55 + Interview Questions in Single Phase Series Circuits in Basic Electrical Engineering Page 1 InterviewSolution

1.	What is the relation between reactance, resistance and impedance?(a) Z=R+jX(b) Z=R+X(c) Z=R-X(d) Z=R-jXI got this question in an interview.My doubt stems from Current and Voltage in a Capacitive Circuit topic in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» Correct CHOICE is (a) Z=R+jX The BEST EXPLANATION: The combination of resistance and REACTANCE is known as impedance.Z=R+jX Where Z is impedance, R is resistance and X is reactance.

Discussion

2.	For an RL circuit, the phase angle is always ________(a) Positive(b) Negative(c) 0(d) 90The question was asked in a national level competition.My doubt stems from Resistance and Inductance in Series in chapter Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct option is (b) NEGATIVE The explanation is: For a series RESISTANCE and INDUCTANCE circuit the phase angle is ALWAYS a negative value because the current will always lag the VOLTAGE.

Discussion

3.	What is the resonance frequency of ac circuit?(a) 1/√LC(b) √(L/C)(c) √LC(d) LCI got this question by my college professor while I was bunking the class.Question is taken from Alternating Current in a Capacitive Circuit in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» CORRECT OPTION is (a) 1/√LC Easiest EXPLANATION: At RESONANCE, XL=XC ωL=1/ωC ω=1/√LC.

Discussion

4.	What is the frequency in resonance condition?(a) Minimum(b) Maximum(c) Cannot be determined(d) ZeroThe question was posed to me by my college director while I was bunking the class.Enquiry is from Alternating Current in a Capacitive Circuit topic in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct option is (b) Maximum The BEST I can EXPLAIN: At resonance condition, the frequency is maximum since the inductive reactance is equal to the capacitive reactance. XL=XC.

Discussion

5.	Find the total voltage applied in a series RLC circuit when i=3mA, VL=30V, VC=18V and R=1000 ohms.(a) 3.95V(b) 51V(c) 32.67V(d) 6.67VThis question was addressed to me in a national level competition.My query is from Alternating Current in an RLC Circuit topic in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» Right answer is (B) 51V To EXPLAIN I WOULD say: Total VOLTAGE= VR+VL+VC. VR=1000310^-3=3V. THEREFORE, total voltage = 30+18+3=51V.

Discussion

6.	The combination of resistance and reactance known as ___________(a) Susceptance(b) Impedance(c) Conductance(d) AdmittanceThe question was posed to me at a job interview.This interesting question is from Current and Voltage in a Capacitive Circuit in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» Right choice is (b) Impedance For explanation: The combination of resistance and reactance is known as impedance. It is EQUIVALENT resistance of an RLC alternating CIRCUIT.

Discussion

7.	What is the resonance condition?(a) When XL>XC(b) When XL
Answer» Correct answer is (c) When XL=XC Easiest explanation: The current is in phase with the voltage when the capacitive REACTANCE is in equal to the INDUCTIVE reactance. This is KNOWN as resonance condition.

Discussion

8.	What is tanϕ for RC circuit?(a) XC/R(b) XL/R(c) R/Z(d) Z/RI have been asked this question during an online exam.Query is from Alternating Current in a Capacitive Circuit in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» The CORRECT option is (a) XC/R For EXPLANATION: From the impedance triangle, HEIGHT gives CAPACITIVE reactance and BASE gives resistance. tanϕ=XC/R.

Discussion

9.	What is impedance at resonance?(a) maximum(b) minimum(c) zero(d) cannot be determinedI got this question by my school teacher while I was bunking the class.My query is from Alternating Current in a Capacitive Circuit in chapter Single Phase Series Circuits of Basic Electrical Engineering
Answer» RIGHT answer is (b) minimum The EXPLANATION is: At resonance, XL=XC Z^2=R^2+(XL-XC)^2 Z=RSo Z is minimum at resonance.

Discussion

10.	In an RLC series phasor, we start drawing the phasor from which quantity?(a) Voltage(b) Resistance(c) Impedance(d) CurrentThe question was asked in an internship interview.This interesting question is from Alternating Current in an RLC Circuit in chapter Single Phase Series Circuits of Basic Electrical Engineering
Answer» Correct OPTION is (d) CURRENT Best explanation: In an RLC series phasor diagram, we start drawing the phasor from the QUANTITY which is common to all THREE COMPONENTS, that is the current.

Discussion

11.	If in an alternating current circuit, capacitance of 30 µF is connected to a supply of 200V,50Hz. Find the current in the circuit.(a) 1.38 A(b) 1.89 A(c) 1.74 A(d) 0.89 AThe question was posed to me during an interview.I need to ask this question from Resistance and Capacitance in Series topic in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» The CORRECT CHOICE is (a) 1.38 A Explanation: XC=1/(2πfC)=106.1 I=V/XC=200/106.1=1.89 A.

Discussion

12.	In ac circuit, resistance 5 ohm is connected with a capacitor having capacitive reactance 12 ohm. Supply of 260 V is connected to the circuit. Calculate the voltage across a capacitor.(a) 300 V(b) 200 V(c) 240 V(d) 100 VThis question was addressed to me by my college director while I was bunking the class.This is a very interesting question from Resistance and Capacitance in Series in chapter Single Phase Series Circuits of Basic Electrical Engineering
Answer» CORRECT choice is (c) 240 V Easiest EXPLANATION: Z^2=R^2+XC^2 SUBSTITUTING the values we get Z^2 = 5^2 + 12^2 Z^2 = 169 Z=13 Ω. I = V/Z = 260/13=20 A. VC=iXC=20*12=240 V.

Discussion

13.	If in an alternating current circuit, impedance is 26 ohm, capacitive reactance is 24 ohm, what is the resistance?(a) 25 ohm(b) 10 ohm(c) 12 ohm(d) 23 ohmThe question was asked in semester exam.The above asked question is from Resistance and Capacitance in Series in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» RIGHT ANSWER is (B) 10 ohm The best I can EXPLAIN: Z=26Ω, XC=24Ω Z^2=R^2+XC^2Substituting the values we get, 26^2 = R^2 + 24^2 676 = R^2 + 576 R^2 = 100 R=10 Ω.

Discussion

14.	In ac circuit, resistance 5 ohm is connected with capacitor having capacitive reactance 12 ohm. Supply of 260 V is connected to the circuit. Calculate the current in the circuit.(a) 40 A(b) 10 A(c) 20 A(d) 30 AThis question was posed to me in a job interview.My question is from Resistance and Capacitance in Series in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» Right choice is (C) 20 A The EXPLANATION is: Z^2=R^2+XC^2 SUBSTITUTING the VALUES we get Z^2 = 5^2 + 12^2 Z^2 = 169 Z=13 Ω. I=V/Z = 260/13=20 A.

Discussion

15.	Can capacitor fully charge using alternating current?(a) yes(b) no(c) may or may not(d) depend on value of capacitanceThis question was addressed to me during an interview.This is a very interesting question from Current and Voltage in a Capacitive Circuit in chapter Single Phase Series Circuits of Basic Electrical Engineering
Answer» Correct choice is (a) yes Best explanation: No, the CAPACITOR cannot be fully CHARGED using alternating current because as soon as the capacitor charges, the alternating current reverses its polarity thereby discharging it.

Discussion

16.	When is tanφ positive?(a) When inductive reactance is less than capacitive reactance(b) When inductive reactance is greater than capacitive reactance(c) When inductive reactance is equal to capacitive reactance(d) When inductive reactance is zeroI got this question in examination.I'd like to ask this question from Alternating Current in an RLC Circuit in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct ANSWER is (b) When inductive reactance is greater than CAPACITIVE reactance For EXPLANATION I would say: tanφ is positive when inductive reactance is greater than capacitive reactance because CURRENT will lag the VOLTAGE.

Discussion

17.	What is the correct expression for the phase angle in an RLC series circuit?(a) φ=tan^-1(XL-XC)/R(b) φ=tan^-1 (XL+XC)/R(c) φ=tan(XL-XC)/R(d) φ=tan^-1 (XL-XC)The question was posed to me in examination.The doubt is from Alternating Current in an RLC Circuit topic in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» RIGHT ANSWER is (a) φ=tan^-1(XL-XC)/R To elaborate: from the IMPEDANCE TRIANGLE we get tanφ=(XL-XC)/R. Hence φ=tan^-1 (XL-XC)/R.

Discussion

18.	What is the resistance offered by a capacitor?(a) Susceptance(b) Conductance(c) Admittance(d) ReactanceThis question was posed to me in exam.I'd like to ask this question from Current and Voltage in a Capacitive Circuit topic in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» Correct CHOICE is (d) Reactance To ELABORATE: Resistance offered to alternating current by inductor or capacitor is known as reactance which is EQUIVALENT to resistance of RESISTOR.

Discussion

19.	Which type of current can be stored in a capacitor?(a) Alternating current(b) Direct current(c) Both alternating current and direct current(d) Neither alternating current nor direct currentI have been asked this question by my college professor while I was bunking the class.This intriguing question originated from Current and Voltage in a Capacitive Circuit in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct option is (b) Direct current For explanation I WOULD SAY: Only direct current can be STORED in the capacitor. Capacitor cannot be FULLY charged using alternating current because as soon as the capacitor charges, alternating current reverses its polarity thereby discharging it. So, we cannot STORE ac current in capacitor.

Discussion

20.	If in an alternating current circuit, capacitance C is connected to a supply of 200V,50Hz. Current in the circuit is 1.89 A. Find the capacitance C.(a) 30 µF(b) 20 µF(c) 10 µF(d) 15 µFThe question was posed to me in an international level competition.My enquiry is from Resistance and Capacitance in Series in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct CHOICE is (a) 30 µF To explain I would say: XC= V/I = 200/1.89 = 106.1 Ω.XC=1/(2πfC)Substituting the VALUES we GET C = 30 µF.

Discussion

21.	A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a x V 50Hz sinusoidal supply. The current in the circuit is 8.2A. Calculate the value of x.(a) 10V(b) 50V(c) 100V(d) 120VI had been asked this question during an online exam.My query is from Resistance and Inductance in Series in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct CHOICE is (C) 100V To explain: XL=2πFL= 10 ohm.Z^2=(R^2+XL^2) Therefore, the total impedance Z = 12.2ohm. V=IZ, therefore V = 12.28.2 = 100V.

Discussion

22.	What is the value of impedance at resonance?(a) XL(b) XC(c) R(d) 0The question was posed to me during an online interview.The question is from Alternating Current in a Capacitive Circuit topic in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» The CORRECT option is (c) R Easy explanation: At RESONANCE, XL=XC Z^2=R^2+(XL-XC)^2 Z=RSo Z is MINIMUM at resonance.

Discussion

23.	What is φ in terms of voltage?(a) φ=cos^-1V/VR(b) φ=cos^-1V*VR(c) φ=cos^-1VR/V(d) φ=tan^-1V/VRThe question was asked in quiz.The query is from Resistance and Inductance in Series in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» RIGHT choice is (c) φ=cos^-1VR/V Easiest EXPLANATION: From the voltage TRIANGLE, we get cosφ= VR/V. Hence φ=cos^-1VR/V.

Discussion

24.	In an RLC circuit, which of the following is always used as a vector reference?(a) Voltage(b) Resistance(c) Impedance(d) CurrentI have been asked this question in final exam.My enquiry is from Alternating Current in an RLC Circuit in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» The CORRECT option is (a) VOLTAGE To explain I WOULD say: In an RLC circuit, the voltage is always used as a reference and according to the PHASE of the voltage, the phase of the other parameters is DECIDED.

Discussion

25.	Which of the following is not ac waveform?(a) sinusoidal(b) square(c) constant(d) triangularThe question was asked by my college director while I was bunking the class.My question comes from Alternating Current in an RLC Circuit topic in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct answer is (C) constant Explanation: AC waveforms are those which periodically changes polarity with time.Sinusoidal wave, SQUARE wave, triangular wave CHANGE their polarity at regular intervals so they are ac wavefoms. Constant wave DOESNOT change its polarity so it is not an ac WAVEFORM.

Discussion

26.	In ac circuit, resistance 5 ohm is connected with capacitor having capacitive reactance 12 ohm. Supply of 260 V is connected to the circuit. Calculate the voltage across resistance.(a) 300 V(b) 200 V(c) 240 V(d) 100 VThis question was posed to me in an internship interview.I'm obligated to ask this question of Resistance and Capacitance in Series topic in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» RIGHT ANSWER is (d) 100 V The BEST EXPLANATION: Z^2=R^2+XC^2Substituting the values we get Z^2 = 5^2 + 12^2 Z^2 = 169 Z=13 Ω. I = V/Z = 260/13=20 A. VR=iR=20*5=100 V.

Discussion

27.	When is tanφ negative?(a) When inductive reactance is less than capacitive reactance(b) When inductive reactance is greater than capacitive reactance(c) When inductive reactance is equal to capacitive reactance(d) When inductive reactance is zeroI had been asked this question in an international level competition.I need to ask this question from Alternating Current in an RLC Circuit topic in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct option is (a) When inductive REACTANCE is LESS than capacitive reactance To explain I would say: tanφ is NEGATIVE when inductive reactance is less than capacitive reactance because CURRENT will LEAD the voltage.

Discussion

28.	Which type of ac waveform is given in figure?(a) sinusoidal(b) triangular(c) square(d) complex waveformI had been asked this question in homework.This interesting question is from Alternating Current in an RLC Circuit in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» The CORRECT answer is (a) sinusoidal For EXPLANATION: The figure depicts ac waveform of sinusoidal NATURE changing its polarity after regular intervals sinusoidally.

Discussion

29.	What is imaginary part of the impedance of RLC circuit?(a) Resistance(b) Conductance(c) Admittance(d) ReactanceThe question was posed to me in an interview.Question is from Current and Voltage in a Capacitive Circuit in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» RIGHT ANSWER is (d) Reactance Explanation: The COMBINATION of RESISTANCE and reactance is known as impedance.Z=R+jXwhere Z is impedance, R is resistance and X is reactance.X is imaginary part of Z.

Discussion

30.	What is not a frequency for ac current?(a) 50 Hz(b) 55 Hz(c) 0Hz(d) 60 HzThis question was addressed to me by my school principal while I was bunking the class.Origin of the question is Alternating Current in an RLC Circuit in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct answer is (C) 0Hz Easiest EXPLANATION: DC current is a type of CONSTANT current so it has frequency of zero hertz.So, AC current can have REST other FREQUENCIES other than zero.

Discussion

31.	In an RLC circuit, the power factor is always ____________(a) Positive(b) Negative(c) Depends on the circuit(d) ZeroI have been asked this question in an internship interview.Asked question is from Alternating Current in an RLC Circuit topic in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» Correct option is (c) Depends on the CIRCUIT The EXPLANATION: In an RLC series circuit, the power FACTOR depends on the number of RESISTORS and INDUCTORS in the circuit, hence it depends on the circuit.

Discussion

32.	What is sinϕ from impedance triangle?(a) XL/R(b) XL/Z(c) R/Z(d) Z/RThis question was addressed to me in examination.I need to ask this question from Resistance and Inductance in Series in chapter Single Phase Series Circuits of Basic Electrical Engineering
Answer» Correct ANSWER is (B) XL/Z The EXPLANATION: In Impedance triangle, Base is R, Hypotenuse is Z, HEIGHT is XL. So, sinϕ = XL/Z.

Discussion

33.	If in an alternating current circuit, resistance is 5 ohm, capacitive reactance is 12 ohm, what is the impedance?(a) 5 ohm(b) 10 ohm(c) 12 ohm(d) 13 ohmThe question was asked during an interview.I'm obligated to ask this question of Resistance and Capacitance in Series topic in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct OPTION is (d) 13 ohm The best EXPLANATION: R=5Ω, XC=12Ω Z^2=R^2+XC^2Substituting the VALUES we GET, Z^2 = 5^2 + 12^2 Z^2 = 169 Z=13 Ω.

Discussion

34.	Which, among the following, is the correct expression for φ.(a) φ=tan^-1 (XL/R)(b) φ=tan^-1 (R/XL)(c) φ=tan^-1 (XL*R)(d) φ=cos^-1 (XL/R)I had been asked this question in an online interview.This interesting question is from Resistance and Inductance in Series topic in chapter Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct option is (a) φ=tan^-1 (XL/R) The best I can EXPLAIN: From the IMPEDANCE TRIANGLE, we GET tanφ= XL/R. Hence φ=tan^-1 (XL/R).

Discussion

35.	What is the real part of the impedance of RLC circuit?(a) Resistance(b) Conductance(c) Admittance(d) ReactanceI have been asked this question in an interview for job.My doubt is from Current and Voltage in a Capacitive Circuit in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» RIGHT OPTION is (a) Resistance For EXPLANATION I WOULD say: The COMBINATION of resistance and reactance is known as impedance.Z=R+jXwhere Z is impedance, R is resistance and X is reactance.R is real part of Z.

Discussion

36.	A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a 100V 50Hz sinusoidal supply. Calculate the voltage across the inductor.(a) 52V(b) 82V(c) 65V(d) 76VThe question was posed to me in exam.I would like to ask this question from Resistance and Inductance in Series topic in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» Correct option is (B) 82V The best explanation: XL=2πFL = 10 OHM. Z^2=(R^2+XL^2) Therefore, the total impedance Z = 12.2ohm. V=IZ, therefore I=V/Z=100/12.2 = 8.2A.Voltage across INDUCTOR = 8.210 = 82V.

Discussion

37.	Choke involve use of _____________(a) Resistor(b) Capacitor(c) Inductor(d) TransistorI have been asked this question during an online interview.Question is from Mechanical Analogy, Current and Voltage in an Inductive Circuit in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» Correct option is (c) Inductor The best explanation: Choke is a type of COIL so it involves USE of inductor. CAPACITORS cannot be used in choke coil.

Discussion

38.	What is the current in an inductive circuit when the applied voltage is maximum?(a) Infinity(b) Maximum(c) Zero(d) Cannot be determinedI got this question in an interview for job.I'm obligated to ask this question of Mechanical Analogy, Current and Voltage in an Inductive Circuit in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» Right choice is (c) Zero Explanation: The CURRENT in an INDUCTIVE circuit is zero or minimum when the value of the APPLIED voltage is maximum.

Discussion

39.	The correct expression for the instantaneous current if instantaneous voltage is Vm(sint) in a resistive circuit is?(a) 1A(b) 2A(c) 3A(d) 4AThis question was posed to me by my school principal while I was bunking the class.Asked question is from Alternating Current in a Resistive & Inductive Circuit in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» Right OPTION is (b) 2A Easy explanation: We KNOW that:V=Vm(sint) Since i=V/R, we can WRITE, i=Vm(sint)/R.

Discussion

40.	In an inductive circuit, the current________ the voltage?(a) Leads(b) Lags(c) Is greater than(d) Is less thanI have been asked this question at a job interview.This is a very interesting question from Mechanical Analogy, Current and Voltage in an Inductive Circuit in chapter Single Phase Series Circuits of Basic Electrical Engineering
Answer» Right CHOICE is (b) LAGS The best explanation: In a PURE inductive circuit the voltage leads the current and the current lags the voltage by a PHASE difference of 90 degrees.

Discussion

41.	Can ohm’s law be applied in an ac circuit?(a) Yes(b) No(c) Depends on the rms current(d) Depends on the rms voltageThe question was posed to me in an online quiz.This intriguing question comes from Alternating Current in a Resistive & Inductive Circuit in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» Right choice is (a) Yes The best EXPLANATION: Ohm’s law can be applied in ac as well as dc CIRCUITS. It can be applied in ac circuits because the condition V=IR holds true EVEN in ac circuits.

Discussion

42.	A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a 100V 50Hz sinusoidal supply. Calculate the current in the circuit.(a) 2.2A(b) 4.2A(c) 6.2A(d) 8.2AI have been asked this question by my college professor while I was bunking the class.Enquiry is from Resistance and Inductance in Series topic in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» Right OPTION is (d) 8.2A Explanation: XL=2πf*L = 10 ohm. Z^2=(R^2+XL^2) THEREFORE the TOTAL impedance Z = 12.2ohm. V=IZ, therefore I=V/Z=100/12.2 = 8.2A.

Discussion

43.	Inductance is _____________________ to number of turns in the coil.(a) directly proportional(b) inversely proportional(c) equal(d) not relatedI have been asked this question during a job interview.Enquiry is from Mechanical Analogy, Current and Voltage in an Inductive Circuit topic in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» The CORRECT CHOICE is (a) DIRECTLY proportional Best EXPLANATION: L=µ0N^2A/l Inductance is directly proportional to number of TURNS in the coil.

Discussion

44.	What is the value of current in an inductive circuit when there is no applied voltage?(a) Minimum(b) Maximum(c) Zero(d) Cannot be determinedThis question was posed to me in my homework.The query is from Mechanical Analogy, Current and Voltage in an Inductive Circuit topic in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct choice is (b) Maximum The best I can explain: The current in an INDUCTIVE circuit is maximum when there is no voltage applied because the COILS of the inductor STORE electric flux.

Discussion

45.	In an inductive circuit, the voltage_______ the current?(a) Leads(b) Lags(c) Is greater than(d) Is less thanI have been asked this question at a job interview.This interesting question is from Mechanical Analogy, Current and Voltage in an Inductive Circuit topic in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» Correct choice is (a) Leads To explain I would SAY: In a pure inductive circuit the VOLTAGE leads the CURRENT and the current lags the voltage by a phase difference of 90 DEGREES.

Discussion

46.	Instantaneous voltage is the product of resistance and _____________ current in a resistive circuit.(a) Instantaneous(b) Average(c) RMS(d) PeakThis question was posed to me in unit test.This question is from Alternating Current in a Resistive & Inductive Circuit in division Single Phase Series Circuits of Basic Electrical Engineering
Answer» CORRECT choice is (a) INSTANTANEOUS To explain I would say: V=IR. So, V(t)=i(t)R Instantaneous voltage is the PRODUCT of resistance and instantaneous current in a RESISTIVE circuit.

Discussion

47.	A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a 100V 50Hz sinusoidal supply. Calculate the voltage across the resistor.(a) 31.8V(b) 57.4V(c) 67.3V(d) 78.2VI got this question in my homework.Question is from Resistance and Inductance in Series topic in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» The correct ANSWER is (b) 57.4V Easiest EXPLANATION: XL=2πfL = 10 ohm. Z^2=(R^2+XL^2) Therefore, the total impedance Z = 12.2ohm. V=IZ, therefore I=V/Z=100/12.2 = 8.2A.Voltage ACROSS resistor = 8.27 = 57.4V.

Discussion

48.	The correct expression for the instantaneous current in a resistive circuit is?(a) i=Vm(sint)/R(b) i=Vm(cost)/R(c) i=V(sint)/R(d) i=V(cost)/RThis question was posed to me in an interview for internship.My query is from Alternating Current in a Resistive & Inductive Circuit topic in section Single Phase Series Circuits of Basic Electrical Engineering
Answer» CORRECT choice is (a) i=Vm(sint)/R The BEST I can explain: The instantaneous voltage can be written in TERMS of the maximum voltage in the following manner: v=Vm(sint) SINCE i=v/R, we can write,i=Vm(sint)/R.

Discussion

49.	In which device inductor cannot be used?(a) filter circuit(b) transformer(c) choke(d) dielectricThis question was addressed to me at a job interview.My query is from Mechanical Analogy, Current and Voltage in an Inductive Circuit in chapter Single Phase Series Circuits of Basic Electrical Engineering
Answer» CORRECT answer is (d) dielectric To explain I would say: Inductor has wide number of applications. It is USED in LR filter CIRCUITS, transformer and choke coil.

Discussion

50.	A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a 100V 50Hz sinusoidal supply. Calculate the phase difference.(a) -55.1(b) 55.1(c) 66.1(d) -66.1I had been asked this question during an interview for a job.Question is taken from Resistance and Inductance in Series in portion Single Phase Series Circuits of Basic Electrical Engineering
Answer» RIGHT CHOICE is (a) -55.1 Explanation: φ=tan^-1(XL/R)=55.1 Since this is an INDUCTIVE circuit, the CURRENT will lag, hence φ= -55.1.

Discussion

Explore topic-wise InterviewSolutions in .

What is the relation between reactance, resistance and impedance?(a) Z=R+jX(b) Z=R+X(c) Z=R-X(d) Z=R-jXI got this question in an interview.My doubt stems from Current and Voltage in a Capacitive Circuit topic in division Single Phase Series Circuits of Basic Electrical Engineering

For an RL circuit, the phase angle is always ________(a) Positive(b) Negative(c) 0(d) 90The question was asked in a national level competition.My doubt stems from Resistance and Inductance in Series in chapter Single Phase Series Circuits of Basic Electrical Engineering

What is the resonance frequency of ac circuit?(a) 1/√LC(b) √(L/C)(c) √LC(d) LCI got this question by my college professor while I was bunking the class.Question is taken from Alternating Current in a Capacitive Circuit in portion Single Phase Series Circuits of Basic Electrical Engineering

What is the resonance condition?(a) When XL>XC(b) When XL

What is tanϕ for RC circuit?(a) XC/R(b) XL/R(c) R/Z(d) Z/RI have been asked this question during an online exam.Query is from Alternating Current in a Capacitive Circuit in division Single Phase Series Circuits of Basic Electrical Engineering

What is impedance at resonance?(a) maximum(b) minimum(c) zero(d) cannot be determinedI got this question by my school teacher while I was bunking the class.My query is from Alternating Current in a Capacitive Circuit in chapter Single Phase Series Circuits of Basic Electrical Engineering

What is the resistance offered by a capacitor?(a) Susceptance(b) Conductance(c) Admittance(d) ReactanceThis question was posed to me in exam.I'd like to ask this question from Current and Voltage in a Capacitive Circuit topic in division Single Phase Series Circuits of Basic Electrical Engineering

What is the value of impedance at resonance?(a) XL(b) XC(c) R(d) 0The question was posed to me during an online interview.The question is from Alternating Current in a Capacitive Circuit topic in division Single Phase Series Circuits of Basic Electrical Engineering

What is φ in terms of voltage?(a) φ=cos^-1V/VR(b) φ=cos^-1V*VR(c) φ=cos^-1VR/V(d) φ=tan^-1V/VRThe question was asked in quiz.The query is from Resistance and Inductance in Series in portion Single Phase Series Circuits of Basic Electrical Engineering

Which type of ac waveform is given in figure?(a) sinusoidal(b) triangular(c) square(d) complex waveformI had been asked this question in homework.This interesting question is from Alternating Current in an RLC Circuit in portion Single Phase Series Circuits of Basic Electrical Engineering

What is imaginary part of the impedance of RLC circuit?(a) Resistance(b) Conductance(c) Admittance(d) ReactanceThe question was posed to me in an interview.Question is from Current and Voltage in a Capacitive Circuit in division Single Phase Series Circuits of Basic Electrical Engineering

What is not a frequency for ac current?(a) 50 Hz(b) 55 Hz(c) 0Hz(d) 60 HzThis question was addressed to me by my school principal while I was bunking the class.Origin of the question is Alternating Current in an RLC Circuit in portion Single Phase Series Circuits of Basic Electrical Engineering

What is sinϕ from impedance triangle?(a) XL/R(b) XL/Z(c) R/Z(d) Z/RThis question was addressed to me in examination.I need to ask this question from Resistance and Inductance in Series in chapter Single Phase Series Circuits of Basic Electrical Engineering

What is the real part of the impedance of RLC circuit?(a) Resistance(b) Conductance(c) Admittance(d) ReactanceI have been asked this question in an interview for job.My doubt is from Current and Voltage in a Capacitive Circuit in section Single Phase Series Circuits of Basic Electrical Engineering

Choke involve use of _____________(a) Resistor(b) Capacitor(c) Inductor(d) TransistorI have been asked this question during an online interview.Question is from Mechanical Analogy, Current and Voltage in an Inductive Circuit in section Single Phase Series Circuits of Basic Electrical Engineering