Temperature Measurement Multiple-choice questions…
— ANSWER THE FOLLOWING QUESTIONS —
- The most suitable device for measuring very small temperature changes is a
(a) thermopile
(b) thermocouple
© thermistor
- When two wires of different metals are twisted together and heat applied to the junction, an e.m.f. is
produced. This effect is used in a thermocouple to measure:
(a) e.m.f.
(b) temperature
© expansion
(d) heat
- A cold junction of a thermocouple is at room temperature of 15◦C. A voltmeter connected to the
thermocouple circuit indicates 10 mV. If the voltmeter is calibrated as 20◦C/mV, the temperature of
the hot source is:
(a) 185◦C
(b) 200◦C
© 35◦C
(d) 215◦C
- The e.m.f. generated by a copper–constantan thermometer is 15 mV. If the cold junction is at a temperature of 20 ◦C, the temperature of the hot junction when the sensitivity of the thermocouple is 0.03 mV/◦C is:
(a) 480◦C
(b) 520◦C
© 20.45◦C
(d) 500◦C
ANSWERS
Q1 - c
Q2 - b
Q3 - d
Q4 - b