Electrical Measurements & Units Test Questions - 2

1)   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  Explanation  Related Ques

ANSWER: Output will exhibit constant amplitude oscillation

Explanation:
No explanation is available for this question!


2)   Commercial accelerometer, which is a second order instrument is 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  Explanation  Related Ques

ANSWER: 0.6 – 0.8

Explanation:
No explanation is available for this question!


3)   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  Explanation  Related Ques

ANSWER: Always disturbs the system being measured

Explanation:
No explanation is available for this question!


4)   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  Explanation  Related Ques

ANSWER: Absolute error

Explanation:
No explanation is available for this question!


5)   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 (a) or (b)
d. None of these
Answer  Explanation  Related Ques

ANSWER: Either (a) or (b)

Explanation:
No explanation is available for this question!


6)   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  Explanation  Related Ques

ANSWER: All of these

Explanation:
No explanation is available for this question!


7)   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  Explanation  Related Ques

ANSWER: Very large compared to the component resistance of the circuit

Explanation:
No explanation is available for this question!


8)   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. Both (a) & (b)
d. None of the above
Answer  Explanation  Related Ques

ANSWER: Both (a) & (b)

Explanation:
No explanation is available for this question!


9)   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)
e. None of the above
Answer  Explanation  Related Ques

ANSWER: Both (a) & (c)

Explanation:
No explanation is available for this question!


10)   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)
e. None of the above
Answer  Explanation  Related Ques

ANSWER: Both (a) & (b)

Explanation:
No explanation is available for this question!


11)   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  Explanation  Related Ques

ANSWER: The sensitivity of instrument to environmental input as low as possible

Explanation:
No explanation is available for this question!


12)   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  Explanation  Related Ques

ANSWER: All of these

Explanation:
No explanation is available for this question!


13)   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  Explanation  Related Ques

ANSWER: Instrument error

Explanation:
No explanation is available for this question!


14)   The undesirable characteristics of a measuring system is / are

a. Drift
b. Dead zone
c. Non linearity
d. All of these
Answer  Explanation  Related Ques

ANSWER: All of these

Explanation:
No explanation is available for this question!


15)   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  Explanation  Related Ques

ANSWER: Increasing the frequency of recalibration

Explanation:
No explanation is available for this question!


16)   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  Explanation  Related Ques

ANSWER: Unpredictable effects

Explanation:
No explanation is available for this question!


17)   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  Explanation  Related Ques

ANSWER: Either (a) or (b)

Explanation:
No explanation is available for this question!


18)   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  Explanation  Related Ques

ANSWER: Standard error of the mean

Explanation:
No explanation is available for this question!


19)   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 (a) & (b)
d. Neither (a) nor (b)
Answer  Explanation  Related Ques

ANSWER: Both (a) & (b)

Explanation:
No explanation is available for this question!


20)   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  Explanation  Related Ques

ANSWER: 2 %

Explanation:
No explanation is available for this question!


21)   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  Explanation  Related Ques

ANSWER: ± 2.8 %

Explanation:
No explanation is available for this question!


22)   If the resistance in a circuit is given by 80Ω ± 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  Explanation  Related Ques

ANSWER: ± 0.4 %

Explanation:
No explanation is available for this question!


23)   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  Explanation  Related Ques

ANSWER: ± 3%

Explanation:
No explanation is available for this question!


24)   In a Wheatstone bridge, the formula for finding unknown resistance (R2) is given by

R2 = R2R3/R1

Where, R1= 150Ω± 0.1%

R2 = 250Ω ± 0.1%

R3 = 300Ω ± 0.1%

The value of unknown resistance is

a. R2 = 250Ω ± 0.1%
b. R2 = 300Ω ± 0.3%
c. R2 = 750Ω ± 0.3%
d. R2 = 500Ω ± 0.3%
Answer  Explanation  Related Ques

ANSWER: R2 = 500Ω ± 0.3%

Explanation:
No explanation is available for this question!


25)   What will be the limiting error of the resultant capacitance obtained by connecting two capacitance in parallel where C1 = 250 ± 4μF and C2 = 200 ± 3μF?

a. 3μF
b. 4μF
c. 7μF
d. 1.7μF
Answer  Explanation  Related Ques

ANSWER: 7μF

Explanation:
No explanation is available for this question!


26)   The true power measured by the wattmeter whose range is 500 W and an error of ± 2% of full scale deflection is 150 W. The relative error while reading 150 W will be

a. ± 4%
b. ± 5.39%
c. ± 6.67%
d. ± 1.5%
Answer  Explanation  Related Ques

ANSWER: ± 6.67%

Explanation:
No explanation is available for this question!


27)   A voltmeter connected across an unknown resistance has scale of 0 to 150 V reads 50 V when the current flowing in the circuit is 1 mA. If sensitivity of the voltmeter is 15kΩ/V, then the percentage error due to loading effect is

a. ± 1.5%
b. ± 2.12%
c. ± 2.22%
d. ± 2.5%
Answer  Explanation  Related Ques

ANSWER: ± 2.22%

Explanation:
No explanation is available for this question!


28)   If R1= 15Ω ± 2% and R2= 20Ω ± 2% are the resistance connected in parallel then the value of the resistance for the parallel combination is

a. 8.57Ω± 2%
b. 8.57Ω± 4%
c. 8.57Ω± 3%
d. 8.57Ω± 2.5%
Answer  Explanation  Related Ques

ANSWER: 8.57Ω± 2%

Explanation:
No explanation is available for this question!


29)   The electromagnetic effect is generally utilized for

a. Ammeters
b. Voltmeters
c. Wattmeters and watt-hour meters
d. All of these
Answer  Explanation  Related Ques

ANSWER: All of these

Explanation:
No explanation is available for this question!


30)   The electrostatic effect is utilized for

a. Ammeters
b. Voltmeters
c. D.C. ampere-hour meters
d. Wattmeters
Answer  Explanation  Related Ques

ANSWER: Voltmeters

Explanation:
No explanation is available for this question!


31)   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  Explanation  Related Ques

ANSWER: Ampere - hour and watt - hour meters

Explanation:
No explanation is available for this question!


32)   The moving system in the indicating instruments is subjected to

a. Deflecting torque
b. Controlling torque
c. Damping torque
d. All the above
Answer  Explanation  Related Ques

ANSWER: All the above

Explanation:
No explanation is available for this question!


33)   If the deflection torques on moving system increases then the controlling torque

a. Increases
b. Decreases
c. Remains same
d. None of these
Answer  Explanation  Related Ques

ANSWER: Increases

Explanation:
No explanation is available for this question!


34)   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  Explanation  Related Ques

ANSWER: Will deflect but would not return to its zero position on removing current

Explanation:
No explanation is available for this question!


35)   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  Explanation  Related Ques

ANSWER: Either by spring or by gravity

Explanation:
No explanation is available for this question!


36)   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  Explanation  Related Ques

ANSWER: Directly proportional to the angle of deflection of moving system

Explanation:
No explanation is available for this question!


37)   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  Explanation  Related Ques

ANSWER: Directly proportional to the current flowing through it

Explanation:
No explanation is available for this question!


38)   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  Explanation  Related Ques

ANSWER: All of these

Explanation:
No explanation is available for this question!


39)   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  Explanation  Related Ques

ANSWER: Angle of deflection will be directly proportional to the current flowing through it

Explanation:
No explanation is available for this question!


40)   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  Explanation  Related Ques

ANSWER: Lead current and produce controlling torque

Explanation:
No explanation is available for this question!