Alternating Current and Voltage Question & AnswersSeptember 13, 2021 By Wat Electrical Leave a Comment This article lists 100 Alternating Current and Voltage MCQs for engineering students. All the Alternating Current and Voltage Questions & Answers given below includes solution and link wherever possible to the relevant topic.In the 1880s the DC was discovered by Thomas Edison and the AC was discovered by Nikola Tesla. The electricity we use in our homes and offices is generated in power stations. The electricity produced in power stations is delivered by transmission lines over a long distance, and the amount of power generated is given by a product of current and voltage. In India, the electricity standards are 230 volts and 50 hertz. 1). The power factor of an AC voltage lies between ______________0 and 11 and 22 and 33 and 4HintThe power factor of an AC voltage lies between zero and one 2). The alternating current voltage have _______________PhaseNeutralBoth a and bNone of the aboveHintThe alternating current voltage has both phase and neutral 3). Which one of the following requires for transmission?AC voltageDC voltageBoth a and bNone of the aboveHintAn AC voltage is required for transmission 4). Which one of the following doesn’t have amplitude?AC voltageDC voltageBoth a and bNone of the aboveHintThe DC voltage doesn’t have an amplitude 5). The passive parameter in an AC voltage is _________ImpedanceResistanceBoth a and bNone of the aboveHintThe passive parameter in an AC voltage is impedance 6). The ratio of real power divided by apparent power is known as _____________Apparent powerPower factorReactive factorNone of the aboveHintThe ratio of real power divided by apparent power is known as the power factor 7). The expression for capacitive reactance is given by _____________1/ꙍCꙍLWCNone of the aboveHintThe expression for capacitive reactance is given by 1/ꙍC 8). The ratio f reactive power divided by apparent power is known as __________Apparent powerPower factorReactive factorNone of the aboveHintThe ratio f reactive power divided by apparent power is known as reactive power 9). Which one of the following voltages is obtained from a generator?AC voltageDC voltageBoth a and bNone of the aboveHintAn AC voltage is obtained from a generator 10). Which one of the following voltages is unidirectional?AC voltageDC voltageBoth a and bNone of the aboveHintThe direction of an AC voltage is unidirectional 11). Which one of the following currents is discovered by Thomas Edison?ACDCBoth a and bNone of the aboveHintThe direct current is discovered by Thomas Edison 12). Which one of the following currents is discovered by Nikola Tesla?ACDCBoth a and bNone of the aboveHintAn alternating current is discovered by Nikola Tesla 13). The expression for inductive reactance is given by _____________1/ꙍCꙍLWCNone of the aboveHintThe expression for inductive reactance is given by ꙍL 14). The expression for power loss is equal to ___________IRI^2 * R2R1/RHintThe expression for power loss is equal to I^2 * R 15). In India the electricity standards are _____________10 volts and 50 hertz30 volts and 50 hertz20 volts and 50 hertz230 volts and 50 hertzHintIn India, the electricity standards are 230 volts and 50 hertz 16). In US the electricity standards are _____________10 volts and 50 hertz30 volts and 50 hertz120 volts and 60 hertz230 volts and 50 hertzHintIn the US the electricity standards are 120 volts and 60 hertz 17). How many cycles does AC produce per second?10 cycles20 cycles30 cycles50 cyclesHintAn alternating current produces 50 cycles per second 18). The period of a wave is related to ___________ quantityRateTimeFrequencyNone of the aboveHintThe period of a wave is related to time quantity 19). The frequency of a wave is related to ___________ quantityRateTimeFrequencyNone of the aboveHintThe frequency of a wave is related to rate quantity 20). Which one of the following is expressed in seconds per cycle?RateTimePeriodNone of the aboveHintThe period is expressed in seconds per cycle 21). Which one of the following is expressed in cycles per second?FrequencyTimePeriodNone of the aboveHintThe frequency is expressed in cycles per second 22). The expression for voltage amplitude is given by _____________1/ꙍCIꙍLWCNone of the aboveHintThe expression for voltage amplitude is given by IꙍL 23). The frequency is _________ if the period is longerHigherLowerConstantModerateHintThe frequency is lower if the period is longer 24). The period is _________ if the frequency is higherHigherLowerConstantModerateHintThe period is lower if the frequency is higher 25). What is the unit to measure bandwidth?OhmsBits/secHzNone of the aboveHintThe unit to measure bandwidth is bits/secAlternating Current and Voltage Important MCQs 26). The induced EMF is categorized into ________________OneTwoThreeFourHintThe induced EMF is categorized into two types they are dynamically induced and statically induced EMF 27). The statically induced EMF is categorized into _______________OneTwoThreeFourHintThe statically induced EMF is categorized into two types they are self-induced and mutually induced EMF 28). In _______________ phase the power supplies through one conductorSingleTwoThreeNone of the aboveHintIn single-phase, the power supplies through one conductor 29). The number of wires required for completing the single-phase circuit is ____________OneTwoThreeFourHintThe number of wires required for completing the single-phase circuit is two 30). The single-phase alternating current circuit carries ____________100 volts110 volts200 volts230 voltsHintThe single-phase alternating current circuit carries 230 volts 31). In which one of the following phases the efficiency is high?SingleDoubleThreeNone of the aboveHintIn three-phase, the efficiency is high compare to single phase 32). In _______________ phase the power supplies through three conductorsSingleTwoThreeNone of the aboveHintIn three-phase the power supplies through three conductors 33). Which one of the following phases is more economical?SingleDoubleThreeNone of the aboveHintIn three-phase is more economical compare to single phase 34). The loss is maximum in __________ phaseSingleDoubleThreeNone of the aboveHintThe loss is maximum in a single phase 35). The phase impedances in balanced load are equal in __________PhaseMagnitudeBoth a and bNone of the aboveHintThe phase impedances in balanced load are equal in both phase and magnitude 36). The transmission efficiency is high in __________ phase systemSingleDoubleThreeNone of the aboveHintThe transmission efficiency is high in a three-phase system 37). The cross-sectional area of conductors are large in _________ phase systemSingleDoubleThreeNone of the aboveHintThe cross-sectional area of conductors are large in a single-phase system Read more about Electrical Conductors 38). In which one of the following voltage the polarity is fixed?AC voltageDC voltageBoth a and bNone of the aboveHintIn DC voltage the polarity is fixed whereas in AC voltage the polarity is not fixed 39). The number of wires required for completing the three-phase circuit is ____________OneTwoThreeFourHintThe number of wires required for completing the three-phase circuit is four 40). Which one of the following is easier to measure?AC voltageDC voltageBoth a and bNone of the aboveHintThe DC voltage is easier to measure 41). Which one of the following is easier to amplify?AC voltageDC voltageBoth a and bNone of the aboveHintAn AC voltage is easier to amplify 42). The RMS value of the sine waveform is __________1.4140.70711.11None of the aboveHintThe RMS value of the sine waveform is 0.7071 43). The crest factor value of sine waveform is ____________1.4140.70711.11None of the aboveHintThe crest factor value of sine waveform is 1.414 44). The three-phase alternating current circuit carries ____________100 volts110 volts200 volts415 voltsHintThe three-phase alternating current circuit carries 415 volts 45). The form factor value of sine waveform is ____________1.4140.70711.11None of the aboveHintThe form factor value of sine waveform is 1.11 46). The ratio of RMS value divided by average value is known as ____________ factorPeakFormCrestNone of the aboveHintThe ratio of RMS value divided by average value is known as form factor 47). The ripple factor is defined as a ratio of _______________Peak voltage/DC voltagePeak voltage/AC voltage(RMS voltage/DC voltage)*100None of the aboveHintThe ripple factor is defined as a ratio of (RMS voltage/DC voltage)*100 48). Which one of the following phase networks is complicated?SingleDoubleThreeNone of the aboveHintIn three-phase network is complicated compare to single phase 49). The RMS value of the triangular waveform is __________1.4140.70710.577None of the aboveHintThe RMS value of the triangular waveform is 0.577 50). The crest factor value of the triangular waveform is ____________1.4140.70711.732None of the aboveHintThe crest factor value of the triangular waveform is 1.732Alternating Current and Voltage MCQs for Quiz 51). The form factor value of the triangular waveform is ____________1.4140.70711.154None of the aboveHintThe form factor value of the triangular waveform is 1.154 52). The mean value of the sine wave is ____________0.6370.3180.51HintThe mean value of the sine wave is 0.637 53). The peak to average power ratio of sine wave is _______________3.01 dB6.02 dB4.77 dBNone of the aboveHintThe peak to average power ratio of the sine wave is 3.01 dB 54). The ratio of peak value divided by RMS value is known as ____________ factorPeakFormCrestNone of the aboveHintThe ratio of peak value divided by RMS value is known as crest factor 55). The power factor of the series resonance circuit is ________________ZeroInfinityOneUnityHintThe power factor of the series resonance circuit is unity 56). The RMS value of the square waveform is __________1.4140.70710.5771HintThe RMS value of the square waveform is one 57). The crest factor value of the square waveform is ____________1.4140.70711None of the aboveHintThe crest factor value of the square waveform is one 58). The form factor value of the square waveform is ____________1.4140.70711.154OneHintThe form factor value of the square waveform is one 59). The mean value of the half-wave rectified sine is ____________0.6370.3180.51HintThe mean value of the half-wave rectified sine is 0.318 60). Which one of the following circuits magnifies voltage?Series resonanceParallel resonanceBoth a and bNone of the aboveHintThe series resonance circuit magnifies voltage 61). Which one of the following circuits is also known as the acceptor circuit?Series resonanceParallel resonanceBoth a and bNone of the aboveHintThe series resonance circuit is also known as the acceptor circuit 62). The power factor at resonance is unity in ______________ circuitSeries RLCParallel RLCBoth a and bNone of the aboveHintThe power factor at resonance is unity in both series and parallel circuit 63). The ratio of inductor voltage or capacitor voltage by supply voltage is known as ___________ factorQualityCrestPeakNone of the aboveHintThe ratio of inductor voltage or capacitor voltage by supply voltage is known as the quality factor 64). The RMS value of saw-tooth waveform is __________1.4140.70710.5771HintThe RMS value of the saw-tooth waveform is 0.577 65). The crest factor value of saw-tooth waveform is ____________1.7320.70711None of the aboveHintThe crest factor value of the saw-tooth waveform is 1.732 66). The form factor value of saw-tooth waveform is ____________1.4140.70711.154oneHintThe form factor value of the saw-tooth waveform is 1.154 67). The mean value of full-wave rectified sine is ____________0.6370.3180.51HintThe mean value of full-wave rectified sine is 0.637 68). The peak to average power ratio of full-wave rectified sine is ____________3.01 dB6.02 dB4.77 dBNone of the aboveHintThe peak to average power ratio of full-wave rectified sine is 3.01 dB 69). Which one of the following circuits magnifies current?Series resonanceParallel resonanceBoth a and bNone of the aboveHintThe parallel resonance circuit magnifies current 70). Which one of the following circuits is also known as the rejector circuit?Series resonanceParallel resonanceBoth a and bNone of the aboveHintThe parallel resonance circuit is also known as the rejector circuit 71). The ratio of bandwidth divided by resonant frequency is known as _____________Quality factorCrest factorSelectivityNone of the aboveHintThe ratio of bandwidth divided by resonant frequency is known as selectivity 72). What is the unit of self-inductance?OhmHenryAmpereNone of the aboveHintThe unit of self-inductance is henry 73). How many types of inductance are there?OneTwoThreeFourHintThe inductances are of two types they are mutual and self-inductance 74). The mean value of triangular wave is ____________0.6370.3180.51HintThe mean value of triangular wave is 0.5 75). The peak to average power ratio of half-wave rectified sine is ____________3.01 dB6.02 dB4.77 dBNone of the aboveHintThe peak to average power ratio of half-wave rectified sine is 6.02 dBAlternating Current and Voltage MCQs for Students Read more about Rectifier 76). Which one of the following is a correct expression for resonant angular frequency?1/√LC1/LC1/√RCNone of the aboveHintThe resonant angular frequency is equal to 1/√LC 77). Which one of the following is a capacitive reactance equation?1/ꙍC1/LC1/RCNone of the aboveHintThe expression for capacitive reactance is 1/ꙍC 78). Which one of the following is an inductive reactance equation?1/ꙍC1/ꙍL1/RCNone of the aboveHintThe expression for inductive reactance is 1/ꙍL 79). The root mean square of the current is known as ______________RMS currentRMS voltageResonant frequencyNone of the aboveHintThe root mean square of the current is known as RMS current 80). How many ways are there to measure the alternating current and voltage?OneTwoThreeFourHintThere are three ways are there to measure the alternating current and voltage they are peak value, average or mean value, and RMS value 81). Which one of the following is a current expression for angular velocity?ꙍ=2πfꙍ=2fꙍ=8πfNone of the aboveHintThe current expression for angular velocity is ꙍ=2πf 82). Which one of the following is also known as the amplitude factor?Resonance factorCrest factorForm factorNone of the aboveHintThe crest factor is also known as the amplitude factor 83). The peak to average power ratio of the triangular wave is ____________3.01 dB6.02 dB4.77 dBNone of the aboveHintThe peak to average power ratio of the triangular wave is 4.77dB 84). The root mean square of the voltage is known as ______________RMS currentRMS voltageResonant frequencyNone of the aboveHintThe root mean square of the current is known as the RMS voltage 85). What are the advantages of an alternating current?Cheaper than DCCan be stepped down or stepped up by transformerCan be converted into DC by rectifierAll of the aboveHintThe advantages of an alternating current are cheaper than DC, can be stepped down or stepped up by transformer, and can be converted into DC by rectifier 86). The magnetic field is stationary in ____________ motorACDCBoth a and bNone of the aboveHintThe magnetic field is stationary in direct current motor 87). The armature is stationary in ______________ motorACDCBoth a and bNone of the aboveHintThe armature is stationary in alternating current motor 88). Which one of the following generators doesn’t have a commutator?AC generatorsDC generatorsBoth a and bNone of the aboveHintThe AC generators don’t have a commutator 89). Which one of the following motors doesn’t use brushes?AC motorsDC motorsBoth a and bNone of the aboveHintThe alternating current motors don’t use brushes 90). What are the advantages of an AC motor?High power factorLow-costReliableAll of the aboveHintThe AC motors have a high power factor, has low cost, and are reliable 91). The number of terminals in an AC motor is ____________OneTwoThreeFourHintThe number of terminals in an AC motor is three they are RYB 92). The mean value of the square wave is ____________0.6370.3180.51HintThe mean value of the square wave is one 93). The peak to average power ratio of the square wave is ____________3.01 dB6.02 dB0 dBNone of the aboveHintThe peak to average power ratio of the square wave is 0 dB 94). Which one of the following cannot produce the chemical effects of current?ACDCBoth a and bNone of the aboveHintAn alternating current cannot produce the chemical effects of current 95). The DC can be converted into an AC by using _____________RectifiersInvertersBoth a and bNone of the aboveHintThe DC can be converted into an AC by using inverters 96). The electrons in _____________ current moves only in one directionDirectAlternatingBoth a and bNone of the aboveHintThe electrons in direct current move only in one direction 97). The stability problems are less in _____________ servomotorsDirectAlternatingBoth a and bNone of the aboveHintThe stability problems are less in alternating current servomotors 98). The efficiency is high in _____________ current servomotorsDirectAlternatingBoth a and bNone of the aboveHintThe efficiency is high in direct current servomotors Read more about AC Motors 99). Which one of the following motors is self-starting?DirectAlternatingBoth a and bNone of the aboveHintThe direct current motors is self-starting 100). Which one of the following is a type of AC motor?Synchronous motorInduction motorAC commutator motorAll of the aboveHintThe synchronous motor, induction motor, and AC commutator motor are the types of AC motors Time is Up! Time's up

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