JNTU ONLINE EXAMINATIONS [Mid 1 - em]

1. Which one is classified as an integratinginstrument? [01D01]a. D'Arsonval galvanometerb. Ampere - hour meterc. Ohm - meterd. Ammeter2. The most suitable material used as springmaterial for most of the applications, except inlow resistancemeasurements [01D02]a. platinum silverb. phosphor - bronzec. silicon - bronzed. hard rolled silver3. At a steady state deflected position of anindicating instrument, the moving system issubjected to [01G05]a. deflecting torque onlyb. deflecting and controlling torquesc. deflecting, controlling, damping torquesd. deflecting and controlling torques4. An instrument which gives total quantity ofenergy passed through it, in a given time iscalled [01M01]a. integrating instrumentb. indicating instrumentc. recording instrumentd. digital instrument5. The controlling torque in a spring controlledmeter is proportional to [01M02]a. thetab. %2c.1/thetad. 1/ %26. The movement of the moving element of anelectrical indicating instrument is dependenton [01M03]a. restoring torqueb. number of turns on the coilc. resistance of the circuitd. restoring torque, number of turns on thecoil and resistance of the circuit7. In indicating instruments, the springs aremainly used to [01S01]a. hold the pivot in positionb. conduct the current to the coilsc. control the movement of the pointerd. reduce the vibrations of the pointer8. The deflecting torque can be produced by[01S02]

a. gravity controlb. spring controlc. air frictiond. magnetically9. Operating torques in an indicatinginstrument are [01S03]a. deflecting, controlling, dampingb. deflecting, balancing, dampingc. deflecting, controlling, vibrationd. restoring, controlling, balancing10. The pointer returns to its zero position onremoving the source producing the deflectingtorque. This happensdue to [01S04]a. deflecting torqueb. controlling torquec. damping torqued. mass of pointer11. An instrument will have uniform scale onlywhen [02D01]a. deflecting torque varies directly as themagnitude of the quantity under measurementb. controlling torque varies directly asdeflecting anglec. damping torque varies directly as thedeflection angled. deflecting torque varies directly as themagnitude of the quantity undermeasurement and controllingtorque varies directly as deflecting angle12. The controlling torque in gravity controlledmeter is proportional to [02D02]a.b.sin0c.d. %13. A meter has a full scale deflection of 900at a current of 1A. The response of the meteris square law.Assuming spring control, the current for adeflection of 450 will be [02D03]a. 0.25Ab. 0.50Ac. 0.67Ad. 0.707A14. The torque of an ammeter varies assquare of the current. The instrument isgravity controlled and gives adeflection of 900 for current of 10A. The

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instrument is provided with gravity control,whatwould be the deflection? [02M04]a. 900b. 450c. 64.20d. 180021. Eddy current damping should not be usedwhere deflecting torque in the instrument isproduced due to[02M05]a. magnetic fieldb. electrostatic fieldc. thermo-electric e.m.fd. friction22. The damping torque must operate onlywhen the moving system of the indicatinginstrument is [02S01]a. actually movingb. stationaryc. just starting to moved. near its full deflection23. The force responsible for reduction ofoscillations of the pointer in an ammeter[02S02]a. controlling forceb. damping forcec. deflecting forced. vibration force24. If the damping torque is more than thecritical damping, the instrument is called[02S03]a. under dampedb. over dampedc. critically dampedd. un damped25. Air friction damping is used in theinstrument which is [02S04]a. Moving ironb. Moving coilc. Inductiond. Hot wire26. Fluid friction damping [02S05]a. can be used in horizontally mountedinstrumentsb. can be used in vertically mountedinstrumentsc. can be used in both horizontally andvertically mounted instrumentsd. can't be used in either horizontally orvertically mounted instruments

deflection for a current of 5A will be [02D04]a. 22.50b. 14.50c. 450d. 60015. A spring controlled instrument usesphosphor bronze springs to producecontrolling torque. If the ratio oflength of spring to thickness of the spring is3000 for a deflection of 900, what should bethis ratio if the scale is extended to 1200?[02D05]a. 4000b. 2250c. 2000d. 325016. A spring produces a controlling torque offor a deflection of 1200. Suppose its width andlength are made twotimes their originalvalue and the thickness is halved, the value ofcontrolling torque for the same deflection willbe [02G06]a.b.c.d.17. In indicating instruments the damping isusually adjusted [02M01]a. at critical value

b. to the value slightly below critical valuec. to the value slightly higher than criticalvalued. to any value18. Fluid friction damping can be employed[02M02]a. in vertically mounted instruments onlyb. in horizontally mounted instruments onlyc. in both vertically and horizontally mountedinstrumentsd. neither in vertically nor horizontallymounted instruments19. In eddy current damping systems, the discemployed should be of [02M03]a. conducting and magnetic materialb. conducting but non- magnetic materialc. magnetic and non - conducting materiald. non - magnetic and non - conductingmaterial20. A voltage of 220V produces a deflection of900 in a PMMC spring controlled instrument. Ifthe same

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d. damping vane in an air tight chamber32. PMMC instrument gives uniform scalebecause [03M03]a. it uses spring controlb. it uses eddy current dampingc. the deflecting torque is proportional to theinstrument currentd. it uses spring control and the deflectingtorque is proportional to the instrumentcurrent33. An advantage of a PMMC instrument isthat it is [03M04]a. free from friction errorb. has high torque/weight ratioc. has low torque/weight ratiod. can be used on both A.C. and D.C.34. The power consumption in PMMCinstruments is typically about [03M05]a. 0.25W to 2Wb. 0.25mW to 2mWc. 25μW to 200μWd. 0.25μW to 2μW35. The power consumed by a PMMC meterwith internal resistance of 500B and currentfor full scale deflectionas 100μA is [03S01]a. 0.5μWb. 5μW

c. 25μWd. 50μW36. In PMMC instruments the scale is [03S02]a. non-linearb. logarithmicc. exponentiald. uniformly divided37. The PMMC meter can measure [03S03]a. only A.C. quantitiesb. only D.C. quantitiesc. both A.C. and D.C. quantitiesd. only high frequency quantities38. If an analog PMMC 0-10A ammeter isprovided with no controlling mechanism andthe moving parts are freeto rotate, what will be the reading of theinstrument if a current of 1A (D.C.) passedthrough the moving coil( the torque producedis sufficient to overcomethe frictional losses) [03S04]a. 1Ab. the pointer will remain stationaryc. the pointer will continuously rotated. 10A

27. The current in a circuit consists of a DCcomponent of 10A superimposed on a 50Hzsinusoidal component ofrms value 10A. The reading shown by aPMMC ammeter will be [03D01]a.b. 20/3c. 10d. 10 + (10/3)28. A PMMC instrument produces a deflection900 when a current 2mA passes through itsmoving coil. Supposethe instrument is redesigned with its springconstant as before, and its permanent magnetis replaced with a new permanent magnetwhich produces twicethe flux density as before, what would bethe deflection if a current of 1mA is passedthrough the coil. The other features of thePMMC instrument remainthe same. [03D02]a. 1800b. 90c. 450d. 135029. A PMMC instrument is spring controlled,the control spring stiffness decreases byamount 0.04 % per 0C risein temperature and the strength of magnetsgoes down by 0.02 % per 0C rise intemperature. The rise in temperature is 100C.The deflection [03D03]a. decreases by about 0.2 %b. decreases by about 0.4 %c. increases by about 0.4 %d. increases by about 0.2 %30. A PMMC instrument uses a coil ofresistance 0.2B and produces full scaledeflection with a steady current of10A. If this instrument is used as anammeter, then the range of the instrument willbe zero to [03M01]a. 0.2Ab. 1Ac. 2Ad. 10A31. In PMMC instruments damping is providedby [03M02]a. the coil itselfb. separate pair of magnetsc. an aluminum frame on which the coil iswound

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45. If the connections of a moving ironvoltmeter connected in a circuit areinterchanged, then the voltmeter[04S02]a. will not give any readingb. will deflect in opposite directionc. reading will remain unaffectedd. will burnt46. Eddy current damping cannot be used formoving iron instruments because [04S03]a. weight of the instrument will increaseb. presence of permanent magnet requiredfor this purpose will affect the deflectionand hence theinstrument readingsc. size of the instrument will increased. eddy current will pass through the iron andthere by cause loss47. The deflecting torque of moving ironinstrument is proportional to [04S04]a. Ib. I2c. Id. I48. A square wave type voltage of peakmagnitude 100V is measured by a movingiron voltmeter. It will read[05D01]a. 200Vb. 50Vc. 100Vd. 400V49. A moving iron voltmeter reads low for A.C.voltages than for corresponding values of D.C.voltages. Themeter can be made to read equally for bothA.C.and D.C. voltages [05D02]a. if the resistance of the multiplier is madevery highb. if the inductance of the coil is made smallc. if the resistance of the coil is made verylarged. if the multiplier resistance is shunted bya capacitance of appropriate value to makethe circuit noninductive50. Spring controlled moving iron instrumentsexhibit a square law response resulting in anon-linear scale. Theshape of the scale can be made almostlinear by [05D03]a. keeping rate of change of inductance, Lwith deflection, % as constant

39. A moving iron voltmeter reads correctly on250V DC. If 250V, 50Hz A.C. is applied to it.What will be thereading of the voltmeter? The instrument coilhas a resistance of 500B and an inductance of1H and series non-inductive resistance is2000B [04D01]a. 248Vb. 250Vc. 252Vd. 255V40. Error due to change in frequency inmoving iron instruments, may be reduced byusing a/an [04D02]a. induction coilb. condenser of suitable value in parallelwith the swamping resistancec. condenser of suitable value in series withthe swamping resistanced. balancing circuit41. In spring controlled moving ironinstruments [04M01]a. we have uniform scaleb. we can have complete linear scale bychoosing irons of appropriate shape and sizec. we have scale cramped at the lower endand expanded at the upper end and it isnot possible toexpand the scale near zerod. we have scale expanded at the lower endand cramped at the upper end42. In MI instruments, the deflection isproportional to [04M02]a.b.c.d.43. In MI instruments, the deflecting torque isproportional to [04M03]a.b.c.d.44. A moving iron ammeter coil has few turnsof thick wire in order to have [04S01]a. high sensitivityb. effective dampingc. low resistance and large currentcarrying capacityd. large scale

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c. indicator type instruments as on panelsd. Integrated type of instrument57. Which instrument is the cheapestdisregarding the accuracy [05S03]a. PMMCb. Moving Ironc. Electrodynamometerd. Rectifier58. If r is the resistance of the voltmeter and Ris the series resistance connected in its seriesthe voltageextension range will be [06M01]a.b.c.d.59. In order to reduce errors on account oftemperature changes, the swampingresistance [06M02]a. should be made of a material having highresistance temperature co-efficientb. should be made of a material having a lowresistance temperature co-efficient with thevalue of swampingresistance equal to meter resistancec. should be made of a material having lowresistance temperature co-efficient andshould have a valueof about 20 to 30 times that of meterresistanced. should have infinite value60. A d'Arsonval movement is rated at 50μA.Its sensitivity is [06M03]a. 20000B/Vb. 200000C/Vc. 200C/Vd. can't be determined61. When selecting a meter range scale totest a circuit, you should select the range thatwill indicate near the[06S01]a. top of the scaleb. mid - point of the scalec. bottom of the scaled. trail and error average point62. For increasing the range of an ammeter,connect [06S02]a. a high value resistance in series with theammeter coilb. a high value resistance in parallel with theammeter coilc. a low value resistance in series with theammeter coil

b. keeping as constantc. keeping as constant where K is springconstantb keeping as constant51. Moving Iron Instruments when measuringvoltages or currents [05M01]a. indicate the same values of themeasurement for both ascending anddescending valuesb. indicate higher value of measured forascending valuesc. indicate higher value of measured fordescending valuesd. indicate lower value of measured forascending values52. The moving iron voltmeters indicate:[05M02]a. the same value for D.C. and A.C. voltagesb. lower values for A.C. voltages than forcorresponding D.C. voltagesc. higher values for A.C. voltages than forcorresponding D.C. voltagesd. zero value for D.C. voltages53. The frequency range of moving ironinstrument is [05M03]a. audio frequency band 20Hz to 20kHzb. very low frequency band 10Hz to 30kHzc. low frequency band 30Hz to 300kHzd. power frequencies 0 to 125hz54. Error due to change in frequency inmoving iron instrument is reduced byconnecting a condenser acrossswamping resistance. The readings of theinstrument will be independent of frequencyonly when [05M04]a. C = L/r2b. C = Lr2c. C = (Lr)d. C = L/r55. A moving iron instrument can be used forcurrent and voltage measurements [05S01]a. in A.C. circuits onlyb. in D.C. circuits onlyc. in both A.C. and D.C. circuits for any valueof frequencyd. in both A.C. and D.C. circuits forfrequencies upto about 125Hz56. Moving Iron type of Instrument can beused as [05S02]a. standard instruments for calibration of otherinstrumentsb. transfer type of instruments

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d. a low value resistance in parallel withthe ammeter coil63. For increasing the range of an voltmeter,connect [06S03]a. a high value resistance in series with thevoltmeterb. a high value resistance in parallel with thevoltmeterc. a low value resistance in series with thevoltmeterd. a low value resistance in parallel with thevoltmeter64. A 1mA ammeter has a resistance of 100B.It is to be converted to a 1A ammeter. Thevalue of shuntresistance is [06S04]a. 0.001Cb. 0.1001Bc. 100000Cd. 100C65. Swamping resistance is connected inseries with [06S05]a. the shunt to reduce temperature error inshunt ammeters.b. the ammeters to reduce errors on accountof friction.c. the meter and have a high resistancetemperature co-efficient in order to reducetemperature errors inammeters.d. the meter and have a negligibleresistance co-efficient in order to reducetemperature errors inshunted ammeters.66. A 4 - range milli ammeter having ranges of0 - 10mA, 0 - 50mA, 0 - 100mA, and 0 -500mA. It is used formeasurement of current whose magnitude isnot known. In order to prevent damage to theinstrument, the selector switch of the ammetershould be firstplaced at [06S06]a. 0 - 50mA rangeb. 0 - 100mA rangec. 0 - 10mA ranged. 0 - 500mA range67. A 1mA d'Arsonval movement has aresistance of 100B. It is to be converted to a10V voltmeter. The value ofmultiplier is [06S07]a. 999Cb. 9999C

c. 9900Bd. 990C68. A 0-300V voltmeter has an error of ±2 %of full scale deflection. If true voltage is 30V,the range of readingswill be [07D01]a. 24V - 36Vb. 29.4V -30.6Vc. 20V - 40Vd. 30V - 40V69. A 0 - 10A ammeter has guaranteedaccuracy of 1 % of full scale deflection. Thelimiting error while reading2.5 is [07D02]a. 1 %b. 2 %c. 4 %d. 3 %70. A 150V moving iron voltmeter of accuracyclass 1.0 reads 75V when used in a circuitunder standardconditions. The maximum possiblepercentage errorin the reading is [07D03]a. 0.5b. 1.0c. 2.0d. 4.071. A d'Arsonval movement has a sensitivityof 40,000B/V and its internal resistance is4000B. The resistance ofmultiplier to convert it to 1V voltmeter is[07M01]a. 44000Cb. 36000Bc. 3600Cd. 4400C72. The relative division of current through thegalvanometer and the shunt with Ayrton shunt[07M02]a. is independent of galvanometer coilresistanceb. depends upon galvanometer coil resistanceonlyc. depends upon galvanometer coil resistanceand shunt resistanced. is independent of both galvanometer coilresistance and shunt resistance73. The voltmeter of sensitivity 1000B/V isconnected across the 50kB resistor in thecircuit shown in the figure(a) . The voltmeter reading will be

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Figure(a)[07M03]a. 50Vb. 45Vc. 30Vd. 25V74. In a permanent magnet moving coilammeter the deflection of the pointer isproportional to product of fluxdensity of magnetic field produced by thepermanent magnet and the current in themoving coil. If the strength of the permanentmagnet becomes 95 % ofthe original, the meter gives erroneousreading resulting into error. This error can beclassified as [07S01]a. gross errorb. Systematic errorc. error caused by over loadingd. random error75. Systematic errors are [07S02]a. instrumental errorsb. instrumental errors and environmentalerrorsc. random errorsd. environmental error76. The maximum percentage error in thedifference of two measured currents and willbe [07S03]a. 7 %b. 1 %c. 14.5 %d. 3.5 %77. Which material is used for swampingresistance that is connected in series with theworking coil of avoltmeter? [07S04]a. constantanb. manganinc. eurekad. nichrome78. The function of a shunt in an ammeter isto [07S05]a. increase the instrument resistanceb. bypass the currentc. reduce the voltage drop across theinstrument coild. increase the current flowing through theinstrument coil79. A moving coil instrument has a resistanceof 0.6B and a full scale current of 0.1A. Toconvert it into anammeter of 0-15A range, the resistance of the

shunt should be [07S06]a. 0.6Cb. 0.06Cc. 0.1Cd. 0.004B80. Measuring range of a voltmeter can beextended by using [07S07]a. high shunt resistanceb. high series resistancec. low shunt resistanced. low series resistance81. In the figure shown figure (a) the voltmeterhas a total resistance of 50kB and reads 50V.the voltage V isthenFigure(a)[07S08]a. 50Vb. 25Vc. 100Vd. 75V82. An Electrostatic voltmeter with springcontrol gives a full scale deflection of 800when 0.2kV is applied. Thecapacitance increases uniformly with angulardeflection from 20pF for zero deflection to100pF for 800. The deflection for 1.5kV will be[08D01]a. 200b. 300c. 45 degreesd. 60083. A hypothetical electrostatic voltmeter withspring control is designed with one fixed andanother movableplate. Both plates are in the form of circle withone plate over the other so as to produce arotary motion. If a voltage is applied betweenthem, no rotary motionis produced because [08D02]a. there is no change in the voltageb. there is no change in the capacitanceirrespective of the relative position of thetwo platesc. the spring force is very larged. the applied voltage is small to produce anynoticeable deflection84. Frequency up to which the electrostaticinstruments can be used without serious lossof accuracy is [08M01]a. 100Hzb. 100kHz

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92. Electrostatic instruments are mainly usedfor measurement of [08S06]a. heavy currentsb. low currentsc. low voltagesd. high voltages93. Which of the following instrument is freefrom hysteresis and eddy current errors?[08S07]a. Moving Ironb. electrostaticc. moving coil dynamometerd. PMMC94. A quadrant type electrostatic instrumentuses two types of connections (i) Hetrostaticand (ii) Idiostatic. Anexternal battery is [08S08]a. used for Idiostatic connectionb. used for Hetrostatic connectionc. used for both Idiostatic and Hetrostaticconnectionsd. neither used for Hetrostatic nor Idiostaticconnection95. The size of electrostatic voltmeter is largeas compared with correspondingelectromagnetic voltmetersbecause [08S09]a. they are used for measurement of highvoltagesb. energy density in an electrostatic field isconsiderably smaller than that in anelectromagnetic fieldc. their frequency range is smallerd. they have a high dielectric loss96. The range of electrostatic voltmeter canbe extended by using [08S10]a. a capacitor in series with the voltmeterwhose capacitance is greater than thecapacitance of the voltmeterb. a capacitor in series with the voltmeterwhose capacitance is smaller than thecapacitance of thevoltmeterc. a resistor in series with the voltmeterd. an inductor in series with the voltmeter97. Which of the following instruments is notused for measuring current? [08S11]a. Moving Ironb. electrostaticc. Hot wired. PMMC

c. 1MHzd. 10MHz85. Quadrant type electrostatic instrumentscan be used for measurement of A.C. voltage[08M02]a. only when Hetrostatically connectedb. only when Idiostatically connectedc. in either Hetrostatically or Idiostaticallyconnectedd. not at all86. An electrostatic voltmeter draws a smallvalue of current on D.C [08M03]a. under steady state conditionirrespective of the applied voltageb. when switched on irrespective of theapplied voltagec. when measuring low voltagesd. when measuring high voltages87. In electrostatic instruments, deflectingtorque is proportional to [08S01]a. Vb. V2c. 1/Vd. 1/V288. Electrostatic instruments work on theprinciple of [08S02]a. repulsion of unlike polesb. attraction of like polesc. attraction between positive and negativecharged. repulsion between negative charges89. Electrostatic instruments are suitable forthe measurement of [08S03]a. A.C. and D.C. voltagesb. A.C. voltages and currentsc. D.C. voltages and currentsd. A.C. voltages only90. The main advantage of electrostaticinstruments is that [08S04]a. it is suitable for measurement of very lowvoltage and currentsb. it is suitable for measurement of very lowvoltage and very high currentsc. it takes negligible current from thesourced. its construction is very robust and cheap91. Electrostatic type of instruments areprimarily used as [08S05]a. ammetersb. watt metersc. voltmetersd. ohmmeters

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98. A short circuiting link is provided on thesecondary side of a current transformerbecause [09D01]a. When the secondary winding of the C.T. isshort circuited by the link with the primarywinding energized, avery high current flows on the primary sideb. When the secondary winding of the C.T.is short circuited by the link with theprimary windingenergized, it is possible to make anyadjustments inthe secondary winding circuit like replacing afaulty ammeterc. When the short circuiting link is opened withthe secondary winding open circuited, thecurrent on the primaryside falls to almost zero.d. When the secondary winding of the C.T. isshort circuited by the link with the primarywinding energized, it isnot possible to make any adjustments in thesecondarywinding circuit like replacing a faulty ammeter99. When the secondary winding of a currenttransformer is open-circuited with primarywinding energized[09D02]a. the whole of the primary currentproduces large value of flux in the corethere by producing a largevoltage in the secondary winding.b. When the large magnetizing force is takenoff it leaves a small value of residualmagnetismc. the whole of the primary current producessmall value of flux in the core there byproducing a small voltage inthe secondary winding.d. a very small current flows on the primaryside100. While using a CT it is essential tomaintain at all times a closed circuit on thesecondary side in order to[09M01]a. reduce power lossesb. avoid demagnetizationc. avoid dangerously high emfs for both theoperator and the transformer insulationd. avoid dangerously high currents

101. A current transformer has a rating of100/5A. its magnetizing and loss componentsof the exciting currentare 1A and 0.6A respectively and secondwinding is purely resistive, its transformationratio at rated current is [09M02]a. 20.12b. 20.2c. 200.2d. 2000.2102. The advantage of instrumenttransformers over ammeter shunts andvoltmeter multipliers are [09S01]a. the metering circuit is electrically isolatedfrom the power circuit there by providingsafety in use to both theinstruments and the operatorb. small power losses in comparison to thosein ammeter shunts and voltmeter multipliersc. the instrument transformers can be used forboth dc as well as ac measurementsd. the metering circuit is electricallyisolated from the power circuit and smallpower losses incomparison to those in ammeter shuntsand voltmetermultipliers103. The number of turns on the primary ofcurrent transformer is usually [09S02]a. 1 to 5b. 10 to 20c. 20 to 100d. 100 to 500104. The nominal ratio of a currenttransformer [09S03]a. primary winding current / secondarywinding currentb. rated primary winding current / ratedsecondary winding currentc. number of secondary winding turns /number of primary winding turnsd. primary winding voltage / secondarywinding voltage105. The burden of current transformer isexpressed in terms of [09S04]a. secondary winding currentb. VA rating of transformerc. Voltage, current and power factor ofsecondary winding circuitd. Primary winding current106. The current in the primary winding of acurrent transformer depends upon [09S05]

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a. burden of the transformer secondarywindingb. load connected to the system in whichthe C.T. is installedc. both burden of the transformer secondarywinding and load connected to the systemd. power factor of the secondary winding107. Clamp on meters are used because[09S06]a. it is possible to measure current flowingin a line without breaking the circuitb. their accuracy is highc. it is not possible to measure voltage withoutthemd. they are cheap108. When the secondary winding of apotential transformer is suddenly open-circuited with primary windingenergized [10D01]a. Large voltages are produced in thesecondary winding may be a safety hazard tooperating personnelb. The large voltages so produced mayrapture the insulationc. The primary winding draws only the noload currentd. a very high current flows on the primaryside109. In case of potential transformers with theincrease in load on secondary side [10M01]a. both of the ratio error and phase angleerror increasesb. the ratio error increases but phase angleerror decreasesc. the ratio error decreases but phase angleerror increasesd. both of the ratio error and phase angle errordecreases110. High A.C. voltages are usually measuredwith [10S01]a. magnetic voltmeterb. inductive voltameterc. Potential Transformers with voltmeterd. Current Transformers with voltmeter111. The transformation ratio of a potentialtransformer is defined as the ratio of [10S02]a. primary winding voltage / secondarywinding voltageb. rated primary winding voltage / ratedsecondary winding voltagec. number of primary winding turns / numberof secondary winding turns

d. primary winding current / secondarywinding current112. Capacitive potential transformers areused [10S03]a. for primary winding phase voltages below100kVb. for keeping the value of transformationratio constant irrespective of the burdenby making certainadjustmentsc. because they are cheaper than theelectromagnetic transformer below a certainvoltage ranged. because they are costlier than theelectromagnetic transformer above a certainvoltage range113. The size of potential transformers[10S04]a. is same as that of power transformers ofthe same VA ratingb. is much greater than that of powertransformers of the same VA ratingc. is smaller than that of power transformers ofthe same VA ratingd. is much smaller than that of powertransformers of the same VA rating114. The ratio of transformation in the case ofpotential transformers [10S05]a. increases with increase in power factor ofsecondary burdenb. remains constant irrespective of powerfactor of secondary burdenc. decreases with increase in power factorof secondary burdend. no effect of power factor on the ratio oftransformation115. Which of the following you will prefer toextend the range of an A.C. voltmeter [10S06]a. low series resistanceb. high resistance in parallelc. Current transformerd. Potential transformer116. A current transformer has a phase errorof +30. The phase angle between the primaryand secondarycurrents is [11M01]a. 30b. 177 degreesc. 1800d. 1830

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117. A current transformer has a rating of1000/5A. It's magnetizing current and losscomponent of excitingcurrent are 10A and 6A respectively. Thephaseangle between secondary winding inducedvoltage and current is 300. The phase angleerror of the transformeris [11M02]a. 0.650b. 0.305 degreesc. 0.4960d. 0.9650118. The ratio and phase angle errors inpotential transformers may be reduced by[11M03]a. increasing the exciting currentb. increasing the resistance and leakagereactance in the transformerc. by not employing turns compensationd. decreasing the resistance and leakagereactance in the transformer119. In case of potential transformers [11M04]a. the phase angle error is always positiveb. the phase angle error is always negativec. the phase angle error is usually zerod. the phase angle error is positive whenthe secondary winding voltage reversedleads the primarywinding voltage and is negative when thesecondarywinding voltage reversed lags the primarywinding voltage120. The ratio and phase angle errors in awell designed current transformer are keptwithin the specified limitsby [11S01]a. in-built compensating capacitorsb. mild steel corec. some fractional turnsd. ferrite core121. The ratio error in the current transformeris attributed to [11S02]a. magnetizing component of no- load currentb. energy component of excitation currentc. leakage fluxd. power factor of the primary122. The errors in current transformers can bereduced by designing them with [11S03]a. high permeability and low loss corematerials, avoiding any joints in the coreand also keeping the fluxdensity to a low value

b. primary and secondary windings keepingclose to each otherc. large cross-sections for both primary andsecondary winding conductorsd. primary and secondary windings keepingaway from each other123. Turns compensation is used in currenttransformers primarily for reduction of [11S04]a. phase angle errorb. ratio errorc. both ratio and phase angle errorsd. ratio error, reduction in phase angleerror is incidental124. The power factor in a single circuit is =P/VI, where P is the power read by awattmeter, V is the voltageread by a voltmeter and I is the currentread by an ammeter. All the three instrumentshave a limiting error of ±1 %. The power factorof the circuits canbe known if only one meter i.e. anelectrodynamometer type power factor meterhaving a limiting error ±1 % used. Thepreferred method is to use asingle instrument like a power factormeter rather than using 3 instrumentsbecause the error when using wattmeter,voltmeter and ammeter is[12D01]a. ±2 %b. }3 %c. ±1 %d. -1 %125. Which of the following statements iscorrect? [12D02]a. the moving iron power factor meter isgenerally used as it has got large operatingforceb. the moving iron power factor meter isgenerally used because it gives scaleextending over a full scalec. the dynamometer type of power factormeter is generally used because it is moreaccurate than moving ironpower factor meterd. the moving iron power factor meter isgenerally used as it has got largeoperating force and it givesscale extending over a full scale126. Which of the following statements is nottrue for a power factor meter? [12M01]

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a. It consists of two coils mounted at rightangles to each otherb. Balanced position depends upon theresulting torque developed by the two coilsc. The restoring torque is provided by acontrol springd. The deflection is proportional to the phaseangle between field coil and crossed coil127. There will be serious errors, if powerfactor of non-sinusoidal waveforms ismeasured byelectrodynamometer power factor meters.This is true for[12M02]a. only single phase metesb. only three phase metesc. both single and three phase metesd. neither single phase nor three phasemeters128. The controlling torque in single phasepower factor meters provided by [12S01]a. spring controlb. gravity controlc. stiffness of suspensiond. fluid friction129. A dynamo meter type power factor meterhas [12S02]a. one current circuit and one pressure circuitb. one current circuit and two pressurecircuitsc. one pressure circuit and two current circuitsd. two current circuits and two pressurecircuits130. The two pressure coils of a single phasedynamometer type power factor meter are ofthe [12S03]a. same dimensions and same number ofturnsb. same dimensions but different number ofturnsc. same number of turns but differentdimensionsd. different number of turns and differentdimensions131. A 53Hz reed type frequency meter ispolarized with D.C. The new range offrequency meter is [13D01]a. 106Hzb. 26.5Hzc. 53Hzd. 212Hz132. Essentially, the reed frequency is[13S01]

a. oscillatory measuring instrumentb. vibration measuring instrumentc. deflection measuring instrumentd. recording measuring instrument133. In a reed type frequency meter all thereeds [13S02]a. have the same natural frequencyb. have different natural frequenciesc. have different natural frequencies butdifference in natural frequencies ofadjacent reeds is }0.5Hzd. have different natural frequencies butdifference in natural frequencies of adjacentreeds is ±5Hz134. Weston frequency meter operates on theprinciple [13S03]a. variation of impedance of an inductivecoil circuit with the variation in supplyfrequencyb. phenomenon of mechanical resonancec. phenomenon of electrical resonanced. variation of impedance of capacitive circuitwith the variation in supply frequency135. Vibrating reeds are employed in [13S04]a. frequency meterb. pf meterc. synchroscoped. megger136. For a three phase, moving ironsynchroscope, f2 frequency of incomingmachine f1 frequency of bus bars.At equilibrium ,where . If f' is positive [14M01]a. the incoming machine is fasterb. the incoming machine is slowerc. the incoming machine is slower and can'tbe synchronized to the busbarsd. the incoming machine can be synchronizedto the busbars137. An alternator is being synchronized tothe busbars whose frequency is 50Hz. Thebulb of the synchroscopeflickers at a frequency of 10Hz. The frequencyof the alternator is [14M02]a. 60Hzb. 40Hzc. 60Hz or 40Hzd. 50Hz138. In a Weston type synchroscope the[14M03]a. fixed coils are connected across incomingalternator

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a. to reduce eddy current losses inconductorsb. to reduce mechanical lossesc. to reduce hysteresis lossesd. to reduce iron losses144. A capacitor is connected across a portionof resistance of the multiplier in order to makethe pressure coilcircuit non-inductive. The value of thisresistance is `r' while the total resistance andinductance of the pressure coil circuit arerespectively RP and L.The value of capacitance C is [15D03]a. 0.41 L/r2b. 0.41 L/{R_P}2c. L/{RP}2d. L/r2145. In a low power factor wattmeter acapacitor is connected across a part of seriesresistance in the pressurecoil circuit. This is done in order to [15D04]a. neutralize the capacitive effect of pressurecoilb. compensate for the error caused byinductance of pressure coilc. compensate for the error caused by powerloss in the pressure coild. compensate for the error caused by powerloss in the current coil146. In electrodynamometer type ofwattmeters, the inductance of pressure coilcircuit produces error [15D05]a. which is constant irrespective of the powerfactor of the loadb. which is higher at low power factorsc. which is lower at low power factorsd. which is zero at low power factors147. A dynamometer type wattmeter respondsto the [15M01]a. average value of active powerb. average value of reactive powerc. peak value of active powerd. peak value of reactive power148. When measuring power with anelectrodynamometer wattmeter in a circuitwhere the load current is small[15M02]a. the current coil should be connected onthe load sideb. the pressure coil should be connected onthe load sidec. the current coil should be connected on thesupply side

b. moving coil is connected across thebusbarsc. fixed coils are connected across busbarsand moving coil is connected across incomingalternatord. fixed coils are connected acrossincoming alternator and moving coil isconnected across busbars139. The synchroscope is an instrument for[14S01]a. checking the voltages of the two circuitsb. checking of phase sequence of the twocircuitsc. indicating differences of phases andfrequencies of two circuit voltagesd. checking power factor of the two circuits140. Which of the following statements iscorrect? [14S02]a. Dynamometer type synchroscope is morecommonly used as it is more accurate thanmoving iron typeb. The moving iron syncroscope is morerobust in construction and suitable forcontinuous operationc. Weston type synchroscope is morecommonly used, as it is cheap in cost androbust in constructiond. The Dynamometer type syncroscope ismore robust in construction and suitable forcontinuous operation141. An electro - dynamic part is introduced inWeston type syncroscope for synchronizingan incoming machineto the bus bars for [14S03]a. checking the voltage of two circuitsb. checking the phase sequence of the twocircuitsc. checking whether the incoming machineis fast or slowd. indicating power factor of the two circuits142. A compensated wattmeter has itsreading corrected for error due to [15D01]a. the frequencyb. frictionc. power consumed in current coild. power consumed in pressure coil143. In electrodynamometer type ofwattmeters, current coils designed for carryinglarge currents use standardwire or laminated conductors [15D02]

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d. across the pressure coil154. A wattmeter is reading backwards in anexperiment. Upscale reading can be obtainedby reversing [15S01]a. pressure coil connection onlyb. current coil connection onlyc. both pressure and current coil connectionsd. either the pressure coil or current coilconnections155. In dynamo meter type of wattmeter,which of the coil is split into two parts [15S02]a. pressure coilb. current coilc. both pressure and current coilsd. neither pressure coil nor current coil156. Which of the following type of damping ismost commonly employed in thedynamometer type wattmeter[15S03]a. fluid frictionb. eddy currentc. air frictiond. both air and fluid friction157. The moving coil in a dynamometerwattmeter is connected [15S04]a. in series with the fixed coilb. across the supplyc. in series with the loadd. across the load158. The dynamometer type wattmeter isshielded against stray magnetic fields by[15S05]a. earthing the meterb. providing neutral wire connectionc. housing the meter in a soft iron cased. making meter components of non -magnetic materials159. In an electrodynamometer type ofwattmeter [15S06]a. the current coil is made fixedb. the pressure coil is fixedc. any of the two coils i.e. current coil orpressure coil can be made fixedd. both the coils should be movable160. In a VAR meter, the angle betweenvoltage and instrument voltage [16D01]a. zerob. 3/6c. 3/4d. P/2161. Which of the following statements is trueabout two wattmeter method of powermeasurement in 3 - Q

d. it is immaterial whether the pressure coil orcurrent coil is connected on the load side149. When measuring power with anelectrodynamometer wattmeter in a circuitwhere the load current is large[15M03]a. the current coil should be connected on theload sideb. the pressure coil should be connectedon the load sidec. the pressure coil should be connected onthe supply sided. it is immaterial whether the pressure coil orcurrent coil is connected on the load side150. When measuring power with anelectrodynamometer wattmeter in a circuithaving a low power factor[15M04]a. the current coil should be connected on theload sideb. the pressure coil should be connectedon the load sidec. the current coil should be connected on thesupply sided. a compensated wattmeter with pressurecoil connected on the load side should beused151. Ordinary electro - dynamo meter typewattmeter is not suitable for measurement ofpower in low powerfactor circuits owing to [15M05]a. small deflecting torqueb. introduction of large error because ofpressure coil at low power factorc. introduction of large error due to current coilat low power factord. small deflecting torque and introductionof large error because of pressure coil atlow power factor152. In a low power factor wattmeter, thepressure coil is connected [15M06]a. on the load side of the current coilb. on the supply side of the current coilc. either on the load side or supply side of thecurrent coild. neither on the load side nor supply side ofthe current coil153. In a low power factor wattmeter thecompensating coil is connected [15M07]a. in series with the current coilb. in series with the pressure coilc. across the current coil

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circuit? [16D02]a. Power can be measured using twowattmeter method only for star connected 3 -J circuitb. When two wattmeters show identicalreadings, the power factor is 0.5c. When power factor is unity, one of thewattmeter reads zerod. When the readings of the twowattmeters are equal but opposite sign,the power factor is zero162. Two wattmeter method is employed tomeasure power in 3 - Q balanced system withcurrent coilsconnected in the A and C lines. The phasesequence isABC. If the wattmeter with its current coil in A- phase line reads zero, then the power factorof the 3 - Q load willbe [16D03]a. zero laggingb. zero leadingc. 0.5 laggingd. 0.5 leading163. The ratio of the readings of twowattmeters connected to measure power in abalanced 3 - Q load is 5:3 andthe load is inductive. The power factor ofthe load is [16D04]a. 0.917 leadingb. 0.917 laggingc. 0.6 leadingd. 0.6 lagging164. and are the instantaneous line to neutralvoltages and , and iB are instantaneous linecurrents in a balanced3 - Qcircuit, the computation will yield a quantityproportional to [16D05]a. active powerb. power factorc. reactive powerd. complex power165. Two wattmeters connected to measurethe power in a 3 - Q, balanced deltaconnected load read andanotherrespectively. If the same load be connected instar the wattmeters would read [16M01]a.b.c.

d.w1=4kw;w2=5kw166. A delta connected 3 - Q inductive loaduses the two wattmeter method to measure itstotal power. Onewattmeter reads 12kW and another 18kW.The pfof the load is [16M02]a. 0.93b. 0.9c. 0.945d. 0.93167. In a two wattmeter method of measuringpower in a 3-Q system one of the wattmetersreads negativeimplying [16M03]a. wattmeter connection faultyb. load is unbalancedc. power flow is in the reverse directiond. power factor is less than 0.5168. In two wattmeter method of powermeasurement, one of the wattmeters will shownegative reading whenthe load power factor angle is strictly[16M04]a. less then 300b. less than 600c. greater than 300d. greater than 600169. While measuring power in a 3 - Q load bytwo wattmeter method, the readings of the twowattmetrs will beequal and opposite when [16M05]a. power factor is unityb. load is balancedc. phase angle is between 600 and 900d. the load is purely inductive170. In two wattmeter method of measuring 3- Q power, power factor is 0.5, then one of thewattmeter will read[16M06]a. W/2b. zeroc. Wd. W/171. The minimum number of wattmetersrequired to measure the real power in an Nphase system withunbalanced load is [16S01]a. (N - 1)b. Nc. (N + 1)d. (N - 2)

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172. The power measurement in balanced 3-Q circuit can be done by [16S02]a. one wattmeter method onlyb. two wattmeter method onlyc. three wattmeter method onlyd. using one, two and three wattmetermethods173. The power delivered to a 3 - Q load canbe measured by the use of 2 wattmeters onlywhen the [16S03]a. load is balancedb. load is unbalancedc. 3 - Q load is connected to the sourcethrough 3 - wiresd. 3 - J load is connected to the sourcethrough 4 - wires174. In the measurement of 3 - Q power bytwo - wattmeter method, if two wattmeterreadings are equal, thepower factor of the circuit is [16S04]a. 0.8laggingb. 0.8 leadingc. zerod. unity175. W1 and W2 are the readings of twowattmeters used to measure power of a 3 - Qbalanced load. Thereactive power drawn by the load is [16S05]a.b.c.d.√3(w1-w2)176. In three phase power measurement bytwo wattmeter method the power factor of loadwill be [16S06]a.√(w1-w2)/(w1+w2)b.c.d.177. In the two wattmeter method forbalanced load, the readings of wattmetrs are3kW and 1kW respectively,the latter being obtained after reversing theconnections to the current coil of onewattmeter, the power measured is [16S07]a. 4Wb. 2Wc. 1Wd. 0.5W178. In the two wattmeter method forbalanced load, the readings of wattmetrs are3kW and 1kW respectively,the latter being obtained after reversing the

connections to the current coil of onewattmeter, the power factor measured is[16S08]a. 0.095b. 0.184c. 0.277d. 0.526179. The current in the pressure coil of asingle phase energy meter is proportional to[17M01]a. load currentb. supply voltagec. supply voltage and line currentd. active power drawn by the load180. The pressure coil of a single phaseenergy meter is wound on [17M02]a. one limb of laminated coreb. both the limbs of the laminated core withdifferent number of turnsc. both the limbs of the laminated core withsame number of turnsd. the centre of the limb on the laminatedcore181. The current coil of single phase energymeter is wound on [17M03]a. one limb of laminated coreb. both the limbs of the laminated core withdifferent number of turnsc. both the limbs of the laminated core withsame number of turnsd. the centre of the limb on the laminated core182. Reactive volt ampere hours in a 3 - Qbalanced load can be measured by [17M04]a. using one single element watt - hour meterb. two wattmeter difference methodc. both using one single element watt -hour meter and two wattmeter differencemethodsd. three wattmeter method183. The most commonly used energy meter[17M05]a. electrolyitic meterb. clock meterc. motor meterd. all of the meters find equal applications184. Light load adjustments for induction typeenergy meters are usually done at [17M06]a. 10 % of full load currentb. 5 % of full load currentc. 50 % of full load currentd. 1 % of full load current

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192. If an induction type energy meter runsfast, it can be slowed by [17S08]a. lag adjustmentb. light load adjustmentc. by adjusting the position of braking magnetand making it come closer to the centre of thediscd. by adjusting the position of brakingmagnet and making it move away from thecentre of the disc193. Creeping in a single phase induction typeenergy meter may be due to [17S09]a. overcompensation for frictionb. low voltagesc. holes in the discd. large load current194. In an induction type energy meter[17S10]a. there is no brake magnetb. there is a control springc. disc revolves continuouslyd. there is no temperature error195. In an energy meter the braking device isprovided to produce braking torque so that the[18D01]a. energy meter can be brought to standstillb. meter creeping be checkedc. moving system of the instrument (armature or disc) rotates at a particularspeed for a particular rateof energy consumption at any timed. energy meter can rotate at high speed196. The braking torque provided by apermanent magnet in a single phase energymeter is proportional to the[18M01]a. square of the flux of the permanentmagnetb. flux of the permanent magnetc. square of the speed of the meterd. square of the distance of the permanentmagnet from the centre of the revolving disc197. The braking torque provided by apermanent magnet in a single phase energymeter can be changed by[18M02]a. providing a magnetic shunt and changingits positionb. changing the distance of the permanentmagnet from the centre of the revolving discc. providing a magnetic shunt andchanging its position and changing thedistance of the permanent

185. The three phase four wire energy meteris used to measure [17S01]a. three phase unbalanced energyb. three phase balanced energyc. two phase energyd. single phase energy186. The pressure coil of a single phaseenergy meter consists of [17S02]a. more number of turns of fine wireb. less number of turns of fine wirec. less number of turns of thick wired. more number of turns of thick wire187. The coil of series magnet in a singlephase energy meter consists, [17S03]a. thin wire of few turnsb. thick wire of few turnsc. thin wire of more turnsd. thick wire of more turns188. Meter constant of energy meter is givenby [17S04]a. rev./kWb. rev./kWhc. rev./Wd. rev./Var189. Electrolyitic meter is basically is a/an[17S05]a. D.C. ampere - hour meterb. D.C. watt - hour meterc. A.C. energy meterd. A.C. ampere - hour meter190. In single phase induction type energymeter, compensation for static friction isprovided by [17S06]a. shading bands which are actuated toprovide a constant torque irrespective ofloadb. lag circuitsc. drilling holes in the discd. providing a magnetic shunt and changingits position191. In a household , single phase inductiontype energy meter, the meter can be reversedby [17S07]a. reversing the supply terminalsb. reversing the load terminalsc. opening the meter connections andreversing either the potential coil terminalsor current coilterminalsd. opening the meter and reversingconnections of both potential and current coilterminals

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200. In an Induction type of energy meter,maximum torque is obtained when theparameters (R and X arerespectively the resistance and reactance ofeddycurrent paths in the disc) of rotating disc are[18S03]a. R = 0b. X = 0c. R = Xd. R M X201. In a circuit of single phase inductionenergy meter, the pressure coil lags thevoltage by 880, the errorswhile measuring power in two circuits havingpower factors of unity and 0.5 lagging arerespectively are [19D01]a. -0.061 %, +6.1 %b. +0.061 %, -6.1 %c. -0.061 %, -6.1 %d. -6.1 %, -6.1 %202. The friction error of single phase energymeter can be reduced by [19M01]a. adjusting braking magnetb. shunt magnetc. series magnetd. short circuited loops203. The speed of the meter disc on full loadis kept lowest possible in order to [19M02]a. reduce friction errorb. reduce eddy current lossc. reduce self braking torque

d. reduce copper loss204. In the single phase induction meter, inorder to obtain true value of energy, the shuntmagnet flux should lagbehind the applied voltage by [19M03]a. 900

magnet from the centre of the revolvingdiscd. drilling holes in the disc198. In an energy meter, the movingsystem(or rotating disc) attains the steadyspeed when the [18S01]a. braking torque is zerob. braking torque is equal to operatingtorquec. braking torque is maximumd. braking torque is greater than operatingtorque199. In an Induction type of energy meter,maximum torque is produced when the phaseangle, between the twofluxes is [18S02]a. 00b. 450c. 600d. 900

b. 00c. 450d. 600205. In single phase induction type energymeter, the lag adjustment is done [19M04]a. to make the current coil flux to lag 900behind the applied voltageb. to make the pressure coil flux to lag 900behind the applied voltagec. to bring pressure coil flux in phase with theapplied voltaged. to make the pressure coil flux to lead 900by the applied voltage206. The creeping error in single phaseenergy meter can be minimized by [19S01]a. adjusting braking magnetb. use of short circuited loops on the outerlimbs of the shunt magnetc. drilling two holes in the disc on oppositeside of the spindled. adjusting the shaded band207. 230V, 10A single phase energy metermakes 90 revolutions in 3 minutes at half load,rated voltage andunity power factor. If the meter constant is1800revolutions/kwhthen the error at half fullload will be [19S02]a. 13.04 % slowb. 13.04 % fastc. 15 % slowd. 15 % fast208. Creeping is the phenomenon whichoccurs in [19S03]a. voltmeterb. wattmeterc. energy meterd. ammeter209. Holes are drilled on the opposite sides ofthe disc of an induction type energy meter to[19S04]a. avoid creep on no loadb. balance discc. dissipate the energy due to eddy currentsd. increase the deflecting torque

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210. The adjustment of position of shadingbands, in an energy meter, is affected toprovide [19S05]a. creep compensationb. friction compensationc. frequency compensationd. temperature compensation211. Consider the following statements: aPhantom load is used while testing a highcapacity energy meteri. consists of inductances and capacitances sothat there is no energy loss during testingii. Saves energy during testing because itsvalue changes very rapidly from the highest tothe lowest, thusenabling quick measurementiii. Involves supplying the voltage circuit withthe required voltage and the current circuitfrom a separate lowvoltage supply Of these statements[20D01]a. i, ii, and iii are correctb. i, and ii are correctc. i, and iii are correctd. ii, and iii are correct212. A single phase energy meter operatingon 230V and 5A for 5hours makes 1940revolutions. Meter constantin revolutions /kwh is 400. What is thepower factor of the load? [20M01]a. 1b. 0.843c. 0.7d. 0.6213. The meter constant of a single phaseenergy meter installed in a house is 4800revolutions /kwh, if 5 lampsof 100W each are connected in the circuit.The number of revolutions/minute will be[20M02]a. 40b. 80c. 120d. 160214. The meter constant of a single phase240V induction watt-hour meter is 400revolutions /kwh. The speed ofthe meter disc for a current of 10A at 0.8pflagging will be [20M03]a. 12.8 rpmb. 16.02 rpmc. 18.2 rpmd. 21.1 rpm

215. For testing of energy meters phantomload is used to [20S01]a. isolate the current and voltage circuitsb. use test meters of low current ratingc. reduce power losses during testingd. test meters of large current rating forwhich loads may not be available in thetesting laboratory andreduce power losses during testing216. A single phase energy meter is operatingon 230V, 50Hz supply with a load of 20A for 2hours at unitypower factor. The meter makes 1380revolutionsin that period. The meter constant is [20S02]a. 695 rev/kwhb. 150 rev/kwhc. 0.15rev/kwhd. 1/150 rev/kwh217. A Merz price demand indicator indicates[20S03]a. average maximum demand over aspecified period of timeb. maximum demandc. maximum energy consumptiond. maximum power consumed

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