Electrical Measurements MCQ|Objective Questions On Electrical Measurements

Electrical Measurements MCQ

In measurement systems, which of the following static characteristics are desirable :

(a) Accuracy (b) Sensitivity

2. In measurement systems, which of the following are undesirable static characteristics :

(a) Sensitivity and accuracy

(b) Drift, static error and dead zone

(d) Drift, static error, dead zone and non-linearity.

3. A pressure measurement instrument is calibrated between 10 bar and 250 bar. The scale span of the instrument is

(a) 10 bar (b) 250 bar

while the scale range is

(a) 10 bar (b) 250 bar

4. The output of an instrument under particular environmental conditions is given by the relationship

q₀=a + bq_i where = input and a and b are constants b ≠1. The theoretical input-output relationship

is represented by a straight passing through zero. This is a case of

(a) zero drift only

(b) sensitivity drift only

(d) none of the above.

5. A reading is recorded as 23.90 C°. The reading has

(a) three significant figures

(b) five significant figures

(d) none of the above.

6. The scale of a 0-500 V voltmeter is divided into ten large divisions representing 50 V each and each

large division is further subdivided into 10 small divisions, each representing 5 V. It is used for measurement of output voltage of a potentiometer which can be varied from 0 to 500 V. It is observed that when the sliding contact is moved from its zero position, there is no perceptible movement of pointer of the voltmeter till the sliding contact reaches a position where the output voltage should

be 5 V. Therefore, it can be concluded that

(a) the threshold of the voltmeter is 5 V

(b) the resolution of the voltmeter is 5 V

(d) none of the above.

7. In the centre zero analog ammeter having a range of -10 A + 10 A, there is a detectable change of the pointer from its zero position on either side of the scale only if the current reaches a value of 1 A (on either side). The ammeter has a

(a) resolution of 1 A

(b) dead zone of 1 A

(d) sensitivity of 1 A.

8. A pressure gauge is calibrated from 0-50 kN/m2. It has a uniform scale with 100 scale divisions. One fifth of a scale division can be read with certainty. The gauge has a :

(a) resolution of 0.1 kN/m2

(b) threshold of 0.1 kN/m2

(d) a resolution of 0.5 kN/m2.

9. A d.c. circuit can be represented by an internal voltage source of 50 V with an output resistance of 100 kΩ In order to achieve 99 percent accuracy for voltage measurement across its terminals, the voltage measuring device should have

(a) a resistance of atleast 10 MQ

(b) a resistance of 100 kQ

(d) none of the above.

10. A d.c. circuit can be represented by a voltage source of 10 V in series with an output resistance

of 1 kD. An ammeter of 50 Q resistance is connected to the source terminals for measurement

of current. The accuracy of measurement is nearly

(a) – 4.8 percent (b) + 4.8 percent

11. In a.c. circuits, the connection of measuring instruments cause loading errors which may affect

(a) only the magnitude of quantity being measured

(b) only the phase of the quantity being measured

(d) magnitude, phase and also the waveform of the quantity being measured.

12 . The input resistance of a cathode ray oscilloscope is of the order of

(a) tens of ohm

(b) megohm

(cj kilohm

(d) fraction of an ohm.

13. A resistor, at room temperature of 290 °K has a noise voltage of 2 pV for a 50 kHz bandwidth. The temperature at which the noise voltage is 20% of its value at room temperature is

(a) 58 °K

(b) 11.6 °K

(d) none of the above.

14. An amplifier has an input signal voltage of 25 pV and a noise voltage 2.5 p V. The signal to noise ratio is

(a) 10 (b) 100

(cj 10 db (d) none of the above.

1 .Electrical measuring instruments

2. Types of measuring instruments- www.eeemadeeasy.com

3. Measuring devices for Electrical quantities..

4. KSEB Sub Engineer Mock Tests|Mock Test for Sub Engineer KSEB Exam 2023

15. Johonson noise is :

(a) caused by thermal agitation of free electrons carrying current thereby modulating the current

(b) noise carried into a circuit through conductors

(d) shot noise which results from random emission of electrons across a p-n junction.

16. In a measurement system if a q} is an across variable and its associated through variable is q2 (power based), the static impedance of the system is :

17. In a measurement system force’ is an across variable. Its associated power based through variable is :

(a) translational displacement

(b) translational acceleration

(d) rotational displacement.

18. The power can be controlled in a circuit by :

(a) controlling the voltage applied to load

(b) controlling the current level in the circuit

(d) all the above.

19. The values of static stiffness and compliance in a measurement system determine the amount of

(a) power drain from a system

(b) current drain from a system

(J) none the above.

20. A Wheatstone bridge is balanced with all the four resistances equal to 1 kQ each. The bridge supply voltage is 100 V. The value of one of the resistances is changed to 1010 Q. The output voltage is measured with a voltage measuring device of infinite resistance. The bridge sensitivity is :

(a) 10 V/Ω

(b) 25 mV/Ω

(d) none of the above.

1. (d) 2. (d) 3. (c) 4. (c) 5. (c) 6. (a) 7. (c) 8. (a) 9. (a) 10. (d) 11. (d) 12. (b) 13. (b) 14. (b) 15. (a) 16. (b) 17. (c) 18. (d) 19. (c) 20. (b)

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