having resistance and inductance, the quality factor is?(a) ωL/R(b) R/ωL(c) ωL(d) RThis question was posed to me in an interview for job.This question is from Bandwidth of an RLC Circuit topic in portion Resonance & Magnetically Coupled Circuit of Network Theory
Answer» CORRECT choice is (a) ωL/R Explanation: QUALITY factor Q = ωL/R. A higher value of CIRCUIT Q results in smaller bandwidth and a lower value of Q CAUSES a LARGER bandwidth.

Discussion

156.	In series circuits, the expression for quality factor is?(a) fr(b) BW(c) fr/BW(d) BW/frThe question was posed to me during an internship interview.I need to ask this question from Bandwidth of an RLC Circuit in chapter Resonance & Magnetically Coupled Circuit of Network Theory
Answer» The correct OPTION is (c) fr/BW To explain I would say: The QUALITY factor is the RATIO of the reactive power in the inductor or capacitor to the true power in the RESISTANCE in series with the coil or capacitor. The expression of quality factor is Q = fr/BW.

Discussion

157.	If a series circuit contains resistor and capacitor, the expression for quality factor is?(a) C(b) ωRC(c) ωC(d) 1/ωRCThis question was addressed to me during an interview for a job.My question is from Bandwidth of an RLC Circuit topic in division Resonance & Magnetically Coupled Circuit of Network Theory
Answer» RIGHT option is (d) 1/ωRC For explanation: The expression of quality FACTOR is Q = 1/ωRC. The RATIO of voltage across EITHER L or C to the voltage applied the resonance can be defined as magnification.

Discussion

158.	The expression for bandwidth is?(a) R/πL(b) R/2πL(c) R/4πL(d) R/8πLThis question was addressed to me in an interview.This key question is from Bandwidth of an RLC Circuit topic in portion Resonance & Magnetically Coupled Circuit of Network Theory
Answer» The correct choice is (b) R/2πL Best explanation: The bandwidth of any SYSTEM is the RANGE of frequencies for which the CURRENT or output voltage is equal to 70.7% of its value at the resonant FREQUENCY. The expression of bandwidth is BW = f2 – F1 = R/2πL.

Discussion

159.	The expression for upper half power frequency is?(a) (R+√(x^2+4LC))/4πL(b) (R-√(x^2+4LC))/4πL(c) (–R-√(x^2+4LC))/4πL(d) (-R+√(x^2+4LC))/4πLThis question was posed to me in homework.My question is taken from Bandwidth of an RLC Circuit in portion Resonance & Magnetically Coupled Circuit of Network Theory
Answer» The correct answer is (a) (R+√(x^2+4LC))/4πL Explanation: The NARROWER the bandwidth the greater the selectivity. At upper half power frequency, XC < XL => -(1/2πf2C)+2πf2L=R. F2 = (R+√(x^2+4LC))/4πL.

Discussion

160.	The expression for lower half power frequency is?(a) (-R+√(x^2+4LC))/4πL(b) (–R-√(x^2+4LC))/4πL(c) (R-√(x^2+4LC))/4πL(d) (R+√(x^2+4LC))/4πLI had been asked this question in an international level competition.My doubt stems from Bandwidth of an RLC Circuit in chapter Resonance & Magnetically Coupled Circuit of Network Theory
Answer» CORRECT answer is (a) (-R+√(x^2+4LC))/4πL To explain: Selectivity indicates how WELL a RESONANT circuit responds to a certain frequency and eliminates all other frequencies. At lower power frequency, XC > XL(1/2πf1C)-2πf1L=R. f1 = (-R+√(x^2+4LC))/4πL.

Discussion

161.	At upper half power frequency, the expression for power (P2) is?(a) I^2maxR(b) (I^2maxR)/2(c) (I^2maxR)/4(d) (I^2maxR)/8I have been asked this question in unit test.I need to ask this question from Bandwidth of an RLC Circuit topic in division Resonance & Magnetically Coupled Circuit of Network Theory
Answer» The correct answer is (b) (I^2maxR)/2 The explanation is: At upper half POWER frequency, the expression for power (P2) is P2 =(I^2maxR)/2. The RESPONSE curve is ALSO called the selectivity curve of the circuit.

Discussion

162.	Determine the resonant frequency for the specifications: R = 10Ω, L = 0.1H, C = 10µF.(a) 157(b) 158(c) 159(d) 160I have been asked this question in semester exam.This interesting question is from Bandwidth of an RLC Circuit in section Resonance & Magnetically Coupled Circuit of Network Theory
Answer» Correct OPTION is (c) 159 The best explanation: The frequency at which the resonance OCCURS is CALLED RESONANT frequency. The expression of the resonant frequency is given by fr = 1/(2π√LC). On substituting the given values we GET resonant frequency = 1/(2π√(0.1×10×10^-6))=159.2 Hz.

Discussion

163.	The expression of power (P1) at lower half power frequency is?(a) (I^2maxR)/8(b) (I^2maxR)/4(c) (I^2maxR)/2(d) I^2maxRThe question was posed to me by my college director while I was bunking the class.Query is from Bandwidth of an RLC Circuit topic in section Resonance & Magnetically Coupled Circuit of Network Theory
Answer» Right choice is (C) (I^2maxR)/2 The explanation is: The upper and lower cut-off FREQUENCIES are sometimes called the HALF-power frequencies,. At these frequencies the power from the source is half of the power delivered at the RESONANT frequency. The expression of power (P1) at lower half power frequency is P1 = (I^2maxR)/2.

Discussion

164.	Determine the resonant frequency (kHz) for the circuit shown below.(a) 2.25(b) 22.5(c) 225(d) 2250I got this question in an online interview.Question is from Series Resonance topic in portion Resonance & Magnetically Coupled Circuit of Network Theory
Answer» RIGHT option is (a) 2.25 For EXPLANATION: The expression of RESONANT frequency is resonant frequency fr = 1/(2π√LC). Given L = 0.5mH and C = 10uF. On substituting in the equation we GET resonant frequency fr = 1/(2π√(10×10^-6)×0.5×10^-3)) = 2.25kHz.

Discussion

165.	What is the value of the impedance at resonance in the circuit shown below?(a) 25(b) 50(c) 75(d) 100This question was addressed to me in final exam.This intriguing question comes from Series Resonance topic in chapter Resonance & Magnetically Coupled Circuit of Network Theory
Answer» The CORRECT CHOICE is (b) 50 The explanation: We know that at resonance the value of IMPEDANCE at resonance. So Z = R. Given R = 50Ω. On SUBSTITUTING in the equation we get Z = 50Ω.

Discussion

166.	In series RLC circuit, the voltage across capacitor and inductor are ______ with each other.(a) in phase(b) 180⁰ out of phase(c) 90⁰ out of phase(d) 45⁰ out of phaseThe question was asked in unit test.Query is from Series Resonance topic in division Resonance & Magnetically Coupled Circuit of Network Theory
Answer» The correct choice is (B) 180⁰ out of phase The EXPLANATION is: In series RLC circuit, the VOLTAGE ACROSS capacitor and inductor are 180⁰ out of phase with each other. The frequency at which the resonance occurs is called RESONANT frequency.

Discussion

167.	For the circuit shown in figure determine the capacitive reactance at resonance.(a) 15(b) 20(c) 25(d) 30I have been asked this question in examination.I would like to ask this question from Series Resonance topic in section Resonance & Magnetically Coupled Circuit of Network Theory
Answer» CORRECT option is (c) 25 Explanation: We KNOW at resonance, capacitive REACTANCE is equal to the INDUCTIVE reactance that is XL = XC. Given inductive reactance XL = 25. On substituting in the equation we get XC = 25Ω.

Discussion

168.	The expression of resonant frequency in a series resonant circuit is?(a) 1/(2π√C)(b) 1/( 2π√L)(c) 2π√LC(d) 1/(2π√LC)I have been asked this question in an online quiz.The question is from Series Resonance in section Resonance & Magnetically Coupled Circuit of Network Theory
Answer» The correct OPTION is (d) 1/(2π√LC) Explanation: The expression of resonant frequency is resonant frequency = 1/(2π√LC). In a SERIES RLC circuit resonance MAY be produced by VARYING the frequency, keeping L and C constant.

Discussion

169.	At resonant frequency, the voltage across capacitor is _______ the voltage across inductor.(a) greater than(b) less than(c) greater than or equal to(d) equal toThe question was posed to me during an interview.My doubt is from Series Resonance topic in chapter Resonance & Magnetically Coupled Circuit of Network Theory
Answer» Correct option is (d) equal to For EXPLANATION I would say: At resonant frequency, the voltage across capacitor is equal to the voltage across inductor. If ONE of the parameters of the series RLC circuit is varied in such a way that the current in the circuit is in PHASE with the applied voltage, then the circuit is said to be in resonance.

Discussion

170.	The voltage across the LC combination in a series RLC circuit is?(a) 0(b) 1(c) 2(d) 3The question was asked in an interview.My enquiry is from Series Resonance in division Resonance & Magnetically Coupled Circuit of Network Theory
Answer» RIGHT OPTION is (a) 0 The best explanation: Since the VOLTAGE across capacitor and inductor are 180⁰ out of phase with each other, the voltage across the LC combination in a series RLC circuit is 0V.

Discussion

171.	As XL = XC in a series resonance circuit, the impedance is_________(a) purely capacitive(b) purely inductive(c) purely resistive(d) capacitive and inductiveThe question was posed to me in a job interview.My question is taken from Series Resonance topic in section Resonance & Magnetically Coupled Circuit of Network Theory
Answer» Right option is (c) purely RESISTIVE The explanation is: As XL = XC in a series RESONANCE circuit, the impedance is purely resistive. In a series RLC circuit the current lags behind or LEADS the applied voltage depending on the values of XL and XC.

Discussion

172.	In a series resonance circuit, series resonance occurs when?(a) XL = 1(b) XC = 1(c) XL = XC(d) XL = -XCThis question was addressed to me during an interview for a job.The question is from Series Resonance in division Resonance & Magnetically Coupled Circuit of Network Theory
Answer» Right CHOICE is (c) XL = XC To elaborate: In a series resonance CIRCUIT, series resonance occurs when CAPACITIVE reactance is EQUAL to the inductive reactance that is XL = XC.

Discussion

173.	The circuit is said to be in resonance if the current is ____ with the applied voltage.(a) in phase(b) out of phase(c) 45⁰ out of phase(d) 90⁰ out of phaseThe question was asked by my school teacher while I was bunking the class.This interesting question is from Series Resonance topic in portion Resonance & Magnetically Coupled Circuit of Network Theory
Answer» The correct answer is (a) in phase Easy EXPLANATION: The circuit is said to be in RESONANCE if the current is in phase with the APPLIED voltage and not if the current is out of phase with the applied voltage. The study of resonance is very useful particularly in the AREA of COMMUNICATIONS.

Discussion

Explore topic-wise InterviewSolutions in .

Find the bandwidth of the circuit shown below.(a) 1(b) 2(c) 3(d) 4I got this question during an interview.The doubt is from Parallel Resonance topic in division Resonance & Magnetically Coupled Circuit of Network Theory

Find the quality factor of the following circuit.(a) 2.24(b) 3.34(c) 4.44(d) 5.54This question was addressed to me in my homework.The above asked question is from Parallel Resonance in section Resonance & Magnetically Coupled Circuit of Network Theory

For the circuit shown below, determine its resonant frequency.(a) 6.12(b) 7.12(c) 8.12(d) 9.12I had been asked this question in quiz.My doubt is from Parallel Resonance topic in portion Resonance & Magnetically Coupled Circuit of Network Theory

In a series circuit having resistance and inductance, the quality factor is?(a) ωL/R(b) R/ωL(c) ωL(d) RThis question was posed to me in an interview for job.This question is from Bandwidth of an RLC Circuit topic in portion Resonance & Magnetically Coupled Circuit of Network Theory

In series circuits, the expression for quality factor is?(a) fr(b) BW(c) fr/BW(d) BW/frThe question was posed to me during an internship interview.I need to ask this question from Bandwidth of an RLC Circuit in chapter Resonance & Magnetically Coupled Circuit of Network Theory

The expression for bandwidth is?(a) R/πL(b) R/2πL(c) R/4πL(d) R/8πLThis question was addressed to me in an interview.This key question is from Bandwidth of an RLC Circuit topic in portion Resonance & Magnetically Coupled Circuit of Network Theory

Determine the resonant frequency for the specifications: R = 10Ω, L = 0.1H, C = 10µF.(a) 157(b) 158(c) 159(d) 160I have been asked this question in semester exam.This interesting question is from Bandwidth of an RLC Circuit in section Resonance & Magnetically Coupled Circuit of Network Theory

Determine the resonant frequency (kHz) for the circuit shown below.(a) 2.25(b) 22.5(c) 225(d) 2250I got this question in an online interview.Question is from Series Resonance topic in portion Resonance & Magnetically Coupled Circuit of Network Theory

What is the value of the impedance at resonance in the circuit shown below?(a) 25(b) 50(c) 75(d) 100This question was addressed to me in final exam.This intriguing question comes from Series Resonance topic in chapter Resonance & Magnetically Coupled Circuit of Network Theory

For the circuit shown in figure determine the capacitive reactance at resonance.(a) 15(b) 20(c) 25(d) 30I have been asked this question in examination.I would like to ask this question from Series Resonance topic in section Resonance & Magnetically Coupled Circuit of Network Theory

The expression of resonant frequency in a series resonant circuit is?(a) 1/(2π√C)(b) 1/( 2π√L)(c) 2π√LC(d) 1/(2π√LC)I have been asked this question in an online quiz.The question is from Series Resonance in section Resonance & Magnetically Coupled Circuit of Network Theory

The voltage across the LC combination in a series RLC circuit is?(a) 0(b) 1(c) 2(d) 3The question was asked in an interview.My enquiry is from Series Resonance in division Resonance & Magnetically Coupled Circuit of Network Theory

In a series resonance circuit, series resonance occurs when?(a) XL = 1(b) XC = 1(c) XL = XC(d) XL = -XCThis question was addressed to me during an interview for a job.The question is from Series Resonance in division Resonance & Magnetically Coupled Circuit of Network Theory