MCQs on Electrical and Electronics Measurment Part-1

1)   The full range of audibility in audio frequency oscillator is                       HOME a. 0 to 20 Hz b. 20 Hz to 2 kHz c. 20 Hz to 20 kHz d. 20 Hz to 20 MHz Answer   ANSWER: 20 Hz to 20 kHz

2)   A liquid crystal display requires a. An AC drive b. A DC drive c. Both AC and DC drive d. None of these Answer   ANSWER: An AC drive

3)   The detectors used in optical sensors is a. Photodiodes b. Phototransistors c. Laser d. Only (a) and (b) e. All the above Answer     ANSWER: Only (a) and (b)

4)   Optical sensors used for the displacement measurement works on the principal that a. Intensity of light increases with distance b. Intensity of light decreases with distance c. Intensity of light remains constant with distance d. Intensity of light increases with time Answer   ANSWER: Intensity of light decreases with distance

5)   Capacitance sensor can measure very small displacement. It can be formed by varying a. Separation b. Area c. Permittivity d. Either (a) or (b) or (c) Answer   ANSWER: Either (a) or (b) or (c)

6)   The ionization gauge an instrument used for the measurement of  a. Very low pressure b. Medium pressure c. High pressure d. Very high pressure Answer   ANSWER: Very low pressure

7)   Dead weight gauge is used for the measurement of pressure of a. About 1000 bar b. About 2000 bar c. About 5000 bar d. About 7000 bar Answer   ANSWER: About 7000 bar

8)   Bourdon tube is used for the measurement of gauge pressure of a. Gas b. Liquid fluid c. Solid d. Only (a) and (b) e. All the above Answer   ANSWER: Only (a) and (b)

9)   The resistances of potential transformer winding is minimized by using a. Thick conductors and small length of turns b. Thin conductors and small length of turns c. Thin conductors and large length of turns d. Thick conductors and large length of turns Answer   ANSWER: Thick conductors and small length of turns

10)   The nominal ratio for a current transformer is given by a. (rated primary winding current)/(rated secondary winding current) b. (number of turns in the primary winding)/(number of turns in the secondary winding ) c. (number of turns in the secondary winding)/(number of turns in the primary winding ) d. (rated secondary winding current)/(rated primary winding current) Answer   ANSWER: (rated primary winding current)/(rated secondary winding current)

11)   Moving iron power factor meter are suitable for 3 phase balanced circuits. It consists of a. One control spring b. Two control spring c. Three control spring d. No control spring Answer   ANSWER: No control spring

12)   If the frequency of electrodynamic power factor meter is doubled then its reading will become a. Twice of the original reading b. Half of the original reading c. Four times of the original reading d. Remains unaffected Answer   ANSWER: Remains unaffected

13)   A moving iron frequency meter consists of a. Two inductive circuits connected in parallel b. One inductive and one non inductive circuit connected in parallel c. Two non inductive circuits connected in parallel d. One inductive and one non inductive circuit connected in series Answer   ANSWER: One inductive and one non inductive circuit connected in parallel

14)   The electrodynamic frequency meters have a. Linear scale and their readings does not depends on voltage b. Linear scale and their readings depends on voltage c. Non linear scale and their readings does not depends on voltage d. Non linear scale and their readings depends on voltage Answer   ANSWER: Linear scale and their readings does not depends on voltage

15)   The earth resistance can be measured by  a. Fall of potential method b. Using an earth tester c. Ducter ohmmeter method d. Only (a) and (b) e. All the above Answer   ANSWER: Only (a) and (b)

16)   Electrical equipments are generally earthed through an electrode to avoid shocks when someone touches the body of the equipment. The earth resistance is effected by a. Depth of electrodes buried in the soil b. Shape and material of earth electrodes c. Specific resistance of the soil surrounding the electrode d. All of these e. None of these Answer   ANSWER: All of these

17)   When a voltmeter - ammeter method is applied for the measurement of resistance, the voltmeter reads a value of 8.28 V and the ammeter reading is 4.14 mA. Then the value of the resistance will be a. 2 kΩ b. 2.0 kΩ c. 2.00 kΩ d. 2.000 kΩ Answer   ANSWER: 2.00 kΩ

18)   At 2 MHz, the resonance is obtained with a resonating capacitance value of 12 pF and at 400 kHz, the resonance is obtained with resonating capacitance value of 320 pF. Then the self capacitance of the coil is a. 0.62 pF b. 0.83 pF c. 1.2 pF d. 1.5 pF Answer   ANSWER: 0.62 pF

19)   In AC bridges, the Wagner earth devices are used to a. Remove all the earth capacitances from the bridge circuit b. Remove harmonics c. Reduce error caused by stray electric field d. All of these Answer   ANSWER: All of these

20)   Shielding of the capacitor is done to a. Make the value of capacitor definite b. Balance the bridge without any problem c. Both (a) and (b) d. None of these Answer   ANSWER: Both (a) and (b)

21)   The indicating instruments with linear scale is a. PMMC b. Electrostatic instrument c. Dynamometer instrument d. Thermocouple instrument Answer   ANSWER: PMMC

22)   The resistance potential divider method and capacitance potential divider method is used for a. Both AC and DC b. Former method can be used for both AC and DC and the later method can be used only for AC c. Former method can be used for AC only and the later method can be used for both AC and DC d. Former method can be used for DC only and the later method can be used only for AC Answer   ANSWER: Former method can be used for both AC and DC and the later method can be used only for AC

23)   The range of electrostatic voltmeter can be extended by using  a. Resistance potential divider method b. Capacitance potential divider method c. Both (a) and (b) d. None of these Answer   ANSWER: Both (a) and (b)

24)   The multiplying factor of electrostatic voltmeters is given by a. ( C + C v ) / C b. ( C + C v ) / C v c. C / ( C + C v ) d. C v / ( C + C v ) Answer   ANSWER: ( C + C v ) / C

25)   In electrostatic instruments iron is not used for construction. These instruments are a. Free from hysteresis and eddy current losses b. Free from temperature errors c. Dependent on temperature errors d. Both (a) and (b) e. None of the above Answer   ANSWER: Both (a) and (b)

26)   If an electrostatic voltmeter is used on AC circuit and has non uniform waves, then it will read a. Average values b. RMS values c. Peak values d. All of these Answer   ANSWER: RMS values

27)   Electrostatic voltmeter instruments are suitable for  a. AC work only b. DC work only c. Both AC and DC work d. None of these Answer   ANSWER: Both AC and DC work

28)   A Kelvin’s multicellular voltmeter has a torsion head and a coach spring for a. Protection against accidental fraction of suspension due to vibration b. For zero adjustment c. Torsion head for zero adjustment and coach spring for Protection against accidental fraction of suspension due to vibration d. Torsion head for Protection against accidental fraction of suspension due to vibration and coach spring for zero adjustment Answer   ANSWER: Torsion head for zero adjustment and coach spring for Protection against accidental fraction of suspension due to vibration

29)   In electrostatic voltmeters, the principle of their operation is the force of attraction between electric charges on neighboring plates between which potential difference is maintained. The attracted - disc type electrostatic instruments are used for the measurement of  a. Very low voltages b. Low voltages c. High voltages d. Very high voltages Answer   ANSWER: Very high voltages

30)   Electrostatic instruments are generally used as  a. Voltmeters b. Ammeters c. Wattmeters d. Watt-hour meters Answer   ANSWER: Voltmeters

31)   Due to overdamping, the instrument will become a. Slow b. Lethargic c. Fast d. Both (a) and (b) Answer   ANSWER: Both (a) and (b)

32)   If the degree of damping of an instrument should be adjusted to a value which is sufficient to enable the pointer to rise quickly to its deflected position without overshooting is called as a. Overdamped b. Dead beat c. Underdamped d. None of these Answer   ANSWER: Dead beat

33)   In a Wheatstone bridge, the formula for finding unknown resistance (R2) is given by R2 = ( R2 R3 ) / R1 Where, R1 = 150Ω ± 0.1% R2 = 250Ω ± 0.1% R3 = 300Ω ± 0.1% a. R2 = 250Ω ± 0.1% b. R2 = 300Ω ± 0.3% c. R2 = 750Ω ± 0.3% d. R2 = 500Ω ± 0.3% Answer   ANSWER: R2 = 500Ω ± 0.3%

34)   While measuring resistance by the voltmeter - ammeter method, the maximum possible percentage error in the voltmeter and ammeter are ± 1.8% and ± 1.2% respectively. Then the maximum possible percentage error in the value of resistance will be a. ± 3% b. ± 4% c. ± 4.2% d. ± 4.8% Answer   ANSWER: ± 3%

35)   If the resistance in a circuit is given by 80 Ω ± 0.2% and the current flowing through it is 5A ± 0.1%, then the uncertainty in the power will be a. ± 0.2 % b. ± 0.4 % c. ± 0.6 % d. ± 0.8 % Answer   ANSWER: ± 0.4 %

36)   If the two voltage measurements are V1 = 150 ± 2% and V2 = 100 ± 4% respectively. Then the maximum percentage error in the sum of two voltage measurements is a. ± 2.4 % b. ± 2.6 % c. ± 2.8 % d. ± 3.4 % Answer   ANSWER: ± 2.8 %

37)   When a 100 V moving iron voltmeter is of accuracy class 1 - 0 is used in a circuit, it reads 50 V. Then the maximum possible percentage error in the reading is a. 1 % b. 2 % c. 2.5 % d. 3 % Answer   ANSWER: 2 %

38)   In a measurement system, a. A single measurement components may have both random errors and systematic errors b. A measurement system consists of several components with each component having separate errors c. Both the statement (a) & (b) are true d. Neither statement (a) nor statement (b) is true Answer   ANSWER: Both the statement (a) & (b) are true

39)   The error between mean of finite data set and mean of infinite data set is known as  a. True error of the mean b. Standard error of the mean c. Finite error d. Infinite error Answer   ANSWER: Standard error of the mean

40)   If the quantity to be measured remains constant during the process of taking the repeated measurements then the random errors can be eliminated by a. Calculating the mean of the number of repeated measurements b. Calculating the median of the number of repeated measurements c. Calculating the sum of the numbers of repeated measurements d. Either (a) or (b) Answer   ANSWER: Either (a) or (b)

41)   In liquid crystal displays, the liquid crystal exhibits properties of a. Liquid b. Solids c. Gases d. Both (a) and (b) Answer   ANSWER: Both (a) and (b)

42)   In light emitting diode, the available light emitting region is  a. Less than 2.5 mm b. From 2.5 to 25 mm c. Greater than 25 mm d. Greater than 50 mm Answer   ANSWER: From 2.5 to 25 mm

43)   Resolver works on the principal of mutual inductance variation. It is mainly used for the measurement of a. Linear displacement b. Non - linear displacement c. Rotary motion d. All of these Answer   ANSWER: Rotary motion

44)   In rotary variable differential transformer, the mutual inductance between the primary and secondary coils varies a. Linearly with the angular displacement b. Non - linearly with the angular displacement c. Linearly with the linear displacement d. Non - linearly with the linear displacement Answer   ANSWER: Linearly with the angular displacement

45)   LVDT which is an instrument for the measurement of displacement, works on the principal of  a. Linear inductance b. Non - linear inductance c. Mutual inductance d. Linear capacitance Answer   ANSWER: Mutual inductance

46)   The instruments used for the measurement of pressure is / are a. Bellows b. Diaphragms c. Fiber optic pressure sensors d. All of these e. None of the above Answer   ANSWER: All of these

47)   A capacitive pressure sensor has a typical measurement uncertainty of a. ± 0.2% b. ± 0.4% c. ± 0.1% d. ± 0.8% Answer   ANSWER: ± 0.2%

48)   If the displacement is measured with strain gauge then the number of strain gauge normally required are a. One b. Two c. Three d. Four Answer   ANSWER: Four

49)   If an instrument transformer is used to extend the ranges of AC instrument, then its reading will depend on a. R b. L c. C d. All of these e. None of these Answer   ANSWER: None of these

50)   The potential transformers are used to measure large voltage using a. High range voltmeter b. Low range voltmeter c. High range ammeter d. Low range ammeter Answer   ANSWER: Low range voltmeter

51)   The meter of a vibrating reed frequency meter depends for its indications on the a. Electrical resonance of thin flat steel reeds b. Mechanical resonance of thin flat steel reeds c. Mechanical resonance of thick flat steel reeds d. Electrical resonance of thick flat steel reeds Answer   ANSWER: Mechanical resonance of thin flat steel reeds

52)   Vibration galvanometer are generally used  a. For measuring electric charges b. As null - point detectors in ac bridges c. As null - point detectors in dc bridges d. For measuring power Answer   ANSWER: As null - point detectors in ac bridges

53)   Ballistic galvanometer are principally used for the measurement of  a. Current b. Voltage c. Power d. Electric charges Answer   ANSWER: Electric charges

54)   The two wattmeters used for the measurement of power input read 50 kW each. What will be the readings of the two wattmeters if the power factor is changed to 0.8 leading keeping the total input power same? a. 28.35W, 71.65W b. 31.25W, 73.71W c. 33.33W, 73.33W d. 38.35W, 75.5W Answer   ANSWER: 28.35W, 71.65W

55)   If a capacitor is connected across a portion of resistance of multiplier of the wattmeter then the pressure coil of the circuit becomes a. Inductive b. Non inductive c. Capacitive d. Non capacitive Answer   ANSWER: Non inductive

56)   For the measurement of unknown inductance in terms of known capacitance, the suitable ac bridges are a. Maxwell and Schering bridge b. Maxwell and Wien’s bridge c. Maxwell and Hay’s bridge d. Hay’s and Wien’s bridge Answer   ANSWER: Maxwell and Hay’s bridge

57)   The Wien’s bridges is suitable for the measurement of frequency of the range of a. Less than 100 Hz b. 100 Hz to 100 kHz c. 1 kHz to 100 MHz d. More than 100 MHz Answer   ANSWER: 100 Hz to 100 kHz

58)   In a slide wire potentiometer, for a voltage source of 1.012 V the jockey is kept at 101.2 cm. If the potentiometer has 20 wires of 1 m each and the resistance of wires is 800 ohm, then the value of the working current is a. 15 mA b. 20 mA c. 25 mA d. 27 mA Answer   ANSWER: 25 mA

59)   For the measurement of low resistances from few ohms down to one micro ohm, which of the following instrument is not suitable? a. Potentiometer method b. Ammeter – voltmeter method c. Ohmmeter d. Kelvin double bridge method Answer   ANSWER: Ohmmeter

60)   For the measurement of low resistances, Kelvin’s double bridge has high accuracy because a. It has two set of ratio arms which eliminates effect of resistance of connecting lead b. It has a null indicating galvanometer c. It has two null indicator d. It has four sets of ratio arms which eliminates the effect of resistance of connecting lead Answer   ANSWER: It has two set of ratio arms which eliminates effect of resistance of connecting lead

61)   Swamping resistance is a resistance made up of  a. Alloy of manganin and copper b. Alloy of aluminium and copper c. Alloy of nickel and cobalt d. Alloy of manganin and aluminium Answer   ANSWER: Alloy of manganin and copper

62)   In a moving coil of a meter swamping resistance is added to  a. Reduce the frequency error b. Reduce the temperature error c. Reduce the power consumption d. All of these Answer   ANSWER: Reduce the temperature error

63)   Which among the following is not true about the induction instruments? a. It can be used for ac measurements only b. Damping is very efficient in case of induction instruments c. Compensation for frequency temperature is not required d. Cost is relatively high Answer   ANSWER: Compensation for frequency temperature is not required

64)   The temperature errors in induction instruments can be compensated by  a. Hunting in both ammeters and voltmeters b. Combination of shunt and swamping resistance in both ammeters and voltmeters c. Hunting in case of ammeters and Combination of shunt and swamping resistance in case of voltmeters d. Combination of shunt and swamping resistance in case of ammeters and hunting in case of voltmeters Answer   ANSWER: Hunting in case of ammeters and Combination of shunt and swamping resistance in case of voltmeters

65)   The frequency errors in induction instruments can be compensated by the use of a. Non inductive shunt in both ammeters and voltmeters b. Non inductive shunt in case of ammeters and are generally self compensated in case of voltmeters c. Self compensated in case of both ammeters and voltmeters d. Self compensated in case of ammeters and non inductive shunt in case of voltmeters Answer   ANSWER: Non inductive shunt in case of ammeters and are generally self compensated in case of voltmeters

66)   For reducing the errors in an induction instrument the alternating current to be measured has a. Same frequency with which the instrument was calibrated b. High frequency compared with which the instrument was calibrated c. Low frequency compared with which the instrument was calibrated d. None of these Answer   ANSWER: Same frequency with which the instrument was calibrated

67)   In induction voltmeter, split phase windings are obtained by connecting a a. High resistances in series with windings of both the magnets b. High resistance in series with the winding of one magnet and an inductive coil in series with the windings of other magnet c. An inductive coil in series with the winding of one magnet and a capacitance in series with the windings of other magnet d. Inductive coils in series with the winding of both the magnets Answer   ANSWER: High resistance in series with the winding of one magnet and an inductive coil in series with the windings of other magnet

68)   A cylindrical type with split phase winding induction ammeters employs a. A rotating disc b. A hollow aluminium drum c. A single flux producing winding d. Either (a) or (b) Answer   ANSWER: A hollow aluminium drum

69)   Induction type instruments are generally used as a. Ammeter b. Voltmeter c. Wattmeter d. All of these e. None of these Answer   ANSWER: All of these

70)   Damping torque is the torque which acts on a. Stationary system of the instrument b. Moving system of the instrument only when it is stationary c. Moving system of the instrument only when it is moving d. Stationary system of the instrument only when the moving system is moving Answer   ANSWER: Moving system of the instrument only when it is moving

71)   A deflection of 90 degree is produced when a current of 10 A flows through the circuit and the torque of the ammeter vary as the square of the current through it. If a current of 8 A flows through it, then the deflection obtained when the instrument is spring controlled and when the instrument is gravity controlled are a. 39.79 degree, 57.6 degree b. 47.55 degree, 35.67 degree c. 57.6 degree, 39.79 degree d. 35.67 degree, 47.55 degree Answer   ANSWER: 57.6 degree, 39.79 degree

72)   The gravity controlled instruments has to be kept  a. Vertical b. Horizontal c. Inclined at 45 degree d. Inclined at 75 degree Answer   ANSWER: Vertical

73)   Random errors in a measurement system are due to a. Environmental changes b. Use of uncalibrated instrument c. Poor cabling practices d. Unpredictable effects Answer   ANSWER: Unpredictable effects

74)   Calibration of instrument is an important consideration in measurement system. The errors due to instruments being out of calibration can be rectified by a. Increasing the frequency of recalibration b. Increasing the temperature coefficient c. Increasing the susceptibility of measuring instrument d. Decreasing the frequency of recalibration Answer   ANSWER: Increasing the frequency of recalibration

75)   The undesirable characteristics of a measuring system is / are a. Drift b. Dead zone c. Non linearity d. All of these Answer   ANSWER: All of these

76)   If the instrument is used in wrong manner while application, then it will results in a. Systematic error b. Instrument error c. Random error d. Environmental error Answer   ANSWER: Instrument error

77)   Suitable method for the reduction of systematic errors is / are a. Instrument must be designed carefully b. By introducing an equal and opposite environmental input for compensating the effect of environmental input in a measurement system c. By adding high gain feedback to measurement system d. All of these Answer   ANSWER: All of these

78)   The systematic errors of an instrument can be reduced by making a. The sensitivity of instrument to environmental input as low as possible b. The sensitivity of instrument to environmental input as high as possible c. Systematic errors does not depend on the sensitivity of instrument d. None of these Answer   ANSWER: The sensitivity of instrument to environmental input as low as possible

79)   The magnitude of environment - induced variation from the specified calibration condition is quantified by a. Sensitivity drift b. Zero drift c. Backlash d. Both (a) & (b) Answer   ANSWER: Both (a) & (b)

80)   In a moving coil voltmeter, the input resistance of the meter can be increased by  a. Increasing the number of turns in the coil b. Decreasing the number of turns in the coil c. Using the same number of coil turns made up of high resistance material d. Both (a) & (c) Answer   ANSWER: Both (a) & (c)

81)   Depending on whether the display is a numeric or alphanumeric, the segmental display is a. 7 segmental b. 14 segmental c. 21 segmental d. Either (a) or (b) e. None of the above Answer   ANSWER: Either (a) or (b)

82)   The measurements which can be simplified by using X - Y recorders is / are a. Speed - torque characteristics of motors b. Regulation curves of power supplies c. Hysteresis curves d. All of these Answer   ANSWER: All of these

83)   Potentiometer is used for the measurement of  a. Linear displacement b. Angular displacement c. Non - linear displacement d. Only (1) and (2) e. All the above Answer   ANSWER: Only (1) and (2)

84)   The displacement measuring instruments is / are a. Potentiometer b. LVDT c. RVDT d. All of these Answer   ANSWER: All of these

85)   In fibre - optic level sensors, the amount of light loss depends on  a. The proportion of cable that is submerged in the liquid b. Amount of light which is reflected back c. The proportion of cable that is not in the liquid d. Amount of light which is not reflected back Answer   ANSWER: The proportion of cable that is submerged in the liquid

86)   Instrument which is capable of discriminating temperature differences of even 0.1 degree Celsius is a. Fibre - optic level sensors b. Laser method c. Thermography d. Vibrating level sensors Answer   ANSWER: Thermography

87)   Contact devices used for the measurement of level are a. Less reliable then devices which does not make contact with the material b. More reliable then devices which does not make contact with the material c. Less reliable then devices which makes contact with the material d. More reliable then devices which makes contact with the material Answer   ANSWER: Less reliable then devices which does not make contact with the material

88)   With the increase in the intensity of light, the resistance of a photovoltaic cell a. Increases b. Decreases c. Remains same d. None of these Answer   ANSWER: Decreases

89)   For the measurement of pressure the instruments used can be a. Mechanical b. Electro - mechanical c. Electronic d. All of these e. None of these Answer   ANSWER: All of these

90)   If at one end, the two wires made of different metals are joined together then a voltage will get produced between the two wires due to difference of temp between the two ends of wires. This effect is observed in a. Thermocouples b. Thermistors c. RTD d. Ultrasonics Answer   ANSWER: Thermocouples

91)   Primary current in a current transformer is determined by a. The load on the system b. The load on its own secondary c. The load on its own primary d. All of these Answer   ANSWER: The load on the system

92)   The transformer ratio of the transformer depends upon the  a. Exciting current b. Secondary current c. Power factor of secondary circuit d. All of these Answer   ANSWER: All of these

93)   During load test on 3 phase induction motor, the readings of the two wattmeters are -5.5 kW and +12.5 kW respectively. If the line voltage is 420 V then the line current will be a. 38.91 A b. 41.02 A c. 42.10 A d. 43.94 A Answer   ANSWER: 43.94 A

94)   If the reading of the two wattmeters is equal and opposite while measuring power in a 3 phase induction motor then the power factor of the load will be a. Unity b. Zero c. 0.5 lagging d. 0.5 leading Answer   ANSWER: Zero

95)   The full scale current of a galvanometer with internal resistance of 800 ohm is 8 A. what will be the multiplying power of 80 ohm shunt with this galvanometer? a. 8 b. 9 c. 10 d. 11 Answer   ANSWER: 11

96)   In L - C connected wattmeter, compensated coil is used. The error in the wattmeter is due to power consumed by the a. Current coil b. Potential coil c. Inductor d. Capacitor Answer   ANSWER: Potential coil

97)   The AC Bridge which is used for the measurement of frequency is a. Schering bridge b. Wien bridge c. Hay’s bridge d. Anderson bridge Answer   ANSWER: Wien bridge

98)   Schering bridges are used for the measurement of  a. Unknown capacitance b. Dielectric loss c. Power factor d. All of these e. None of these Answer   ANSWER: All of these

99)   The bridge suitable for the measurement of capacitance is / are a. Anderson’s bridge b. Hay’s bridge c. Owen’s bridge d. None of these Answer   ANSWER: None of these

100)   The method / methods suitable for the measurement of low resistance is / are a. Ammeter - voltmeter method b. Kelvin’s double bridge method c. Potentiometer method d. All of these Answer   ANSWER: All of these

101)   A highly sensitive galvanometer is used in Wheatstone bridge and it can detect a current as low as 80 pA. The resistances of each arm of bridge are 800 ohm and the resistance of galvanometer is 40 ohm. If an input of 20 V is applied to the bridge then the smallest change in resistance which can be detected is a. 10.752 μA b. 15.280 μA c. 17.351 μA d. 23.719 μA Answer   ANSWER: 10.752 μA

102)   In a Wheatstone bridge, if P = 10 ± 1%, Q = 100 ± 1%, R = 20 ± 1% and S is unknown then the unknown resistance will be a. 200 ± 1% b. 200 ± 2% c. 200 ± 3% d. 100 ± 1% Answer   ANSWER: 200 ± 3%

103)   The heater wire of thermocouple instruments are made of smaller area of cross section to  a. reduce the skin effect b. reduce temperature error c. reduce frequency error d. increase inductance Answer   ANSWER: reduce the skin effect

104)   The thermocouple ammeter scale is  a. Linear b. Cramped at low end and open at high end c. Open at low end and cramped at high end d. Cramped at the middle Answer   ANSWER: Cramped at low end and open at high end

105)   The thermocouple instruments works on the principle of Seebeck effect. The amount of heat produced is a. Directly proportional to the current b. Directly proportional to the square of current c. Inversely proportional to the current d. Inversely proportional to the square of current Answer   ANSWER: Directly proportional to the square of current

106)   In a portable instrument, the effect of stray magnetic field on actuating torque will be maximum when the operating field and stray fields are a. Parallel to each other b. Perpendicular to each other c. Inclined at 45 degree d. Opposite to each other Answer   ANSWER: Parallel to each other

107)   Megger is a portable instrument. It is used for the measurement of a. Low inductance b. Low resistance c. High inductance d. High resistance Answer   ANSWER: High resistance

108)   In the given frequency range, which type of instrument will have highest accuracy a. electrodynamometer b. hot - wire instrument c. electrostatic instrument d. PMMC Answer   ANSWER: electrodynamometer

109)   Power consumption in permanent magnet moving coil instrument and hot - wire instruments are a. Low, low b. Low, high c. High, low d. High, high Answer   ANSWER: Low, high

110)   The current sensitive instruments are a. PMMC b. Hot wire instruments c. Electrostatic instruments d. Both (a) and (b) Answer   ANSWER: Both (a) and (b) 111)   The scales of gravity controlled instruments are a. Uniform b. Non - uniform and cramped or crowded at the middle c. Non - uniform and cramped or crowded at their lower ends d. Non - uniform and cramped or crowded in the first half Answer   ANSWER: Non - uniform and cramped or crowded at their lower ends 112)   In a gravity controlled type indicating instrument, the current flowing through the circuit is a. Directly proportional to the cosine of angle of deflection b. Directly proportional to the sine of angle of deflection c. Directly proportional to the tan of the angle of deflection d. Directly proportional to the angle of deflection Answer   ANSWER: Directly proportional to the sine of angle of deflection 113)   If the impedance of the instrument measuring the output voltage of the bridge circuit is less than the component resistance then a. The instrument will load the bridge circuit b. The instrument will draw current from the circuit c. Supply current to the circuit d. Both (a) & (b) e. None of the above Answer   ANSWER: Both (a) & (b) 114)   In bridge circuit, the impedance of the instrument measuring the output voltage must be a. Equal to the component resistance of the circuit b. Very large compared to the component resistance of the circuit c. Very small compared to the component resistance d. Less than compared to the component resistance but not very small Answer   ANSWER: Very large compared to the component resistance of the circuit 115)   Systematic errors in a measurement system are caused by  a. System disturbance during measurement b. Effect of environmental changes c. Use of uncalibrated instruments d. All of these Answer   ANSWER: All of these 116)   In the systematic errors, the errors in the output of the measurement system are a. All the errors will be positive b. All the errors will be negative c. Either all the errors will be positive or all the errors will be negative d. None of the these Answer   ANSWER: Either all the errors will be positive or all the errors will be negative 117)   The difference between the measured value and the true value is known as a. Relative error b. Random error c. Absolute error d. Systematic error Answer   ANSWER: Absolute error 118)   The process of measurement  a. Always disturbs the system being measured b. It may or may not disturb the system being measured c. Never disturbs the system being measured d. None of these Answer   ANSWER: Always disturbs the system being measured 119)   Commercial accelerometer, which is a second order instruments are generally designed for the damping ratio of the range of a. 0.2 – 0.4 b. 0.6 – 0.8 c. 0.707 – 1 d. 1 – 1.5 Answer   ANSWER: 0.6 – 0.8

120)   For a second order instrument if the value of the damping ratio is equal to zero, then the

a. Output will exhibit constant amplitude oscillation

b. Initially output will be oscillatory and gradually it will die down

c. Initially output will be oscillatory and gradually amplitude of oscillation will increase

d. Output does not exhibit any oscillations

Answer

ANSWER: Output will exhibit constant amplitude oscillation

121)   X - Y recorder is the type of a. Graphic recorders b. Oscillographic recorders c. Magnetic tape recorders d. Digital recorders Answer   ANSWER: Graphic recorders

122)   The different types of analog recorders are a. Graphic recorders b. Oscillographic recorders c. Magnetic tape recorders d. All of these Answer   ANSWER: All of these

123)   A vibrating level sensors consist of  a. One piezoelectric oscillators b. Two piezoelectric oscillators c. Three piezoelectric oscillators d. Four piezoelectric oscillators Answer   ANSWER: Two piezoelectric oscillators

124)   In radiation methods, the detector system is located a. At the top of the liquid filled tank b. At the bottom of liquid filled tank c. In middle of the liquid filled tank d. Outside a liquid filled tank Answer   ANSWER: Outside a liquid filled tank

125)   If the ambient temperature is doubled and pressure fluctuates, then the transmission time of radar through air is  a. Almost unaffected and remains same b. Increases c. Decreases d. None of these Answer   ANSWER: Almost unaffected and remains same

126)   The transducer used for the measurements is / are a. Resistance temperature detectors b. Thermistors c. Ultrasonic d. All of these Answer   ANSWER: All of these

127)   The linear variable differential transformer transducer is a. Inductive transducer b. Non - inductive transducer c. Capacitive transducer d. Resistive transducer Answer   ANSWER: Inductive transducer

128)   Constantan is used for measurement of dynamic strains. It is an alloy of a. Constantan is used for measurement of dynamic strains. It is an alloy of b. Nickel and molybdenum c. Nickel and chromium d. Copper and nickel Answer   ANSWER: Copper and nickel

129)   Strain gauge is a  a. Active device and converts mechanical displacement into a change of resistance b. Passive device and converts electrical displacement into a change of resistance c. Passive device and converts mechanical displacement into a change of resistance d. Active device and converts electrical displacement into a change of resistance Answer   ANSWER: Passive device and converts mechanical displacement into a change of resistance

130)   Thermistor is a transducer. Its temperature coefficient is a. Negative b. Positive c. Zero d. None of these Answer   ANSWER: Negative 131)   For the measurement of energy and power it is essential to know  a. Only the transformation ratio b. Phase angle between the primary and secondary currents c. Both (a) and (b) d. None of these Answer   ANSWER: Both (a) and (b) 132)   Current transformers and potential transformers are used to increase the ranges of a. AC ammeter and AC voltmeter respectively b. AC ammeter and DC voltmeter respectively c. DC ammeter and DC voltmeter respectively d. DC ammeter and AC voltmeter respectively Answer   ANSWER: AC ammeter and AC voltmeter respectively 133)   If the reading of one wattmeter is four times the other wattmeter while measuring the input power of 3 phase induction motor then the power factor of the load will be a. 0.56 b. 0.69 c. 0.74 d. 0.81 Answer   ANSWER: 0.69 134)   What will be the power factor of an inductive load if the reading of the two wattmeters connected to measure input power of a 3 phase induction motor is 6: 3? a. 0.86 b. 0.89 c. 0.91 d. 0.95 Answer   ANSWER: 0.86 135)   The readings of the two wattmeter used for the measurement of power input to a 3 phase induction motor are 850 W and 250 W respectively. The power factor of the motor is a. 0.73 b. 0.76 c. 0.79 d. 0.85 Answer   ANSWER: 0.73 136)   A wattmeter has a pressure coil resistance of 5K ohm and current coil resistance of 0.02 ohm. What load will give equal error with the two connections if the load current is 15 A at a voltage of 240 V and 0.8 power factor. a. 20 A b. 24 A c. 28 A d. 32 A Answer   ANSWER: 24 A 137)   The Schering bridges can be used at a. low voltage b. high voltage c. medium voltage d. both (a) and (b) e. all the above Answer   ANSWER: both (a) and (b) 138)   If δ is the loss angle then the dissipation factor is given by  a. sin δ b. cos δ c. tan δ d. cot δ Answer   ANSWER: tan δ 139)   The dielectric loss of pure capacitor is equal to a. 1 b. 0 c. Maximum d. None of these Answer   ANSWER: 0 140)   To produce a change of 2 mm in deflection of galvanometer, a change of 4 ohm is required in the unknown arm of a Wheatstone bridge. The sensitivity of the galvanometer is a. 1 mm / ohm b. 0.5 mm / ohm c. 1.5 mm / ohm d. 2 mm / ohm Answer   ANSWER: 0.5 mm / ohm

141)   The resistances of the various arms of Wheatstone bridge are P = 500 ohm, Q = 50 ohm, R = 1010 ohm and S = 100 ohm. The emf of the batter is 5 V and the current sensitivity of galvanometer is 8 mm / μ A. If the internal resistance of the galvanometer is 80 ohm then the deflection of galvanometer and the sensitivity of the bridge in terms of deflection per unit change of resistance are a. 151.2 mm, 30.24 mm / ohm b. 100 mm, 21.03 mm / ohm c. 186 mm, 40.37 mm / ohm d. 193 mm, 20.74 mm / ohm Answer   ANSWER: 151.2 mm, 30.24 mm / ohm

142)   Wheatstone bridge is suitable for the measurement of a. Low resistance b. Medium resistance c. High resistance d. Very high resistance Answer   ANSWER: Medium resistance

143)   Hot - wire instruments are suitable for a. AC work only b. DC work only c. Both AC and DC work d. None of these Answer   ANSWER: Both AC and DC work

144)   The deflection angle in hot wire instruments is a. Directly proportional to the current b. Directly proportional to the square of current c. Inversely proportional to the current d. Inversely proportional to the square of current Answer   ANSWER: Directly proportional to the square of current

145)   For a dynamometer wattmeter, the variation of inductance with angular position of moving system is 0.06 mH/radian and spring constant is 10 X 10-6 N -m / radian. The current flowing in the instrument is 8 A. If the full scale deflection is 76 degree, then the current required in the voltage coil at full scale in d.c. circuit is a. 27.6 μA b. 29.89 μA c. 35.3 μA d. 37.28 μA Answer   ANSWER: 27.6 μA

146)   A electrodynamic ammeter has current flowing through it of 20 A and torsional constant of controlling spring of 10-6 N - m / degree. If the mutual inductance changes uniformly at the rate of 0.0025 μ H / degree, then its angular deflection for full scale is  a. 43.68 degree b. 57.29 degree c. 68.32 degree d. 69.69 degree Answer   ANSWER: 57.29 degree

147)   In an electrodynamic instrument, the number of control springs present is / are a. Two b. One c. Four d. Zero Answer   ANSWER: Two

148)   The scale of electrodynamic instrument when it is used as ammeter and when it is used as voltmeter is a. Uniform, uniform b. Crowded near zero, crowded near zero c. Cramped near zero, cramped in the middle d. Uniform, cramped near zero Answer   ANSWER: Crowded near zero, crowded near zero

149)   The equivalent inductance of fixed coil and moving coil of electrodynamic instrument is given by a. L1 + L2 + 2M b. L1 + L2 - 2M c. L1 + L2 + M d. L1 + L2 - M Answer   ANSWER: L1 + L2 + 2M

150)   Electrodynamic instruments can be used as a. Ammeter b. Voltmeter c. Wattmeter d. All of these Answer   ANSWER: All of these

151)   In measuring instruments, spiral springs are provided to a. Lead current b. Produce controlling torque c. Produce damping torque d. Lead current and produce controlling torque Answer   ANSWER: Lead current and produce controlling torque

152)   In a spring controlled type indicating instruments, if the controlling torque is equal to the deflecting torque then a. Angle of deflection will be maximum b. Current flowing through it will be maximum c. Angle of deflection will be zero d. Angle of deflection will be directly proportional to the current flowing through it Answer   ANSWER: Angle of deflection will be directly proportional to the current flowing through it

153)   If a balloon is equipped with temperature and altitude measuring instruments, then the order of the temperature measuring and altitude measuring instruments are a. Zero order, first order b. Both are first order instruments c. Both are zero order instruments d. First order, zero order Answer   ANSWER: First order, zero order

154)   A zero order system is the one in which output changes instantaneously as the input changes. The example of zero order system is a. Potentiometer b. Liquid - in - glass thermometer c. Accelerometer d. Transducer Answer   ANSWER: Potentiometer

155)   Backlash is commonly experienced in gear sets used to convert between translational and rotational motion. Backlash is a typical cause of  a. Hysteresis b. Dead space c. Zero drift d. Sensitivity drift Answer   ANSWER: Dead space

156)   If an instruments exhibits hysteresis then a. It also displays dead space b. It will not display any dead space c. Either (a) or (b) d. None of these Answer   ANSWER: It also displays dead space

157)   In a measuring instrument, dead space is defined as the  a. Range of different input values over which there is no change in output values b. Range of different output values for the same input values c. Either (a) or (b) d. None of these Answer   ANSWER: Range of different input values over which there is no change in output values

158)   Hysteresis most commonly occurs in instruments that contains a. Springs b. Electrical windings formed round on iron core c. Both (a) and (b) d. None of these Answer   ANSWER: Both (a) and (b)

159)   The non coincidence between loading and unloading curves is known as a. Zero drift characteristics b. Sensitivity drift characteristics c. Hysteresis d. Zero drift plus sensitivity drift characteristics Answer   ANSWER: Hysteresis

160)   Can an instrument suffer both zero drift and sensitivity drift at the same time? a. Yes b. No c. It depends on the supply voltage d. None of these Answer   ANSWER: Yes 161)   Q meter is used to measure the properties of a. Inductive coils b. Non inductive coils c. Capacitive coils d. Both (a) and (c) Answer   ANSWER: Both (a) and (c) 162)   In the beginning, all the outputs of the successive approximation type register is at a. Logic zero b. Logic one c. Toggling d. None of these Answer   ANSWER: Logic zero 163)   In ultrasonic level gauge, the ultrasonic source is placed at the a. Bottom of the vessel containing the liquid b. Top of the vessel containing the liquid c. Middle of the vessel containing the liquid d. Far from the vessel containing the liquid Answer   ANSWER: Bottom of the vessel containing the liquid 164)   Capacitive devices are used for the level measurement of a. Only liquid b. Solid in powdered form c. Both (a) and (b) d. None of these Answer   ANSWER: Both (a) and (b) 165)   The most common application of float system is a. To monitor the fuel tank level in motor vehicle b. To monitor the flow of solid c. To monitor the flow of liquid d. All of these Answer   ANSWER: To monitor the fuel tank level in motor vehicle Explanation:  No explanation is available for this question! 166)   Potentiometric transducers are used for the measurement of a. Pressure b. Displacement c. Humidity d. Both (a) and (b) Answer   ANSWER: Both (a) and (b) 167)   Function of transducer is to convert  a. Electrical signal into non electrical quantity b. Non electrical quantity into electrical signal c. Electrical signal into mechanical quantity d. All of these Answer   ANSWER: Non electrical quantity into electrical signal 168)   The phase difference between two waveforms in the below figure is given by a. ∅ = sin -1 Y1 / Y2 b. ∅ = sin -1 Y2 / Y1 c. ∅ = tan -1 Y2 / Y1 d. ∅ = tan -1 Y1 / Y2 Answer   ANSWER: ∅ = sin -1 Y1 / Y2 169)   For friction compensation in an induction watt-hour meter is done by making  a. The ratio of the shunt magnet flux and series magnet flux large with the help of two shading bands b. The ratio of the series magnet flux and shunt magnet flux large with the help of two shading bands c. The ratio of the shunt magnet flux and series magnet flux large with the help of three shading bands d. The ratio of the series magnet flux and shunt magnet flux large with the help of three shading bands Answer   ANSWER: The ratio of the shunt magnet flux and series magnet flux large with the help of two shading bands 170)   In induction watt - hour meter, due to shunt magnet the torque is not zero power factor. It can be compensated by using a. Shading ring b. Power factor compensator c. Drilling holes in the disc on a diameter d. Both (a) and (b) Answer   ANSWER: Both (a) and (b)

171)   The scale of induction wattmeter extends over a. 70 degree b. 120 degree c. 180 degree d. 300 degree Answer   ANSWER: 300 degree

172)   In induction type wattmeter both current and pressure coils are required. For obtaining the required phase difference  a. Shaded pole principle is used b. Two separate ac magnets are used c. Only one ac magnets are used d. All of these Answer   ANSWER: Two separate ac magnets are used

173)   The frequency and supply voltage of induction wattmeters are a. Constant, constant b. Constant, variable c. Variable, constant d. Variable, variable Answer   ANSWER: Constant, constant

174)   Induction wattmeters can be used with  a. Only AC supply b. Only DC supply c. Both AC and DC supply d. None of these Answer   ANSWER: Only AC supply

175)   Anderson bridges is suitable for the measurement of a. Resistance b. Inductance c. Capacitance d. All of these Answer   ANSWER: Inductance

176)   The Hay’s bridge is suitable for the measurement of inductances of coils with Q factor  a. More than 10 b. Less than 1 c. More than 1 d. Less than 10 Answer   ANSWER: More than 10

177)   If C4 is the capacitance and R4 is the resistance of Hay’s bridge, then the Q factor of Hay’s bridge is given by a. 1 / (ω C4 R4) b. ω C4 R4 c. (ω C4) / R4 d. (ω R4) / C4 Answer   ANSWER: 1 / (ω C4 R4)

178)   During a test, the strain gauge with resistance of 200 ohm undergoes a change of 0.120 ohm and the strain of the gauge is 1.2 X 10 -4. Then the gauge factor will be a. 4 b. 5 c. 4.5 d. 6 Answer   ANSWER: 5

179)   The sensitivity of the bridge is maximum when a. P / R = Q / S = 0 b. P / R = 1 c. Both (a) and (b) d. None of the above Answer   ANSWER: P / R = 1

180)   The sensitivity of Wheatstone bridge is defined as ratio of a. Deflection of the galvanometer to the unit fractional change in the value of unknown resistance b. Square of the deflection of the galvanometer to the unit fractional change in the value of unknown resistance c. Deflection of the galvanometer to the twice of the unit fractional change in the value of unknown resistance d. Unit fractional change in the value of unknown resistance to the deflection of the galvanometer Answer   ANSWER: Deflection of the galvanometer to the unit fractional change in the value of unknown resistance                                          Click Here for mcqs from 181 to 360