105 + Interview Questions in Inductance In A Dc Circuit in Basic Electrical Engineering Page 2 InterviewSolution

51.	Among the following, which is the right formula for growth in an inductive circuit?(a) VL=V(1-e^-tR/L)(b) VL=(e^-tR/L)(c) VL=(1-e^-tR/L)(d) VL=V(e^-tR/L)I got this question in exam.This interesting question is from Growth in an Inductive Circuit topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» CORRECT answer is (d) VL=V(e^-tR/L) The BEST explanation: The correct formula for GROWTH in an inductive CIRCUIT is VL=V(e^-tR/L). As the TIME increases, voltage decreases.

Discussion

52.	Calculate the final flux in an inductor having inductance 4000 H, number of turns is 200 and the current changes from 5A to 7A. The initial flux is 760 Wb.(a) 200 Wb(b) 400 Wb(c) 600 Wb(d) 800 WbI got this question in examination.I need to ask this question from Ferromagnetic Cored Inductor in a DC Circuit in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Right option is (d) 800 WB Easiest explanation: From the formula of incremental inductance, we know that: L=(CHANGE in flux/Change in current)*Number of turns Substituting the values from the given QUESTION, we get a change in flux = 40 Wb. Change in flux = final flux- INITIAL flux. Thus final flux = 800 Wb.

Discussion

53.	Calculate the change in flux of an inductor having inductance 4000 H, number of turns is 200 and the current changes from 5A to 7A.(a) 20 Wb(b) 40 Wb(c) 60 Wb(d) 80 WbI had been asked this question in my homework.This interesting question is from Ferromagnetic Cored Inductor in a DC Circuit in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The CORRECT choice is (b) 40 Wb To explain: From the FORMULA of incremental inductance, we know that: L=(Change in flux/Change in current)*Number of turns Substituting the values from the given QUESTION, we get change in flux = 40 Wb.

Discussion

54.	Calculate the change in current in an inductor having inductance 4000H, number of turns is 200 and the flux changes from 760 to 800 Wb.(a) 2A(b) 4A(c) 6A(d) 8AThe question was posed to me in an interview.The question is from Ferromagnetic Cored Inductor in a DC Circuit in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Correct ANSWER is (a) 2A The best I can explain: From the formula of incremental INDUCTANCE, we KNOW that: L=(Change in flux/Change in CURRENT)*Number of turns Substituting the values from the given question, we get a change in current = 2A.

Discussion

55.	If either the inductance or the rate of change of current is doubled, the induced e.m.f?(a) Remains constant(b) Becomes zero(c) Doubles(d) Becomes halfThe question was posed to me by my college director while I was bunking the class.Enquiry is from Inductance in Terms of Flux Linkages Per Ampere in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» RIGHT answer is (c) Doubles To explain I would SAY: If either the INDUCTANCE or the RATE of change of CURRENT is doubled, the induced e.m.f. becomes double because of emf=LI/t.

Discussion

56.	Among the following, which is the right formula for inductance of N turns?(a) L=et/Ni(b) L=Ni e*t(c) L=Ni/et(d) L=N/ietThis question was posed to me in an interview for internship.My question is taken from Inductance in Terms of Flux Linkages Per Ampere in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» CORRECT OPTION is (a) L=et/Ni For explanation I WOULD say: We know that: emf=NLi/t Inductance = L = et/N.

Discussion

57.	In an inductive circuit, when the XL value increases, the circuit power factor?(a) Increases(b) Decreases(c) Remains the same(d) Becomes zeroI got this question during an online exam.My question is from Inductive and Non-Inductive Circuits topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The CORRECT choice is (b) Decreases Easy explanation: tan ϕ = XL/RandPower FACTOR=COS ϕ As XL increases, tan ϕ increases, ϕ increases, cos ϕ decreases and hence POWER factor decreases.

Discussion

58.	In case of Inductive circuit, Frequency is ______________ to the inductance.(a) Directly proportional(b) Inversely proportional(c) Unrelated(d) Much greater thanThe question was asked by my college director while I was bunking the class.I'm obligated to ask this question of Inductive and Non-Inductive Circuits topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Correct option is (b) INVERSELY proportional To explain: The FORMULA for frequency in an inductive CIRCUIT is: XL=2πf*L. Therefore: f is inversely proportional to L.

Discussion

59.	What is the SI unit of coupling coefficient?(a) H(b) H^-1(c) No unit(d) H^2The question was asked in an online interview.Origin of the question is Coupling Coefficient topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct CHOICE is (C) No UNIT Easiest explanation: The EXPRESSION to FIND mutual inductance is k=M/sqrt(L1L2)= H/sqrt(H*H)= 1. Therefore it does not have any unit.

Discussion

60.	Practical application of mutual inductance is ____________(a) DC generator(b) AC generator(c) Transformer(d) CapacitorI got this question during an internship interview.This key question is from Mutual Inductance in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Right CHOICE is (c) Transformer The explanation: A transformer is a DEVICE made of two or more INDUCTORS, one of which is powered by AC, inducing an AC VOLTAGE ACROSS the second inductor.

Discussion

61.	Calculate the value of emf in an inductor if the value of inductance is 15H and an average current of 5A flows through it in 10s.(a) 15V(b) 7.5V(c) 10V(d) 5.5VThe question was asked in an interview for job.Query is from Energy Stored in an Inductor topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Right choice is (B) 7.5V To EXPLAIN I would say: The EXPRESSION for EMF in an inductive CIRCUIT is: emf = LdI/dt Substituting the values from the given question, we get emf = 7.5V.

Discussion

62.	Calculate the current in an inductor if the energy stored is 160J and the inductance is 20H.(a) 1A(b) 2A(c) 3A(d) 4AI have been asked this question during a job interview.I need to ask this question from Energy Stored in an Inductor topic in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» CORRECT ANSWER is (d) 4A Best explanation: The EXPRESSION for energy in an INDUCTOR is: E = LI^2/2 Substituting the values from the given question, we get I=4A.

Discussion

63.	A coil has a resistance of 4 ohms and an inductance of 2H. It is connected to a 20V dc supply. Calculate the initial value of the voltage across the inductor.(a) 5V(b) 10V(c) 0 V(d) 20VThis question was posed to me during an online interview.My doubt is from Analysis of Growth & Decay topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct OPTION is (d) 20V Easy EXPLANATION: Initially, INDUCTOR behave as open circuit for dc CURRENT so, V = V0 = 20V i.e. same as voltage source.

Discussion

64.	Calculate the resistance in an inductive circuit whose time constant is 2s and the inductance is 10H.(a) 7ohm(b) 10ohm(c) 2ohm(d) 5ohmI have been asked this question at a job interview.Query is from Growth in an Inductive Circuit topic in section Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Correct option is (d) 5ohm To explain I WOULD say: We know that: TIME constant = L/R Substituting the VALUES from the given question, we get R=5ohm.

Discussion

65.	What is Helmholtz equation?(a) i=I(e^Rt/L)(b) i=I(1-e^-Rt/L)(c) i=I(1+e^-Rt/L)(d) i=I(e^-Rt/L)I got this question in class test.This intriguing question comes from Analysis of Growth & Decay topic in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct answer is (b) i=I(1-e^-Rt/L) For EXPLANATION: Helmholtz equation is an equation which gives the formula for the growth in an INDUCTIVE circuit. HENCE the Helmholtz formula is: i=I(1-e^-Rt/L).

Discussion

66.	A laminated steel ring is wound with 200 turns. When the magnetizing current varies between 5 and 7 A, the magnetic flux varies between 760 and 800 Wb. Calculate the inductance of the coil.(a) 40H(b) 4 H(c) 4000H(d) 0.004 HThe question was asked in a job interview.I'd like to ask this question from Ferromagnetic Cored Inductor in a DC Circuit in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» CORRECT answer is (c) 4000H Easy explanation: From the formula of INCREMENTAL INDUCTANCE, we know that: L=(Change in flux/Change in CURRENT)*Number of turns Substituting the values from the given question, we get L = 4000 H.

Discussion

67.	What happens to the effective inductance when a ferromagnetic core is introduced?(a) Increases(b) Decreases(c) Remains the same(d) Becomes zeroThe question was posed to me during a job interview.This intriguing question comes from Ferromagnetic Cored Inductor in a DC Circuit in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» RIGHT option is (a) Increases Easiest explanation: The EFFECTIVE INDUCTANCE increases when a FERROMAGNETIC CORE is introduced within an inductor because of the flux increases. Inductance varies directly with the flux hence it increases.

Discussion

68.	Among the following, which is the right formula for decay in an inductive circuit?(a) i=I(1-e^-t/time constant)(b) i=I(1-e^t /time constant)(c) i=(1-e^-t /time constant)(d) i=I(e^-t /time constant)This question was posed to me in unit test.My question is taken from Analysis of Growth & Decay topic in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Correct option is (d) i=I(e^-t /time CONSTANT) Explanation: The correct formula for decay in an inductive circuit is i=I(e-t /time constant). As the time increases, the CURRENT in the INDUCTOR decreases, the VOLTAGE also increases.

Discussion

69.	What happens to the coupling coefficient when the flux linkage of coil 1 and coil 2 increases?(a) Increases(b) Decreases(c) Remains the same(d) Becomes zeroI had been asked this question in exam.My question is based upon Coupling Coefficient topic in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Correct choice is (a) Increases Explanation: When the flux LINKAGE of COIL 1 and coil 2 increases, its MUTUAL inductance increases. The coupling coefficient is directly PROPORTIONAL to the mutual inductance hence as mutual inductance increases, the coupling coefficient increases.

Discussion

70.	What is the coupling coefficient when all the flux of coil 1 links with coil 2?(a) 0(b) 100(c) 1(d) Insufficient information providedThis question was posed to me in final exam.I'm obligated to ask this question of Coupling Coefficient topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» CORRECT option is (c) 1 Easy explanation: When all the flux of coil 1 LINKS with coil 2 it is KNOWN as an ideal coupling where the coupling coefficient is 1.

Discussion

71.	What is the SI unit of mutual inductance?(a) Ohm(b) Henry(c) Volt(d) SiemensThis question was posed to me during an interview for a job.The doubt is from Mutual Inductance topic in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» RIGHT option is (b) HENRY For EXPLANATION: Mutual inductance is the inductance between the two neighbouring coils. Since it is a TYPE of inductance, its UNIT is that of inductance, that is, henry.

Discussion

72.	What is the SI unit of mutual inductance?(a) Ohm(b) Henry(c) Volt(d) SiemensThis question was addressed to me in an interview for job.My question comes from Mutual Inductance topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer»

Discussion

73.	Calculate the initial current in an inductor having inductance 4000 H, number of turns is 200 and the flux changes from 760 to 800 Wb. Current changes to 7A.(a) 10A(b) 2A(c) 3A(d) 5AThe question was asked in a job interview.My enquiry is from Ferromagnetic Cored Inductor in a DC Circuit in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Correct answer is (d) 5A For explanation: From the formula of incremental inductance, we know that: L=(CHANGE in flux/Change in current)*Number of turns Substituting the VALUES from the GIVEN question, we GET change in current = 2A. Change in current = final current- initial current. 2=7-initial current. Initial current = 5A.

Discussion

74.	What happens to the inductance when the magnetic field strength decreases?(a) Increases(b) Decreases(c) Remains the same(d) Becomes zeroThis question was addressed to me during an interview.My question is taken from Factors Determining the Inductance of a Coil in section Inductance in a DC Circuit of Basic Electrical Engineering
Answer» RIGHT option is (b) DECREASES For explanation: Inductance is DIRECTLY proportional to the MAGNETIC field strength in the coil, HENCE as the magnetic field strength decreases, inductance decreases.

Discussion

75.	If tan ϕ = 10 and the resistance is 2 ohm, calculate the inductive reactance.(a) 10 ohm(b) 20 ohm(c) 30 ohm(d) 40 ohmI got this question by my college professor while I was bunking the class.My question comes from Inductive and Non-Inductive Circuits in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct choice is (b) 20 ohm The EXPLANATION is: We KNOW that: tan(ϕ)=XL/R From the given QUESTION, we FIND that the inductive reactance is 20 ohm.

Discussion

76.	What is the coupling coefficient when there is ideal coupling?(a) 0(b) 100(c) 1(d) Insufficient information providedI have been asked this question by my college professor while I was bunking the class.I'm obligated to ask this question of Coupling Coefficient in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct OPTION is (c) 1 To ELABORATE: When all the flux of coil 1 links with coil 2 it is known as an ideal COUPLING where the coupling coefficient is 1.

Discussion

77.	Which, among the following, is the correct expression for mutual inductance?(a) M=N2φ2/I2(b) M=N2φ2/I1(c) M=N1φ2/I2(d) M=N1φ1/I1I had been asked this question in exam.Question is from Mutual Inductance topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Right choice is (b) M=N2φ2/I1 For explanation I would SAY: Mutual INDUCTANCE is the product of the number of turns in one coil and the flux LINKAGES of that coil, divided by the current in the other coil. HENCE M=N2φ2/I1 is the correct expression.

Discussion

78.	If the current in one coil becomes steady, the current in neighbouring coilis?(a) Zero(b) Infinity(c) Doubles(d) HalvesI got this question by my school principal while I was bunking the class.This interesting question is from Mutual Inductance in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Right option is (a) Zero The BEST I can explain: A current is induced when there is changing magnetic FLUX. HENCE the induced current in NEIGHBOURING COIL is zero when the current is steady.

Discussion

79.	The phenomenon due to which there is an induced current in one coil due to the current in a neighbouring coil is?(a) Electromagnetism(b) Susceptance(c) Mutual inductance(d) Steady currentI had been asked this question in an interview for internship.Origin of the question is Mutual Inductance in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Correct answer is (c) Mutual inductance The best I can explain: When there is a CURRENT in a coil, DUE to the magnetic field CAUSED by the current there is current induced in the neighbouring coil as well. This is known as mutual inductance.

Discussion

80.	What is the expression for current in the given circuit?(a) i=2(e^-2t)A(b) i=2(1-e^-2t)A(c) i=2(e^2t)A(d) i=2(1+e^-2t)AI got this question during an interview for a job.My query is from Transients in LR Networks topic in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» CORRECT answer is (b) i=2(1-e^-2t)A The explanation is: APPLYING KVL in above circuit, we get 60-30i-15di/dt =0 i=2(1-e^-2t)A

Discussion

81.	Calculate the number of turns in an inductor with a ferromagnetic core when the inductance is 4000 H, the current changes from 5A to 7A and the flux changes from 760 to 800 Wb.(a) 100(b) 200(c) 300(d) 400I have been asked this question by my college professor while I was bunking the class.This is a very interesting question from Ferromagnetic Cored Inductor in a DC Circuit topic in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Right CHOICE is (b) 200 Best explanation: From the formula of incremental inductance, we know that: L=(Change in flux/Change in CURRENT)*NUMBER of turns Substituting the values from the given question, we get N=200.

Discussion

82.	What is the unit for inductive reactance?(a) Henry(b) Ohm(c) Farad(d) VoltsThis question was posed to me during an online exam.Asked question is from Inductive and Non-Inductive Circuits topic in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct choice is (b) Ohm To elaborate: INDUCTIVE REACTANCE is nothing but the impedance. Impedance is the AC equivalent of resistance, HENCE the unit for inductive reactance is ohm.

Discussion

83.	If the resistance in a circuit is 2 ohm and the impedance is 20 ohm, calculate the power factor.(a) 1/10(b) 1/20(c) 1/30(d) 1/40The question was asked by my college director while I was bunking the class.Question is taken from Inductive and Non-Inductive Circuits in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» RIGHT OPTION is (a) 1/10 To EXPLAIN: We know that: cos(ϕ)=R/Z = 2/20 = 1/10 ohm.

Discussion

84.	What is the power in the magnetic field if the current in a coil has a constant inductance of L henrys grows at a uniform rate?(a) LI/2t(b) LI^2/2t(c) L/2It(d) L/2I^2tThis question was posed to me at a job interview.Question is taken from Energy Stored in an Inductor topic in section Inductance in a DC Circuit of Basic Electrical Engineering
Answer» RIGHT option is (B) LI^2/2t For EXPLANATION I WOULD SAY: EMF induced in the coil is Ldi/dt. Energy=eidt=Lidi/dtdt=Li^2/2. Power=Energy/Time = Li^2/2t.

Discussion

85.	Find voltage across 10H inductor.(a) 2V(b) 10V(c) 12V(d) 20VThis question was posed to me by my school principal while I was bunking the class.Origin of the question is Coils Connected in Series in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct choice is (B) 10V The EXPLANATION is: e=Ldi/dt Leq=2+10+12+20=44H di/dt=44/44 = 1 A/s. Voltage ACROSS 10H inductor = 10di/dt = 101=10V.

Discussion

86.	The flux linkage in coil 1 is x and it has 500 turns and the current in coil 2 is 2A, calculate the value of x if the mutual inductance is 750H.(a) 1Wb(b) 2Wb(c) 3Wb(d) 4WbThe question was posed to me in semester exam.My question is from Mutual Inductance in section Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Correct CHOICE is (c) 3WB Explanation: We KNOW that mutual inductance is the product of the NUMBER of turns in one coil and the flux linkages of that coil, divided by the CURRENT in the other coil. φ=750*2/500 = 3Wb.

Discussion

87.	What is the equivalent inductance when inductors are connected in series?(a) Sum of all the individual inductances(b) Product of all the individual inductances(c) Sum of the reciprocal of all the individual inductances(d) Product of the reciprocal of all the individual inductancesI had been asked this question in a job interview.The query is from Coils Connected in Series in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct OPTION is (a) Sum of all the INDIVIDUAL INDUCTANCES Explanation: When inductances are CONNECTED in series, the EQUIVALENT inductance is equal to the sum of all the individual inductance values.

Discussion

88.	An RL network is one which consists of ____________(a) Resistor and capacitor in parallel(b) Resistor and capacitor in series(c) Resistor and inductor in parallel(d) Resistor and inductor in seriesThe question was asked by my school teacher while I was bunking the class.The question is from Transients in LR Networks in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct answer is (d) Resistor and inductor in series For EXPLANATION I would SAY: An R-L NETWORK is a network which consists of a resistor which is connected in series to an inductor.

Discussion

89.	Calculate the emf induced in an inductor if the inductance is 10H and the current is 2A in 4s.(a) 2.5V(b) 1.5V(c) 3.5V(d) 5VThe question was posed to me in an interview for internship.My query is from Energy Stored in an Inductor topic in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct choice is (d) 5V For explanation: The EXPRESSION for emf in an inductive circuit is: emf = LdI/dt Substituting the values from the GIVEN question, we GET emf = 5V.

Discussion

90.	In a pure inductive circuit, the power factor is?(a) Maximum(b) Minimum(c) 0(d) InfinityI got this question during an online exam.This question is from Growth in an Inductive Circuit in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct choice is (C) 0 For explanation I would say: In a PURE inductive circuit, the current is lagging by 90 degrees from the voltage. The POWER FACTOR is the cosine of the angle between the voltage and the current. If the angle between the voltage and the current is 90, then cos90=0. Hence, the power factor is zero.

Discussion

91.	As the number of turns in the coil increases, what happens to the inductance of the coil?(a) Increases(b) Decreases(c) Remains the same(d) Becomes zeroThis question was addressed to me during an internship interview.I need to ask this question from Factors Determining the Inductance of a Coil topic in section Inductance in a DC Circuit of Basic Electrical Engineering
Answer» RIGHT choice is (a) Increases The BEST explanation: Inductance is directly proportional to the SQUARE of the NUMBER of turns in the coil, HENCE as the number of turns increases, inductance also increases.

Discussion

92.	Find voltage across 2H inductor.(a) 2V(b) 10V(c) 12V(d) 20VThis question was addressed to me in an interview for internship.This question is from Coils Connected in Series topic in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The CORRECT answer is (a) 2V The EXPLANATION is: e=Ldi/dt Leq=2+10+12+20=44H di/dt=44/44 = 1 A/s. Voltage across 2H inductor = 2di/dt = 21=2V.

Discussion

93.	The charging time constant of a circuit consisting of an inductor is the time taken for the current in the inductor to become __________% of the initial current.(a) 33(b) 63(c) 37(d) 36This question was posed to me in an interview.This intriguing question comes from Growth in an Inductive Circuit in division Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Correct OPTION is (B) 63 Easiest explanation: We know that: i=i0(1-e^-tR/L). When t=L/R, we have: i=i0(1-e^-1) = 0.63*i0. Hence the TIME CONSTANT is the time taken for the current in an inductive circuit to BECOME 0.63 times its initial current.

Discussion

94.	Calculate the time constant of an inductive circuit having resistance 5 ohm and inductance 10H.(a) 2s(b) 4s(c) 5s(d) 10sI have been asked this question during a job interview.This intriguing question originated from Growth in an Inductive Circuit in portion Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct option is (a) 2s For explanation I would say: We KNOW that: TIME CONSTANT = L/R Substituting the VALUES from the given QUESTION, we get a time constant = 2s.

Discussion

95.	When a ferromagnetic core is inserted into an inductor, what happens to the flux linkage?(a) Increases(b) Decreases(c) Remains the same(d) Becomes zeroThe question was posed to me during an internship interview.My enquiry is from Ferromagnetic Cored Inductor in a DC Circuit in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct answer is (a) Increases Easiest explanation: When a ferromagnetic core is introduced into an INDUCTOR, its flux increases because the number of MAGNETIC FIELD lines increases due to the introduction of magnetic field within the COIL.

Discussion

96.	What happens to the inductance as the area of the cross section of the coil increases?(a) Increases(b) Decreases(c) Remains the same(d) Becomes zeroThe question was posed to me during an interview.The question is from Factors Determining the Inductance of a Coil in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» RIGHT CHOICE is (a) Increases To explain I WOULD say: L=µ0N^2A/l, HENCE as the area of cross section A increases, the inductance also increases.

Discussion

97.	Find voltage across 20H inductor.(a) 2V(b) 10V(c) 12V(d) 20VThis question was addressed to me by my school teacher while I was bunking the class.My question is from Coils Connected in Series topic in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The CORRECT ANSWER is (d) 20V Easiest EXPLANATION: e=Ldi/dt Leq=2+10+12+20=44H di/dt=44/44 = 1 A/s. Voltage across 20H INDUCTOR = 20di/dt = 201=20V.

Discussion

98.	When inductors are connected in series, the voltage across each inductor is _________(a) Equal(b) Different(c) Zero(d) InfinityThis question was posed to me in exam.Question is from Coils Connected in Series in section Inductance in a DC Circuit of Basic Electrical Engineering
Answer» The correct option is (b) DIFFERENT For EXPLANATION: In a SERIES circuit, the CURRENT across all elements remain the same and the total voltage of the circuit is the sum of the VOLTAGES across all the elements. The voltage across each inductor in series is different.

Discussion

99.	Calculate the equivalent inductance between A and B.(a) 30H(b) 54H(c) 44H(d) 60HI have been asked this question in an interview for job.This question is from Coils Connected in Series in chapter Inductance in a DC Circuit of Basic Electrical Engineering
Answer» RIGHT CHOICE is (C) 44H Best EXPLANATION: The 4 inductors are connected in series, hence their equivalent inductance is: Leq=L1+L2+L3+L4=44H.

Discussion

100.	The discharging time constant of a circuit consisting of an inductor is the time taken for the voltage in the inductor to become __________ % of the initial voltage.(a) 33(b) 63(c) 37(d) 36The question was posed to me during an online exam.I'm obligated to ask this question of Analysis of Growth & Decay topic in section Inductance in a DC Circuit of Basic Electrical Engineering
Answer» Right choice is (c) 37 For EXPLANATION: We know that: V=V0(e^-tR/L). When t=L/R, we have: V=V0(e^-1) = 0.37*Vsub>0. Hence the time constant is the time TAKEN for the voltage in an inductive circuit to become 0.37 times its INITIAL voltage.

Discussion

Explore topic-wise InterviewSolutions in .

What is the SI unit of coupling coefficient?(a) H(b) H^-1(c) No unit(d) H^2The question was asked in an online interview.Origin of the question is Coupling Coefficient topic in portion Inductance in a DC Circuit of Basic Electrical Engineering

Practical application of mutual inductance is ____________(a) DC generator(b) AC generator(c) Transformer(d) CapacitorI got this question during an internship interview.This key question is from Mutual Inductance in division Inductance in a DC Circuit of Basic Electrical Engineering

What is Helmholtz equation?(a) i=I(e^Rt/L)(b) i=I(1-e^-Rt/L)(c) i=I(1+e^-Rt/L)(d) i=I(e^-Rt/L)I got this question in class test.This intriguing question comes from Analysis of Growth & Decay topic in chapter Inductance in a DC Circuit of Basic Electrical Engineering

What is the SI unit of mutual inductance?(a) Ohm(b) Henry(c) Volt(d) SiemensThis question was posed to me during an interview for a job.The doubt is from Mutual Inductance topic in chapter Inductance in a DC Circuit of Basic Electrical Engineering

What is the SI unit of mutual inductance?(a) Ohm(b) Henry(c) Volt(d) SiemensThis question was addressed to me in an interview for job.My question comes from Mutual Inductance topic in portion Inductance in a DC Circuit of Basic Electrical Engineering

Which, among the following, is the correct expression for mutual inductance?(a) M=N2φ2/I2(b) M=N2φ2/I1(c) M=N1φ2/I2(d) M=N1φ1/I1I had been asked this question in exam.Question is from Mutual Inductance topic in portion Inductance in a DC Circuit of Basic Electrical Engineering

What is the expression for current in the given circuit?(a) i=2(e^-2t)A(b) i=2(1-e^-2t)A(c) i=2(e^2t)A(d) i=2(1+e^-2t)AI got this question during an interview for a job.My query is from Transients in LR Networks topic in division Inductance in a DC Circuit of Basic Electrical Engineering

What is the unit for inductive reactance?(a) Henry(b) Ohm(c) Farad(d) VoltsThis question was posed to me during an online exam.Asked question is from Inductive and Non-Inductive Circuits topic in portion Inductance in a DC Circuit of Basic Electrical Engineering

Find voltage across 10H inductor.(a) 2V(b) 10V(c) 12V(d) 20VThis question was posed to me by my school principal while I was bunking the class.Origin of the question is Coils Connected in Series in portion Inductance in a DC Circuit of Basic Electrical Engineering

In a pure inductive circuit, the power factor is?(a) Maximum(b) Minimum(c) 0(d) InfinityI got this question during an online exam.This question is from Growth in an Inductive Circuit in division Inductance in a DC Circuit of Basic Electrical Engineering

Find voltage across 2H inductor.(a) 2V(b) 10V(c) 12V(d) 20VThis question was addressed to me in an interview for internship.This question is from Coils Connected in Series topic in chapter Inductance in a DC Circuit of Basic Electrical Engineering

Find voltage across 20H inductor.(a) 2V(b) 10V(c) 12V(d) 20VThis question was addressed to me by my school teacher while I was bunking the class.My question is from Coils Connected in Series topic in chapter Inductance in a DC Circuit of Basic Electrical Engineering

When inductors are connected in series, the voltage across each inductor is _________(a) Equal(b) Different(c) Zero(d) InfinityThis question was posed to me in exam.Question is from Coils Connected in Series in section Inductance in a DC Circuit of Basic Electrical Engineering

Calculate the equivalent inductance between A and B.(a) 30H(b) 54H(c) 44H(d) 60HI have been asked this question in an interview for job.This question is from Coils Connected in Series in chapter Inductance in a DC Circuit of Basic Electrical Engineering