Thermal or Electrothermic Instruments - Multiple Choice Questions and Answers

Thermal or Electrothermic Instruments - Multiple Choice Questions and Answers Points : Thermal or Electrothermic Instruments - mcqs, objective type question, multiple choice questions and answer 1. The chief field of application of thermal instrument is the measurement of current of frequencies.
a. Above the range of moving iron instrument
b. Below the range of moving iron instrument
c. Near the range of moving iron instrument
d. Same as the range of moving iron instrument

2. The increase in length of wire in thermal instrument is proportional to the
a. Current
b. Square of current
c. Reciprocal of current
d. Square of reciprocal of current

3. The bi-metallic instruments hive high warming up time as.....
a. 15 minutes
b. 900 seconds
c. both (a) & (b)
d. 5 minutes

4. Material for bi-metallic instruments are.
a. Copper iron
1. Platinum silver
c. Platinum iridium
d. Both (b) & (c)

5. One of the following is not the component of a thermo-couple instrument...
a. Harmonics
b. Heater element
c. Thermo-element
d. PMMC instrument

6. The important application of thermocouple instrument is.
a. Measurement of current
b. Voltage
c. Frequency
d. Both (a) & (b)

7. The upper limit of power frequency for thermocouple instruments is....
a. 50Hz
b. 100MHz
c. 100KHz
d. all of above

8. Bolometers have a......
a. Slow response
b. Medium response
c. Fast response
d. Steady response

9. For platinum resistance thermometer, the upper temperature range is
a. 100 °C
b. 1000 °C
c. 1100 °C
d. 1100 °F

10. Change in resistance due to temperature change is measured by.
a. Wheatstone bridge
b. Modified wheatstone bridge
c. Ohmmeter
d. Megger

11. For thermo-electric pyrometer the temperature of cold junction is maintain...
a. High
b. Low
c. Constant
d. All of above

12. One of the following is not the property of thermo-electric pyrometer...
a. Heavy in weight
b. Light in weight
c. Relatively cheap
d. Small in size

13. To measure the temperature of the electrical machines, the thermo-electric pyrometers are imbedded in the.
a. Field winding
b. Bearings
c. Both (a) & (b)
d. Commutators

14. The nature of the thermal radiation is .
a. Electrostatic
b. Electromagnetic
c. Travelling waves
d. All of above

15. One of the following is not the radiation receiving element...
a. Vacuum thermocouple
b. P-N diode
c. Thermopile
d. Photo-electric transducer