MCQs on Electrical and Electronics Measurment Part-2

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181)   In electrodynamic instruments, the operating field is produced by

a. Permanent magnet

b. Fixed coil

c. Moving coil

d. All of these

Answer

ANSWER: Fixed coil

182)   A permanent magnet moving coil gives full scale deflection at 40 mV potential difference and 8 mA current. What will be the required series resistance when it is used as voltmeter of range 0 – 200 V? a. 19556 ohm b. 20163 ohm c. 23884 ohm d. 24995 ohm Answer   ANSWER: 24995 ohm 183)   A PMMC instrument gives full scale deflection at 40 mV potential difference and 8 mA current. What will be the required shunt resistance when it is used as ammeter of range 0 – 10 A? a. 0.002 ohm b. 0.003 ohm c. 0.004 ohm d. 0.005 ohm Answer   ANSWER: 0.004 ohm 184)   A moving coil ammeter requires a potential difference of 0.4 V across it for full scale deflection. It has fixed shunt resistance of 0.01 ohm with a coil circuit resistance of R = 1kohm. The value of shunt required to give full scale deflection when the total current is 10 A is equal to a. 0.02 ohm b. 0.04 ohm c. 0.05 ohm d. 0.06 ohm Answer   ANSWER: 0.04 ohm 185)   The voltage multiplication factor of a PMMC instrument is a. Directly proportional to the required series resistance b. Directly proportional to the shunt resistance c. Inversely proportional to the shunt resistance d. Directly proportional to the required series resistance Answer   ANSWER: Directly proportional to the required series resistance 186)   The multiplying factor of a PMMC used as ammeter is a. Directly proportional to the shunt resistance b. Inversely proportional to the shunt resistance c. Inversely proportional to the series resistance d. Directly proportional to the series resistance Answer   ANSWER: Inversely proportional to the shunt resistance 187)   The ratio of maximum current (with shunt) to the full scale deflection current (without current) in a permanent magnet moving coil instrument is known as a. Sensitivity b. Multiplying factor c. Multiplying power d. Both (b) and (c) e. Both (a) and (b) Answer   ANSWER: Both (b) and (c) 188)   If the control springs of PMMC instrument is made up of large moment of inertia, then it can be used as a. Ammeter b. Fluxmeter c. Ballistic galvanometer d. Wattmeter Answer   ANSWER: Ballistic galvanometer 189)   The spring which is used for producing controlling torque in indicating instruments are made up of materials which is / are a. Non - magnetic b. Not subjected to much fatigue c. Low specific resistance and low temperature resistance coefficient d. All of these Answer   ANSWER: All of these 190)   The deflecting torque in a permanent magnet moving coil type instrument is a. Directly proportional to the angle of deflection of moving system b. Directly proportional to the current flowing through it c. Directly proportional to the current flowing through it d. Inversely proportional to the current flowing through it Answer   ANSWER: Directly proportional to the current flowing through it

191)   The restoring torque in a spring controlled indicating instrument is  a. Directly proportional to the angle of deflection of moving system b. Directly proportional to the sine of angle of deflection of moving system c. Inversely proportional to the angle of deflection of moving system d. Directly proportional to the square of the angle of deflection of moving system Answer   ANSWER: Directly proportional to the angle of deflection of moving system

192)   In indicating instruments, the controlling and restoring torque can be obtained by using a. Spring b. Gravity c. Either by spring or by gravity d. Neither by spring nor by gravity Answer   ANSWER: Either by spring or by gravity

193)   The sensitivity drift is also known as scale factor drift defines the amount by which an instruments sensitivity of measurement varies as ambient conditions change. It is measured in units of a. (angular degree / bar) / °C b. °C / (angular degree / bar) c. (angular degree - bar) / °C d. °C / (angular degree - bar) Answer   ANSWER: (angular degree / bar) / °C

194)   The zero drift is measured in units of a. Volts - °C b. Volts / °C c. °C / volts d. (volts)2 / °C Answer   ANSWER: Volts / °C

195)   Zero drift or bias describes the effect  a. Where the zero reading of an instrument is modified by a change in ambient conditions b. Where the zero reading is achieved by increasing sensitivity c. Where the zero reading is achieved by increasing linearity d. None of these Answer   ANSWER: Where the zero reading of an instrument is modified by a change in ambient conditions

196)   The smallest change which can be measured by the transducer of the range of 0 to 150 N force and resolution of 0.1 % of full scale is a. 0.1 N b. 0.15 N c. 0.3 N d. 0.35 N Answer   ANSWER: 0.15 N

197)   If a voltmeter can measure up to 150 V and it has 150 scale divisions where each division can read to ¾ divisions. Then the resolution of the voltmeter is a. 0.5 V b. 0.25 V c. 0.75 V d. 1 V Answer   ANSWER: 0.75 V

198)   Resolution of an instrument is specified as an a. Absolute value b. Percentage of full scale deflection c. Either (a) or (b) d. None of these Answer   ANSWER: Either (a) or (b)

199)   To produce a change in deflection of 1.5 mm of the galvanometer of Wheatstone bridge, a change of 5 Ω in the unknown arm of bridge is required. The sensitivity is a. 0.2 mm / Ω b. 0.3 mm / Ω c. 0.4 mm / Ω d. 0.5 mm / Ω Answer   ANSWER: 0.3 mm / Ω

200)   If one meter A requires 80 mA to give full scale deflection and another meter B requires 60 mA to give full scale deflection, then the a. Meter A is more sensitive b. Both meters are equally sensitive c. Meter B is more sensitive d. Insufficient data Answer   ANSWER: Meter B is more sensitive

201)   The induction type single - phase watt - hour meters uses a. Control spring b. Pointer c. Brake magnet and spindle d. All of these Answer   ANSWER: Brake magnet and spindle

202)   Commutator motor meters are  a. Ampere hour meter b. True watt - hour meter c. Either ampere hour meter or true watt - hour meter d. None of these Answer   ANSWER: Either ampere hour meter or true watt - hour meter

203)   In motor meters, the speed control of the rotating system is done by using  a. Permanent magnet b. Train of gear wheels and dials c. Pinion d. All of these Answer   ANSWER: Permanent magnet

204)   In case of motor meters, the speed of rotation is  a. Directly proportional to the current in case of ampere hour meter and to power in case of watt-hour meter b. Directly proportional to the current in case of ampere hour meter and inversely proportional to the power in case of watt-hour meter c. Inversely proportional to the current in case of ampere hour meter and directly proportional to the power in case of watt-hour meter d. Inversely proportional to the current in case of ampere hour meter and to power in case of watt-hour meter Answer   ANSWER: Directly proportional to the current in case of ampere hour meter and to power in case of watt-hour meter

205)   In potentiometric type DVM, the adjustment of sliding contact is done by  a. A single phase servomotor b. Two phase servomotor c. Three phase servomotor d. All of these Answer   ANSWER: Two phase servomotor

206)   In a ramp type DVM, the multivibrator determines the rate at which the a. Clock pulses are generated b. Measurement cycles are initiated c. It oscillates d. Its amplitude varies Answer   ANSWER: Measurement cycles are initiated

207)   Dipsticks are used for the  a. Pressure measurement b. Flow measurement c. Displacement measurement d. Level measurement Answer   ANSWER: Level measurement

208)   The flow meter which is replacing the differential pressure meters in its applications is  a. Vortex - shedding flow meters b. Electromagnetic flow meters c. Ultrasonic flow meters d. All of these Answer   ANSWER: Vortex - shedding flow meters

209)   Turbine meters are generally preferred for  a. Low viscosity and high flow measurements b. High viscosity and low flow measurements c. High viscosity and high flow measurements d. Low viscosity and low flow measurements Answer   ANSWER: Low viscosity and high flow measurements

210)   If the two input waveforms are of equal amplitude and 90 degree phase difference is applied to the CRO then the Lissajous patterns obtained will be a. Straight line tilted at 45 degree with respect to X - axis b. Circle c. Ellipse d. Vertical straight line Answer   ANSWER: Circle

211)   The Lissajous patterns help in the measurement of a. Phase difference between two sine wave b. Frequency of one waveform if the frequency of other waveform is known c. Both (a) and (b) d. None of these Answer   ANSWER: Both (a) and (b)

212)   In terms of the division on screen, the voltage of the waveform in CRO is  a. Average voltage b. RMS voltage c. Peak to peak voltage d. Maximum voltage Answer   ANSWER: Peak to peak voltage

213)   To avoid wastage of power during calibration in dynamometer type wattmeter  a. Phantom loading is used b. Brake magnet is used c. Spring is used d. Capacitance is used Answer   ANSWER: Phantom loading is used

214)   In a dynamometer type meter, the error due to connections would be minimum if a. Capacitive reactance of pressure coil is greater than its inductive reactance b. Capacitive reactance of pressure coil is equal to its inductive reactance c. Capacitive reactance of pressure coil is lesser than its inductive reactance d. Capacitive reactance of current coil is equal to its inductive reactance Answer   ANSWER: Capacitive reactance of pressure coil is equal to its inductive reactance

215)   A dynamometer type wattmeter reads 200W when its voltage coil is connected across the load whose voltage is 150 V. if the voltage coil has internal resistance of 1800 ohm, then the power taken by the load will be a. 163.8 W b. 171.7 W c. 178.9 W d. 187.5 W Answer  ANSWER: 187.5 W

216)   In wattmeters, errors due to stray fields can be removed by a. Proper instrument construction b. Using brake magnet c. Using shading ring d. Using two separate ac magnets Answer   ANSWER: Proper instrument construction

217)   The Q meter works on the principle of a. Series resonance b. Parallel resonance c. Both (a) and (b) d. Neither series resonance nor parallel resonance Answer   ANSWER: Series resonance

218)   The Maxwell’s Inductance - Capacitance bridge is not suitable for the measurement inductance of coil if the Q factor is  a. Less than 1 b. Between 1 to 10 c. More than 10 d. Both (a) and (c) Answer   ANSWER: Both (a) and (c)

219)   In Maxwell’s Inductance - Capacitance bridge, the frequency ω a. Is directly proportional to the inductance in the balanced equation b. Is inversely proportional to the capacitance in the balanced equation c. Is directly proportional to the product of inductance and capacitance d. Does not appear in the balanced equations Answer   ANSWER: Does not appear in the balanced equations

220)   The given figure shows the Wheatstone bridge method for measurement of unknown resistance (R).  The balanced equation for Wheatstone bridge is given by a. P / R = Q / S b. P / S = Q / R c. P / R = S / Q d. R / p = Q / S Answer   ANSWER: P / R = Q / S

221)   In a Wheatstone bridge method, the bridge is said to be balanced, when the current through the galvanometer is a. 1 A b. 0 A c. Maximum d. Half of the maximum value Answer   ANSWER: 0 A 222)   In Wheatstone bridge method, the instrument used as null detector is a. Ammeter b. Voltmeter c. Galvanometer d. All of these Answer   ANSWER: Galvanometer 223)   In a PMMC instrument, if the control springs are eliminated the instrument can be used for measuring the quantity of electricity passed through the coil. This method is used for a. Ammeter b. Voltmeter c. Fluxmeter d. Ballistic galvanometer Answer   ANSWER: Fluxmeter 224)   A PMMC instrument can be used as ammeter and as voltmeter with the help of a. A low resistance shunt, a low series resistance b. A low resistance shunt, a high series resistance c. A high series resistance, a low resistance shunt d. A low series resistance, a high shunt resistance Answer   ANSWER: A low resistance shunt, a high series resistance 225)   If the control spring of PMMC instrument is replaced by another spring whose spring constant is higher than the previous one, then the damping ratio and natural frequency  a. Increases, decreases b. Increases, increases c. Decreases, decreases d. Decreases, increases Answer   ANSWER: Increases, decreases 226)   When an AC signal is applied across the permanent magnet moving coil voltmeter, then the pointer will a. Not deflect b. Oscillate around zero volt c. Deflect to its maximum d. Oscillate from minimum to maximum value Answer   ANSWER: Oscillate around zero volt 227)   The deflecting torque in a moving coil instrument is a. Directly proportional to the current flowing through it b. Inversely proportional to the current flowing through it c. Inversely proportional to the square of current flowing through it d. Directly proportional to the square of current flowing through it Answer   ANSWER: Directly proportional to the square of current flowing through it 228)   An ac voltage source of 2sint V is connected in series with a dc voltage source of 5 V. If a PMMC instrument is connected in parallel to this combination then the reading of meter will be equal to a. 7 V b. 5 V c. 5.2 V d. 25 V Answer   ANSWER: 5 V 229)   The scale of PMMC type instruments is a. Uniform b. Non - uniform c. Cramped at the lower ends d. Crowded in the middle Answer   ANSWER: Uniform 230)   The coil diameter and length of a PMMC instrument is 1.2 cm and 1.8 cm respectively. The magnetic flux density in air is 0.1 T and the number of turns is 100. If the current of 1.5 mA is flowing through it then the torque produced on the coil is a. 2.58 X 10 -6 N - m b. 2.92 X 10 -6 N - m c. 3.24 X 10 -6 N - m d. 3.92 X 10 -6 N - m Answer   ANSWER: 3.24 X 10 -6 N - m 231)   In the absence of the restoring torque, the pointer a. Will not deflect from its initial position b. Will deflect but would not return to its zero position on removing current c. Will deflect and return to its zero position on removing current d. Will swing from minimum to maximum position Answer   ANSWER: Will deflect but would not return to its zero position on removing current 232)   If the deflection torques on moving system increases then the controlling torque  a. Increases b. Decreases c. Remains same d. None of these Answer   ANSWER: Increases 233)   In an instrument torque / weight ratio is known as a. Sensitivity b. Accuracy c. Linearity d. Fidelity Answer   ANSWER: Sensitivity 234)   A speedometer typically has a threshold of about 15 km/hr. If the car starts from rest and accelerates, the speedometer will a. Starts reading from the moment the car starts b. Starts reading when the speed reaches 15 km/hr c. Starts reading when the speed reaches 30 km/hr d. None of these Answer   ANSWER: Starts reading when the speed reaches 15 km/hr 235)   The sensitivity of a measurement is a measure of  a. Change in instrument output when the quantity being measured changes by a given amount b. Closeness of output readings for the same input when there are changes in the method of measurement c. Ratio of output to the input d. Closeness of output reading of instrument to the true value Answer   ANSWER: Change in instrument output when the quantity being measured changes by a given amount 236)   The output reading of an instrument is  a. Linearly proportional to the quantity being measured b. Inversely proportional to the quantity being measured c. Exponentially proportional to the quantity being measured d. Not related to the quantity being measured Answer   ANSWER: Linearly proportional to the quantity being measured 237)   Four observers recorded a set of current measurement as: 125.09 mA, 125.21 mA, 125.05 mA, 125.14 mA. The range or span of error will be a. ± 0.02 mA b. ± 0.06 mA c. ± 0.08 mA d. ± 1.02 mA Answer   ANSWER: ± 0.08 mA 238)   A voltmeter of 0 to 250 V has an error of ± 1 % of full scale deflection. If the true voltage of voltmeter is 25 V then the range of its reading is a. 22.5 V – 27.5 V b. 27.5 V – 29.5 V c. 24 V – 26 V d. 25.5 V – 26.5 V Answer   ANSWER: 22.5 V – 27.5 V 239)   Range or span of an instrument defines the  a. Minimum value of quantity that the instrument is designed to measure b. Maximum value of quantity that the instrument is designed to measure c. Both minimum and maximum value of quantity that the instrument is designed to measure d. None of these Answer   ANSWER: Both minimum and maximum value of quantity that the instrument is designed to measure 240)   For an instrument the degree of repeatability or reproducibility in measurements is an alternative way of expressing its a. Precision b. Accuracy c. Sensitivity d. Linearity Answer   ANSWER: Precision 241)   Which among the following is not a type of digital voltmeters? a. Ramp type b. Integrating c. Potentiometric type d. None of these Answer   ANSWER: None of these 242)   The measurement range of digital voltmeter is  a. ± 1V to ± 1MV b. ± 1V to ± 1kV c. ± 1kV to ± 1MV d. ± 100 kV to ± 100MV Answer   ANSWER: ± 1V to ± 1MV 243)   In electronic voltmeter, the range of input voltages can be extended by using a. Functional switch b. Input attenuator c. Rectifier d. Balanced bridge dc amplifier Answer   ANSWER: Input attenuator 244)   Example for positive displacement meter is a. Variable area flow meter b. Turbine meters c. Rotary piston meter d. Venturi Answer   ANSWER: Rotary piston meter 245)   The instrument which is not suitable for the application in automatic control scheme a. Rotameters b. Pitot static tube c. Rotary piston meter d. Orifice plate Answer   ANSWER: Rotameters 246)   For the measurement of flow the cheapest device is a. Venturi b. Dall flow tube c. Flow nozzle d. Pitot static tube Answer   ANSWER: Flow nozzle 247)   The device which is used for making temporary measurements of flow is a. Venturi b. Dull flow tube c. Orifice plate d. Pitot static tube Answer   ANSWER: Orifice plate 248)   If the bombardment of electrons ceases i.e. when the signal becomes zero then the light emitted by the screen will a. Disappear immediately b. Persist for some time then it will disappear c. Will not disappear at all d. None of these Answer   ANSWER: Persist for some time then it will disappear 249)   The light emitted by the zinc silicate coated fluorescent screen of cathode ray tube is usually of  a. Green colour b. Yellow colour c. Blue colour d. White colour Answer   ANSWER: Green colour 250)   Which part is called as heart of CRO? a. CRT b. Sweep generator c. Trigger circuit d. Amplifier Answer   ANSWER: CRT 251)   Commutator type meters can be used for a. AC supply b. DC supply c. Both AC and DC supply d. None of these Answer   ANSWER: Both AC and DC supply 252)   An electrolytic ampere hour meter can be converted into watt - hour meter by a. Multiplying them by the voltage of the circuits in which it is used b. Multiplying them by the current of the circuits in which it is used c. Multiplying them by the power of the circuits in which it is used d. Cannot be converted Answer   ANSWER: Multiplying them by the voltage of the circuits in which it is used 253)   In some wattmeters, a small capacitor is connected in parallel with the series resistor for a. Reducing error due to inductance of the series resistor b. Obtaining non inductive voltage coil current c. Making resultant reactance capacitive d. All of these e. None of these Answer   ANSWER: All of these 254)   What will happen if the current coil & potential coil of dynamometer type wattmeter is interchanged? a. Potential coil will get damaged b. Current coil will get damaged c. Both current coil and potential coil will get damaged d. Neither potential coil nor current coil will get damaged Answer   ANSWER: Current coil will get damaged 255)   Due to the inductance in the pressure coil of dynamometer type wattmeter, the reading will be a. High for both leading and lagging power factors b. Low for both leading and lagging power factors c. High for lagging power factor and low for leading power factor d. Low for lagging power factor and high for leading power factor Answer   ANSWER: High for lagging power factor and low for leading power factor 256)   The dynamometer wattmeters are a. More accurate on DC supply b. More accurate on AC supply c. Equally accurate on both AC and DC supply d. None of these Answer   ANSWER: Equally accurate on both AC and DC supply 257)   Under balanced condition, the current flowing through the detector is equal to a. 1 A b. 0 A c. Sum of the currents flowing in the adjacent arms d. Difference between the current flowing in the adjacent arms Answer   ANSWER: 0 A 258)   The AC Bridge used for the measurement of inductance is / are a. Maxwell’s inductance bridge b. Hay’s bridge c. Anderson’s bridge, Owen’s bridge d. All of these e. None of these Answer   ANSWER: All of these 259)   The vibration galvanometer used as detector, it responds  a. Only to the fundamental frequency b. Only to the harmonics frequency c. Both (a) and (b) d. Does not respond to any frequency Answer   ANSWER: Only to the fundamental frequency 260)   A null type of bridge with DC excitation is commonly known as a. Wheatstone bridge b. Anderson bridge c. Wien bridge d. Schering bridge Answer   ANSWER: Wheatstone bridge 261)   The high resistances are found in a. Insulation resistance of cables and wires b. Resistance of shunt field winding and the multipliers c. Resistance of armature windings of electrical machine d. Resistance of series field winding of a dc machine Answer   ANSWER: Insulation resistance of cables and wires 262)   The accuracy in a bridge measurement depends on a. Sensitivity of detector b. Applied voltage c. Accuracy of indicator d. Both (a) and (b) Answer   ANSWER: Both (a) and (b) 263)   In a permanent magnet moving coil instrument, the deflecting torque is  a. Directly proportional to both number of turns and flux density b. Directly proportional to the number of turns and inversely proportional to the flux density c. Inversely proportional to the number of turns and directly proportional to the flux density d. Inversely proportional to both number of turns and flux density Answer   ANSWER: Directly proportional to both number of turns and flux density 264)   A current of 2 + 3sinωt A is passed through a moving iron instrument and through a meter respectively. The readings of the two meters are a. 2 A, 2 A b. 2 A, 2.9 A c. 2.9 A, 2.9 A d. 2.9 A, 2 A Answer   ANSWER: 2.9 A, 2 A 265)   For extending the range of 0 - 150 V to 0 - 500 V in a 10000 Ω / V meter, the value of series resistance required is equal to a. 3 M Ω b. 3.5 M Ω c. 4 M Ω d. 4.5 M Ω Answer   ANSWER: 3.5 M Ω 266)   For a moving iron ammeter, the change of inductance is 3 μ H / degree and its spring constant is 4 X10 -7 N – m / degree. If the maximum deflection of the pointer is 90 degree, then the corresponding current in the coil be a. 3.89 A b. 4.05 A c. 4.89 A d. 5 A Answer   ANSWER: 4.89 A 267)   A moving iron instrument is used as an ammeter. Its range can be extended by using a. Suitable shunt across its terminal b. A high non - inductive resistance c. Either (a) or (b) d. Neither (a) nor (b) Answer   ANSWER: Suitable shunt across its terminal 268)   What will a moving iron ammeter read if a rectangular waveform current with peak value of 120 mA is passed through it? a. 120 mA b. 84.8 mA c. 169.7 mA d. 60 mA Answer   ANSWER: 120 mA 269)   A repulsion type moving iron instrument when used with AC circuits, the deflecting torque is  a. Directly proportional to the rms current b. Directly proportional to the square of rms current c. Directly proportional to the peak current d. Directly proportional to the square of the peak current Answer   ANSWER: Directly proportional to the square of rms current 270)   A spring controlled moving iron voltmeter with full scale deflection of 150 V draws a current of 2 mA. What will be the meter reading if it draws a current of 1 mA? a. 25.5 V b. 27.5 V c. 35.5 V d. 37.5 V Answer   ANSWER: 37.5 V 271)   The moving system in the indicating instruments is subjected to a. Deflecting torque b. Controlling torque c. Damping torque d. All the above e. None of the above Answer   ANSWER: All the above 272)   Integrating instruments is the subdivision of the secondary instruments. The example for integrating instruments is a. Ampere - hour meters b. Watt - hour meters c. Wattmeters d. Ampere - hour and watt - hour meters Answer   ANSWER: Ampere - hour and watt - hour meters 273)   Choose the correct option. I. Repeatability means the closeness of output readings when the same input is applied repetitively over a short period of time, with the same measurement conditions and same instruments. II. Reproducibility means the closeness of output readings for the same input when there are changes in the method of measurement and conditions of measurement a. Both I and II are correct b. Only I is correct c. Only II is correct d. Both are incorrect Answer   ANSWER: Both I and II are correct 274)   Low accuracy measurements from a high precision instrument are normally caused by  a. Bias in the measurement b. Human errors c. Instrumental defect d. Low temperature Answer   ANSWER: Bias in the measurement 275)   An instrument with high precision implies a. High accuracy b. Low accuracy c. Does not imply anything about measurement accuracy d. None of these Answer   ANSWER: Does not imply anything about measurement accuracy 276)   Precision of an instrument is defined as  a. Closeness of output to the true value b. Change in output for every change in input c. Degree of freedom from random errors d. Both (a) and (b) Answer   ANSWER: Degree of freedom from random errors 277)   A voltmeter connected across a resistor gives a value of 65 V but the expected value of resistor was 68 V. Then the absolute error and the relative accuracy of the measurement will be a. 3.2%, 96.8% b. 3.8%, 96.2% c. 4%, 96% d. 4.4%, 95.59% Answer   ANSWER: 4.4%, 95.59% 278)   An instrument with a range of 0 -10 bar is used for measuring pressure. If the expected value of reading is between 0 and 1 bar then the instrument will give a. More accurate readings than the instrument with range of 0 - 5 bar b. Less accurate readings than the instrument with range of 0 - 5 bar c. Accuracy of reading will be same for both the instruments with range of 0 - 10 bar and 0 - 5 bar d. None of these Answer   ANSWER: Less accurate readings than the instrument with range of 0 - 5 bar 279)   If a pressure gauge of range 0 - 10 bar has a quoted inaccuracy of ±1.0 % of full scale reading, then it means a. Minimum expected error in any reading is 0.1 bar b. Maximum expected error in any reading is 0.1 bar c. Maximum expected error in any reading is 1 bar d. Minimum expected error in any reading is 1 bar Answer   ANSWER: Maximum expected error in any reading is 0.1 bar 280)   Accuracy of a measuring instrument indicates the a. Closeness of the output reading to the true value b. Ratio of output value to the input value c. Change in output with each change in input d. Degree of freedom from random errors Answer   ANSWER: Closeness of the output reading to the true value 281)   An RMS reading voltmeter can accurately measure voltages of a. Sine waveforms b. Square waveforms c. Saw tooth waveforms d. All of these e. None of these Answer   ANSWER: All of these 282)   Electronic voltmeters can be designed to measure  a. Only very small voltages b. Only very high voltages c. Both very small and very high voltages d. None of these Answer   ANSWER: Both very small and very high voltages 283)   To increase the current sensitivity below 10 mV, electronic instrument uses a. Amplifiers b. Modulator c. Transducer d. Oscillator Answer   ANSWER: Amplifiers 284)   The devices used for flow obstruction is / are a. Orifice plate b. Venturi tube c. Flow nozzle and dall flow tube d. All of these Answer   ANSWER: All of these 285)   For the measurement of flow rate of liquid, the method used is a. Conveyor - based methods b. Bourdon tube c. Coriolis method d. Thermal mass flow measurement Answer   ANSWER: Coriolis method 286)   Conveyor - based method is used for the measurement of the flow of a. Solids b. Liquid c. Gas d. All of these Answer   ANSWER: Solids 287)   The rate at which fluid flows through a closed pipe can be determined by a. Determining the mass flow rate b. Determining the volume flow rate c. Either (a) or (b) d. None of these Answer   ANSWER: Either (a) or (b) 288)   The sweep generator of a CRO is used to produce a. Sinusoidal voltage for the horizontal deflection of electron beam b. Saw tooth voltage for the vertical deflection of electron beam c. Sinusoidal voltage for the vertical deflection of electron beam d. Saw tooth voltage for the horizontal deflection of electron beam Answer   ANSWER: Saw tooth voltage for the horizontal deflection of electron beam 289)   Principally CRO is a a. Ammeter b. Voltmeter c. Wattmeter d. Watt - hour meter Answer   ANSWER: Voltmeter 290)   CRO gives the visual representation of time varying signals. The display of the signal is a. One dimensional b. Two dimensional c. Three dimensional d. Four dimensional Answer   ANSWER: Two dimensional 291)   The electrolytic energy meters are essentially  a. A true watt - hour meter b. An ampere hour meter c. Either watt - hour or ampere hour meter d. Neither watt - hour nor ampere hour meter Answer   ANSWER: An ampere hour meter 292)   The instrument which works only with DC is a. Electrolytic motor b. Mercury motor c. Induction motor d. Both (a) and (b) e. None of these Answer   ANSWER: Both (a) and (b) 293)   In a dynamometer type wattmeter, the pressure coil connected across the load terminal is a. Highly inductive b. Highly capacitive c. Highly resistive d. Non inductive Answer   ANSWER: Highly resistive 294)   In standard wattmeters, the error caused by the voltage coil is overcome by a. Connecting a high inductive resistance in series to the voltage coil b. Connecting a high inductive resistance in parallel to the voltage coil c. Connecting a compensating winding in series to the voltage coil d. Connecting a compensating winding in parallel to the voltage coil Answer   ANSWER: Connecting a compensating winding in series to the voltage coil 295)   The scale of dynamometer wattmeter is  a. Approximately uniform b. Cramped at the middle c. Cramped at the end points d. Crowded in the first half Answer   ANSWER: Approximately uniform 296)   In case of DC supply and AC supply, the torque produced is  a. Directly proportional to power, inversely power to power b. Directly proportional to power, directly proportional to power c. Inversely proportional to power, inversely proportional to power d. Inversely proportional to power, directly proportional to power Answer   297)   The vibration galvanometers are sensitive to power for frequency range of a. 200 Hz and below b. 200 Hz to about 4 kHz c. 4 kHz and above d. Any frequency Answer   ANSWER: 200 Hz and below 298)   The commonly used detector(s) in AC bridges is / are a. Head phones b. Vibration galvanometers c. Tuned amplifiers, head phones d. Head phones, tuned amplifiers, vibration galvanometers Answer   ANSWER: Head phones, tuned amplifiers, vibration galvanometers 299)   AC bridges are used for the measurement of a. Resistances b. Resistances and Inductances c. Inductances and capacitances d. Resistances, inductances and capacitances Answer   ANSWER: Inductances and capacitances 300)   The example of low resistance is / are a. Resistance of armature windings of electrical machine b. Resistance of series field winding of a dc machine c. Resistances of shunts and lead wires d. All of these Answer   ANSWER: All of these 301)   Low resistance is the resistance of the order of a. 1 ohm and less than 1 ohm b. 1 ohm to 1 mega ohm c. More than one ohm d. None of these Answer   ANSWER: 1 ohm and less than 1 ohm 302)   Bridge circuits are used for the measurement of a. Resistance b. Inductance c. Capacitance d. All of these Answer   ANSWER: All of these 303)   In the given options, the secondary fundamental unit is a. Length b. Luminous intensity c. Plane angle d. Time Answer   ANSWER: Luminous intensity 304)   If the direction of current through the coil is upward, then the iron disc will be magnetized in such a way that it is a. Pushed outwards b. Pushed upwards c. Pushed downwards d. Pulled inwards Answer   ANSWER: Pulled inwards 305)   If a moving iron instrument is to be used as ammeter then the coil has a. Fewer number of turns of thin wire b. Fewer number of turns of thick wire c. Larger number of turns of thin wire d. Larger number of turns of thick wire Answer   ANSWER: Fewer number of turns of thick wire 306)   To convert a 2 mA meter with internal resistance of 120 ohm into an ammeter of range 0 – 200 mA, the value of shunt resistance required is  a. 1.121 ohm b. 1.212 ohm c. 1.312 ohm d. 1.414 ohm Answer   ANSWER: 1.212 ohm 307)   In a hot wire instrument, readings are a. Dependent on frequency b. Dependent on waveform c. Dependent on both frequency and waveform d. Independent of both frequency and waveform Answer   ANSWER: Independent of both frequency and waveform 308)   In a hot wire ammeter the current flowing through the resistance of 10 Ω is given by I = 3 + 2 sin 300 t A The measured value of current will be a. 2.98 A b. 3.31 A c. 3.62 A d. 4.01 A Answer   ANSWER: 3.31 A 309)   The instrument which can be used only with the A.C. supply is / are a. Induction type b. Electrostatic type c. Electrodynamometer type d. All of these Answer   ANSWER: Induction type 310)   The instrument which can be used only with the D.C. supply is a. PMMC instrument b. Electrodynamometer instrument c. Hot - wire instrument d. Split phase induction type instrument Answer   ANSWER: PMMC instrument 311)   The electrostatic effect is utilized for a. Ammeters b. Voltmeters c. D.C. ampere - hour meters d. Wattmeters Answer   ANSWER: Voltmeters 312)   The electromagnetic effect is generally utilized for a. Ammeters b. Voltmeters c. Wattmeters and watt - hour meters d. All of these Answer   ANSWER: All of these 313)   To read and record a measurement, the indicating type instruments a. Always requires human intervention b. Does not requires human intervention c. Requires human intervention only when the instrument consists of a rotating pointer moving against a scale d. Requires human intervention only when the instrument consists of a rotating scale moving against a pointer Answer   ANSWER: Always requires human intervention 314)   The microcomputer performs its computations in a. Analogue form b. Digital form c. Either analogue form or digital form depending on their applications d. None of these Answer   ANSWER: Digital form 315)   The output of an analogue instrument varies a. Continuously and can have an infinite number of values within its range of instruments b. In discrete steps and can have an infinite number of values within its range of instruments c. Continuously and can have an finite number of values within its range of instruments d. In discrete steps and can have an infinite number of values within its range of instruments Answer   ANSWER: Continuously and can have an infinite number of values within its range of instruments 316)   In terms of usage, deflection type instruments are a. More convenient than null type instrument b. Less convenient than null type instruments c. Both are equally convenient d. None of these Answer   ANSWER: More convenient than null type instrument 317)   The accuracy of the deflection type instruments and of the null type instruments depends on a. Linearity, calibration of spring b. Calibration of spring, linearity and calibration of weights c. Linearity and calibration of spring, calibration of weights d. Both depends on calibration of weight Answer   ANSWER: Linearity and calibration of spring, calibration of weights 318)   In deadweight gauge, weights are added on the top of piston until the piston reaches a datum level. The datum level is known as a. Null point, where the downward force balances the fluid pressure b. Lowest point of the container c. Highest level of fluid in the container d. None of these Answer   ANSWER: Null point, where the downward force balances the fluid pressure 319)   Considering cost of instruments, which is better choice, active or passive? a. Active instruments b. Passive instruments c. Cost of both active and passive instruments are approximately same d. None of these Answer   ANSWER: Passive instruments 320)   Instruments are subdivided into active and passive based on whether the output of instrument is produced by the quantity being measured simply changes the magnitude of some external power source. The pressure measuring device and the float - type petrol tank level indicator are example of a. Active instruments b. Passive instruments c. Former is active instrument and later is passive instrument d. Former is passive instrument and later is active instrument Answer   ANSWER: Former is passive instrument and later is active instrument