Alternating Current and Voltage Question & Answers September 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 1 1 and 2 2 and 3 3 and 4 Hint 2). The alternating current voltage have _______________ Phase Neutral Both a and b None of the above Hint 3). Which one of the following requires for transmission? AC voltage DC voltage Both a and b None of the above Hint 4). Which one of the following doesn’t have amplitude? AC voltage DC voltage Both a and b None of the above Hint 5). The passive parameter in an AC voltage is _________ Impedance Resistance Both a and b None of the above Hint 6). The ratio of real power divided by apparent power is known as _____________ Apparent power Power factor Reactive factor None of the above Hint 7). The expression for capacitive reactance is given by _____________ 1/ꙍC ꙍL WC None of the above Hint 8). The ratio f reactive power divided by apparent power is known as __________ Apparent power Power factor Reactive factor None of the above Hint 9). Which one of the following voltages is obtained from a generator? AC voltage DC voltage Both a and b None of the above Hint 10). Which one of the following voltages is unidirectional? AC voltage DC voltage Both a and b None of the above Hint 11). Which one of the following currents is discovered by Thomas Edison? AC DC Both a and b None of the above Hint 12). Which one of the following currents is discovered by Nikola Tesla? AC DC Both a and b None of the above Hint 13). The expression for inductive reactance is given by _____________ 1/ꙍC ꙍL WC None of the above Hint 14). The expression for power loss is equal to ___________ IR I^2 * R 2R 1/R Hint 15). In India the electricity standards are _____________ 10 volts and 50 hertz 30 volts and 50 hertz 20 volts and 50 hertz 230 volts and 50 hertz Hint 16). In US the electricity standards are _____________ 10 volts and 50 hertz 30 volts and 50 hertz 120 volts and 60 hertz 230 volts and 50 hertz Hint 17). How many cycles does AC produce per second? 10 cycles 20 cycles 30 cycles 50 cycles Hint 18). The period of a wave is related to ___________ quantity Rate Time Frequency None of the above Hint 19). The frequency of a wave is related to ___________ quantity Rate Time Frequency None of the above Hint 20). Which one of the following is expressed in seconds per cycle? Rate Time Period None of the above Hint 21). Which one of the following is expressed in cycles per second? Frequency Time Period None of the above Hint 22). The expression for voltage amplitude is given by _____________ 1/ꙍC IꙍL WC None of the above Hint 23). The frequency is _________ if the period is longer Higher Lower Constant Moderate Hint 24). The period is _________ if the frequency is higher Higher Lower Constant Moderate Hint 25). What is the unit to measure bandwidth? Ohms Bits/sec Hz None of the above Hint Alternating Current and Voltage Important MCQs 26). The induced EMF is categorized into ________________ One Two Three Four Hint 27). The statically induced EMF is categorized into _______________ One Two Three Four Hint 28). In _______________ phase the power supplies through one conductor Single Two Three None of the above Hint 29). The number of wires required for completing the single-phase circuit is ____________ One Two Three Four Hint 30). The single-phase alternating current circuit carries ____________ 100 volts 110 volts 200 volts 230 volts Hint 31). In which one of the following phases the efficiency is high? Single Double Three None of the above Hint 32). In _______________ phase the power supplies through three conductors Single Two Three None of the above Hint 33). Which one of the following phases is more economical? Single Double Three None of the above Hint 34). The loss is maximum in __________ phase Single Double Three None of the above Hint 35). The phase impedances in balanced load are equal in __________ Phase Magnitude Both a and b None of the above Hint 36). The transmission efficiency is high in __________ phase system Single Double Three None of the above Hint 37). The cross-sectional area of conductors are large in _________ phase system Single Double Three None of the above Hint Read more about Electrical Conductors 38). In which one of the following voltage the polarity is fixed? AC voltage DC voltage Both a and b None of the above Hint 39). The number of wires required for completing the three-phase circuit is ____________ One Two Three Four Hint 40). Which one of the following is easier to measure? AC voltage DC voltage Both a and b None of the above Hint 41). Which one of the following is easier to amplify? AC voltage DC voltage Both a and b None of the above Hint 42). The RMS value of the sine waveform is __________ 1.414 0.7071 1.11 None of the above Hint 43). The crest factor value of sine waveform is ____________ 1.414 0.7071 1.11 None of the above Hint 44). The three-phase alternating current circuit carries ____________ 100 volts 110 volts 200 volts 415 volts Hint 45). The form factor value of sine waveform is ____________ 1.414 0.7071 1.11 None of the above Hint 46). The ratio of RMS value divided by average value is known as ____________ factor Peak Form Crest None of the above Hint 47). The ripple factor is defined as a ratio of _______________ Peak voltage/DC voltage Peak voltage/AC voltage (RMS voltage/DC voltage)*100 None of the above Hint 48). Which one of the following phase networks is complicated? Single Double Three None of the above Hint 49). The RMS value of the triangular waveform is __________ 1.414 0.7071 0.577 None of the above Hint 50). The crest factor value of the triangular waveform is ____________ 1.414 0.7071 1.732 None of the above Hint Alternating Current and Voltage MCQs for Quiz 51). The form factor value of the triangular waveform is ____________ 1.414 0.7071 1.154 None of the above Hint 52). The mean value of the sine wave is ____________ 0.637 0.318 0.5 1 Hint 53). The peak to average power ratio of sine wave is _______________ 3.01 dB 6.02 dB 4.77 dB None of the above Hint 54). The ratio of peak value divided by RMS value is known as ____________ factor Peak Form Crest None of the above Hint 55). The power factor of the series resonance circuit is ________________ Zero Infinity One Unity Hint 56). The RMS value of the square waveform is __________ 1.414 0.7071 0.577 1 Hint 57). The crest factor value of the square waveform is ____________ 1.414 0.7071 1 None of the above Hint 58). The form factor value of the square waveform is ____________ 1.414 0.7071 1.154 One Hint 59). The mean value of the half-wave rectified sine is ____________ 0.637 0.318 0.5 1 Hint 60). Which one of the following circuits magnifies voltage? Series resonance Parallel resonance Both a and b None of the above Hint 61). Which one of the following circuits is also known as the acceptor circuit? Series resonance Parallel resonance Both a and b None of the above Hint 62). The power factor at resonance is unity in ______________ circuit Series RLC Parallel RLC Both a and b None of the above Hint 63). The ratio of inductor voltage or capacitor voltage by supply voltage is known as ___________ factor Quality Crest Peak None of the above Hint 64). The RMS value of saw-tooth waveform is __________ 1.414 0.7071 0.577 1 Hint 65). The crest factor value of saw-tooth waveform is ____________ 1.732 0.7071 1 None of the above Hint 66). The form factor value of saw-tooth waveform is ____________ 1.414 0.7071 1.154 one Hint 67). The mean value of full-wave rectified sine is ____________ 0.637 0.318 0.5 1 Hint 68). The peak to average power ratio of full-wave rectified sine is ____________ 3.01 dB 6.02 dB 4.77 dB None of the above Hint 69). Which one of the following circuits magnifies current? Series resonance Parallel resonance Both a and b None of the above Hint 70). Which one of the following circuits is also known as the rejector circuit? Series resonance Parallel resonance Both a and b None of the above Hint 71). The ratio of bandwidth divided by resonant frequency is known as _____________ Quality factor Crest factor Selectivity None of the above Hint 72). What is the unit of self-inductance? Ohm Henry Ampere None of the above Hint 73). How many types of inductance are there? One Two Three Four Hint 74). The mean value of triangular wave is ____________ 0.637 0.318 0.5 1 Hint 75). The peak to average power ratio of half-wave rectified sine is ____________ 3.01 dB 6.02 dB 4.77 dB None of the above Hint Alternating 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/√LC 1/LC 1/√RC None of the above Hint 77). Which one of the following is a capacitive reactance equation? 1/ꙍC 1/LC 1/RC None of the above Hint 78). Which one of the following is an inductive reactance equation? 1/ꙍC 1/ꙍL 1/RC None of the above Hint 79). The root mean square of the current is known as ______________ RMS current RMS voltage Resonant frequency None of the above Hint 80). How many ways are there to measure the alternating current and voltage? One Two Three Four Hint 81). Which one of the following is a current expression for angular velocity? ꙍ=2πf ꙍ=2f ꙍ=8πf None of the above Hint 82). Which one of the following is also known as the amplitude factor? Resonance factor Crest factor Form factor None of the above Hint 83). The peak to average power ratio of the triangular wave is ____________ 3.01 dB 6.02 dB 4.77 dB None of the above Hint 84). The root mean square of the voltage is known as ______________ RMS current RMS voltage Resonant frequency None of the above Hint 85). What are the advantages of an alternating current? Cheaper than DC Can be stepped down or stepped up by transformer Can be converted into DC by rectifier All of the above Hint 86). The magnetic field is stationary in ____________ motor AC DC Both a and b None of the above Hint 87). The armature is stationary in ______________ motor AC DC Both a and b None of the above Hint 88). Which one of the following generators doesn’t have a commutator? AC generators DC generators Both a and b None of the above Hint 89). Which one of the following motors doesn’t use brushes? AC motors DC motors Both a and b None of the above Hint 90). What are the advantages of an AC motor? High power factor Low-cost Reliable All of the above Hint 91). The number of terminals in an AC motor is ____________ One Two Three Four Hint 92). The mean value of the square wave is ____________ 0.637 0.318 0.5 1 Hint 93). The peak to average power ratio of the square wave is ____________ 3.01 dB 6.02 dB 0 dB None of the above Hint 94). Which one of the following cannot produce the chemical effects of current? AC DC Both a and b None of the above Hint 95). The DC can be converted into an AC by using _____________ Rectifiers Inverters Both a and b None of the above Hint 96). The electrons in _____________ current moves only in one direction Direct Alternating Both a and b None of the above Hint 97). The stability problems are less in _____________ servomotors Direct Alternating Both a and b None of the above Hint 98). The efficiency is high in _____________ current servomotors Direct Alternating Both a and b None of the above Hint Read more about AC Motors 99). Which one of the following motors is self-starting? Direct Alternating Both a and b None of the above Hint 100). Which one of the following is a type of AC motor? Synchronous motor Induction motor AC commutator motor All of the above Hint Time is Up! Time's up
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