VIDYA PRATISHTHAN’S COLLEGE OF ENGINEERING, BARAMATIDepartment of Electrical Engineering

Electrical Measurement and Istrumentation

MCQ Class test

Note : Write your answer in given table at the end

1. If torque/weight ratio of an instrument is low, then it can be concluded that a. The meter will have uniform scaleb. The meter will have non uniform scalec. The sensitivity of the meter will be highd. The sensitivity of the meter will be low

2. Which of the following instrument can be used for DC onlya. Moving iron instrument typeb. Moving iron repulsion typec. Permanent Magnet typed. Hot wire type

3. A 50 V range voltmeter has a sensitivity of 20 K ohm/V. The total resistance of the voltmeter is a. 2.5 K ohm b. 0.4 K ohm c. 10 K ohm d. 1 Mega ohm

4. In spring control the controlling torque is varies as a. Sin Ө b. Ө c. Ө2 d. 1/Ө

5. In a 3-phase power measurement by two wattmeter method thereading of one of the wattmeter was zero. The power factor of the load must be

a unity b . 0.5 c 0.3 d. zero

6. The multiplying power of the shunt of a milliammeter is 8. If the circuit current 200 mA, then current through the meter is a. 200 mA b. 25 mA c. 1600 mA d. none of the above

7. A moving coil instrument having meter resistance of 5 ohm is to be used as a voltmeter of range 0 -100 v. If the full scale deflection current is 10 mA, then required series resistance is a. 20 ohm b. 1000 ohm c. 9995 ohm d. none of the above

8. A moving coil voltmeter gives full scale deflection of 100 v for meter current of 1 mA. For 45 V reading meter current will be a. 0.45 mA b. 1.45 mA c. 2.22 mA d. none of the above

9. If a wattmeter connected in circuit gives down scale reading , then we normally change connection of a. Current coil b. Potential coil c. Both PC and CC d. None of the above.

10. The range of moving iron ac ammeter is extended by a. Shunt b. Multiplier c. changing number of turns of operating coil. d. None

11. A pointer of an instrument once deflected returns to zero position, when current is removed due to a. Action of gravity b. Mass of pointer c. Controlling torque d. Damping torque

12. Which of the torque does not effect act on the moving system when an indicating instrument shows a steady non zero reading

a. The deflecting torque c. The controlling torqueb. The restraining torque d. The damping torque

13. The multiplier and the meter coil in voltmeter are ina. Series b. Parallel c. Series parallel d. none of the above

14. Power being measured by two wattmeter method in balanced three phase system , the wattmeter reading are W1 = 250 KW , W2 = 50 KW. If the later reading is obtained after reversing the connection to the current coil of W2, the power factor of the loada. Unity b. 0.655 c. 0.5 d. 0.359

15. The power in a three phase four wire balanced circuit can be measured by usinga. Two wattmeter method c. One watt meter methodb. Three wattmeter method d. Any method can be used

16. The scale of dynamometer type watt meter is ` a. Uniform b. non uniform c. depends on range d. none of the above

17. A dyanamometer wattmeter can be used for a. Both Ac and DC b. DC only c. AC Only d. any of the above

18. Swamping resistance is connected

a. In series with the shunt to reduce temperature error.

b. In series with the ammeter to reduce shunted ammeter error on account of friction.

c. In series with the ammeter and have a high resistance temperature co-efficient in order to reduce temperature error in ammeter.

d. In series with the ammeter and have a negligible resistance co efficient in order to reduce temperature error in shunted ammeter.

19. Which meter has the highest accuracy in the prescribed limit of frequency rangea. PMMC b. Moving iron c. Electrodynamometer d. Rectifier

20. If an instrument is précised thena. It may be accurate b. may not be accurate c. both a and b d. none

21. ……is the measure of consistency or repeatability of measurementa. Accuracy b. Resolution c. Measurement d. Precision

22. The smallest measureable input is called……. Of an instrument.a. Threshold b. linearity c. resolution d. sensitivity

23. The ability of a instrument to retain its performance through out its specified operating life is calleda. Reproducibility b. linearity c. resolution d. stability.

24. …… is not the dynamic characteristic of instrument .a. Fidelity b. Bias c. speed of response. D. lag

25. Backlash in gears is good example of …..a. Zero drift b. tolerance c. dead zone d. linearityb.

Q 1 2 3 4 5 6 7 8 9 10 11 12 13A

Q 14 15 16 17 18 19 20 21 22 23 24 25A

1. (d) low sensitivity2. C. Permanent magnet type3. D 1 mega ohm4. D 1/teta5. 60 degree or 0.5 pf6. I/Im = 8, 200/8 = Im 25mA7. 100/10 mA – Rm =10000-5 = 9995 ohm8. (1/100) x 45 = .45 m A9. PC only10. By changing num of turns11. Controlling12. Damping13. 13 series14. 0.35915. One wattmeter16. Non uniform17. Both ac and Dc

18. D 19. Electrodynamometer20. C21. D22. A23. D24. B25.