Electrical Measurement and Instruments 4

Electrical Engineering MCQ Question Papers: Campus Placement

Subject: Electrical Measurement and Instruments 4

Part 4: List for questions and answers of Electrical Measurement & Instruments

Q1. Potentiometer method of DC voltage measurement is more accurate than direct measurement using a voltmeter because

a) It loads the circuit moderately

b) It loads the circuit to maximum extent

c) It uses centre zero galvanometer instead of voltmeter

d) It does not load the circuit at all

Q2. Assertion (A): A hot wire ammeter has a cramped scale. Reason (R): The heat is proportional to square of current

a) Both A and R are true and R is correct explanation of A

b) Both A and R are true and R is not correct explanation of A

c) A is ture and R is false

d) A is false and R is ture

Q3. A Managing swap resistance is connected in series with a moving coil ammeter consisting of a milli ammeter and a suitable shunt in order to

a) Minimize the effect of temperature variation

b) Obtaine large deflecting torque

c) Reduce the size of the meter

d) Minimize the effect of stray magnetic fields

Q4. A DC A-h meter is rated for 15 A, 250 V. The meter constant is 14.4 A-sec/rev. The meter constant at rated voltage may be expressed as

a) 3750 rev/KWh

b) 3600 rev/KWh

c) 1000 rev/KWh

d) 960 rev/KWh

Q5. The meter constant of a single phase 240 V induction watthour meter is 400 revolutions per KWh. The speed of the meter disc for a current of 10 Amperes of 0.8 p.f lagging will be

a) 21.1 rpm

b) 18.2 rpm

c) 16.02 rpm

Q6. Piezoelectronic accelerometer

a) Have a low natural frequency

b) Answer: Should be used low frequency

c) Should not be used for high frequencies above 100 Hz

d) Should use a monitoring source low input impedance

Q7. Which amplifier in used in an electronic multimeter?

a) Wideband amplifier

b) Differential amplifier

c) Power amplifier

d) Butter amplifer

Q8. A DC potentiometer is designed to measure up to about 2V with a slide wire of 800 mm. A standard cell of emf 1.18 V obtains balances at 600 mm. A test cell is seen to obtain balance at 680 mm. The emf of test cell is

a) 1V

b) 1.34V

c) 1.5V

d) 1.7V

Q9. A wheatstone bridge cannot be used for precision measurements because errors are introduced into on account of

a) Contact resistance

c) Thermoelectric emfs

d) All of above

Q10. In above question no. 10, the value of Ld will be

a) Ra Rc Cb

b) Ra Rc / Cb

c) Ra Rb / Cb

d) None of above

Q11. When a potentiometer is used for measurement of voltage of an unknown source, the power consume in the circuit of the unknown source under null condition is

a) High

b) Small

c) Ideally zero

d) Very high

Q12. The calibration of a voltmeter can be carried out by using

a) A frequency meter

b) A potentiometer

c) An ammeter

d) A function generator

Q13. For measuring an AC voltage by an AC potentiometer it is desirable that the supply for the potentiometer is taken from

a) A battery

b) The same source as the unknown voltage

c) A source other than the source of unknown voltage

d) Any of above

Q14. The transfer instrument which is used for Standerton of a polar type AC potentiometer is

a) An electrostatic instruments

b) A moving coil instruments

c) A dynamometer instruments

d) A thermal instruments

Q15. Standardisation of potentiometer is done in order that, they become

a) Accurate

b) Precise

c) Accurate and precise

Q16. A DC potentiometer is the best means available for the measurement of DC voltage because

a) It is based on null balance technique

b) It is possible to standardize before a measurement is undertaken

c) The precision in measurement is independent of the type of the defector used

d) None of above

Q17. A thermo couple ammeter gives full scale deflection of 10 A, when it reads one fifth of the scale, the current will be

a) 2 A

b) 4.47 A

c) 4 A

d) 5.78 A

Q18. A meter has a full-scale deflection of 90 degree at a current of 1 A. The response of the meter is square law. Assuming spring control, the current for a deflection at 45 degree will be

a) 0.25 A

b) 0.50 A

c) 0.67 A

d) 0.70 A

Q19. Ratio of readings of two wattmeter connected to measure power in a balanced 3-phase load is 5:3 and the load is inductive. The power factor at load is

a) 0.6 lag

d) 0.917 lag

Q20. How many times base circuits does a dula frace CRO can have?

a) 1

b) 2

d) 4

Part 4: List for questions and answers of Electrical Measurement & Instruments