Electrical & Electronics Measurement & Instrumentation Test Questions - Set 3

1)   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  Explanation 

ANSWER: Closeness of the output reading to the true value

Explanation:
No explanation is available for this question!


2)   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  Explanation 

ANSWER: Maximum expected error in any reading is 0.1 bar

Explanation:
No explanation is available for this question!


3)   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  Explanation 

ANSWER: Less accurate readings than the instrument with range of 0 - 5 bar

Explanation:
No explanation is available for this question!


4)   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  Explanation 

ANSWER: 4.4%, 95.59%

Explanation:
No explanation is available for this question!


5)   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  Explanation 

ANSWER: Degree of freedom from random errors

Explanation:
No explanation is available for this question!


6)   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  Explanation 

ANSWER: Does not imply anything about measurement accuracy

Explanation:
No explanation is available for this question!


7)   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  Explanation 

ANSWER: Bias in the measurement

Explanation:
No explanation is available for this question!


8)   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  Explanation 

ANSWER: Both I and II are correct

Explanation:
No explanation is available for this question!


9)   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 

ANSWER: Ampere - hour and watt - hour meters

Explanation:
No explanation is available for this question!


10)   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  Explanation 

ANSWER: All the above

Explanation:
No explanation is available for this question!


11)   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  Explanation 

ANSWER: 37.5 V

Explanation:
No explanation is available for this question!


12)   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  Explanation 

ANSWER: Directly proportional to the square of rms current

Explanation:
No explanation is available for this question!


13)   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  Explanation 

ANSWER: 120 mA

Explanation:
No explanation is available for this question!


14)   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  Explanation 

ANSWER: Suitable shunt across its terminal

Explanation:
No explanation is available for this question!


15)   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  Explanation 

ANSWER: 3.5 M Ω

Explanation:
No explanation is available for this question!


16)   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  Explanation 

ANSWER: 2.9 A, 2 A

Explanation:
No explanation is available for this question!


17)   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  Explanation 

ANSWER: Directly proportional to both number of turns and flux density

Explanation:
No explanation is available for this question!


18)   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  Explanation 

ANSWER: Both (a) and (b)

Explanation:
No explanation is available for this question!


19)   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  Explanation 

ANSWER: Insulation resistance of cables and wires

Explanation:
No explanation is available for this question!


20)   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  Explanation 

ANSWER: Wheatstone bridge

Explanation:
No explanation is available for this question!