Electrical Measuring Devices 6

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Objectives for Electrician and Wireman: Electrical Measuring Devices 6

Part 6: Objective questions and answers of Electrical Measuring Devices

 

Q1. Which instrument is used for measuring the medium resistances directly?

a) Ammeter

b) Megger

c) Ohm meter

d) Voltmeter

 

Q2. Ammeters used for current measurements in circuits with short overload time, differs from other application. Ammeters used in short overload time circuit have:

a) None-linear scale

b) Extended scale

c) Linear scale

d) Fine scale

 

Q3. Which of the following electrical quantities can you measure with a moving coil instrument?

a) D.C. Current and D.C. Voltage

b) D.C. And A.C. Current

c) A.C. Voltage

d) A.C. Current

 

Q4. Which material is used for shunt and multiplier to extend the range of moving coil meters?

a) Phosphor bronze

b) Silver

c) Manganin

d) Nichrome

 

Q5. Shunts and multipliers used in moving coil instruments are made up of manganin. The reason for using the above material is that it has:

a) Positive temperature coefficient of resistance

b) Negative temperature coefficient of resistance

c) Perfectly constant temperature coefficient of resistance

d) Very low (practically constant) temperature coefficient of resistance

 

Q6. Moving iron instruments are used to measure both a.c. And d.c. Quantities. What will happen if the terminals of a moving iron instrument are interchanged in d.c. Circuit?

a) It will give no deflection

b) It will indicate same reading

c) It will give full scale deflection

d) It will deflect in the reverse direction

 

Q7. A house has 4 kw connected loads and is fed by single phase supply. What range energy meter is recommended for the house?

a) 20 amperes

b) 15 amperes

c) 30 amperes

d) 10 amperes

 

Q8. A 3 phase 3 element energy meter of 415 v, 50hz has its pressure coil rated for:

a) 230 volts

b) 240 volts

c) 415 volts

d) 440 volts

 

Q9. The creeping error in energy meter can be arrested by:

a) Replacing the rotating disc with new one

b) Drilling two diametrically opposite holes in the disc

c) Reducing the considerable load

d) Increasing the gap between the disc and permanent magnet

 

Q10. Which type of wattmeter can be used on a.c. Only?

a) Dynamometer type wattmeter

b) Electrostatic type wattmeter

c) Induction type wattmeter

d) Commutator type wattmeter

 

Q11. What type of quantity is measured in ferranti type mercury meter?

a) D.C. Watt hour

b) D.C. Ampere hour

c) A.C. And d.c. Watt hour

d) A.C. Watt hour

 

Q12. In battery powered digital multimeter, LCD display is most commonly used. The reason for this is:

a) Mains power is not available everywhere

b) It requires only a small amount of power

c) LCD can be read even in dark

d) LCD has a bright display

 

Q13. What are the measurements that can be done from a portable digital multimeter without battery?

a) Both voltage and current measurements

b) Except resistance, all other measurements

c) Only current measurement

d) No measurement is possible

 

Q14. On the scale of a power factor meter, the pointer indicates 0.8 leading power factor. this value means that the load is a:

a) Pure capacitance

b) High inductive and low capacitive reactance

c) High resistance and low inductive reactance

d) Low inductive reactance and high capacitive reactance

 

Q15. What precautions you have to take when disconnecting voltmeter from potential transformers?

a) Potential transformers secondary terminals which are open should be insulated

b) Ground the secondary terminals on per circuit

c) The terminals of the potential transformer secondary have to be short circuited

d) After disconnecting, connect a low-resistance shunt between the terminal of the secondary

 

Q16. With the help of multimeter, we can measure:

a) Voltage, current and resistance

b) Power, energy and power factor

c) Insulation resistance and A.C. Current only

d) Ampere hour capacity and D.C current only

 

Q17. For measuring the current, voltage (or) resistance by multimeter, which control switch to be set 

a) Range switch

b) Selector switch

c) Power on – off switch

d) Function switch

 

Q18. How many segments are in both lcd and led, digital multi meter (dmm) display?

a) 9

b) 8

c) 7

d) 6

 

Q19. Two types of multimeter are in use. Analog type and digital type. Choose the correct statements applicable for both the types. Both the meters:

a) Have moving elements, hence must be used in horizontal position

b) Can be used for current and voltage measurement without battery

c) Needs manual zero setting for resistance measurement

d) Needs battery for resistance measurements

 

Q20. Which type of scale is used primarily in moving coil measuring device?

a) Non-linear scale

b) Extended scale

c) Linear scale

d) Fine scale

 

Part 6: Objective questions and answers of Electrical Measuring Devices

 

Q1. Answer c

 

Q2. Answer b

 

Q3. Answer a

 

Q4. Answer c

 

Q5. Answer d

 

Q6. Answer b

 

Q7. Answer c

 

Q8. Answer b

 

Q9. Answer b

 

Q10. Answer c

 

Q11. Answer b

 

Q12. Answer b

 

Q13. Answer d

 

Q14. Answer d

 

Q15. Answer a

 

Q16. Answer a

 

Q17. Answer d

 

Q18. Answer c

 

Q19. Answer d

 

Q20. Answer c

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