This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Thermoelectric Transducer”.
1. Thermoelectric transducer is a __________
a) temperature transducer
b) pressure transducer
c) inductive transducer
d) capacitive transducer
Explanation: A thermoelectric transducer is a temperature transducer. It converts thermal energy into electrical energy.
2. Commonly used thermoelectric transducer is
c) linear variable differential transducer
d) loud speaker
Explanation: The most commonly used thermoelectric transducer is a thermocouple. It measures the change in temperature and converts it into an electrical signal.
3. The algebraic sum of e.m.f.s in a circuit containing thermocouples is
Explanation: In a circuit consisting of many thermocouples, the algebraic sum of the e.m.f.s produced is zero. It remains constant with temperature.
4. What is a thermopile?
a) single thermocouple
b) series-parallel connection of thermocouples
c) parallel connection of thermocouples
d) series of thermocouples
Explanation: Thermopile is a series connection of thermocouples. By making use of thermopiles, a more sensitive element is obtained as compared to a single thermocouple.
5. Chromel-constantan thermopile consists of 25 thermocouples.
Explanation: A chromel-constantan thermopile provides a sensitivity of 1 mv/°F. It is made up of 25 thermocouples. Temperature variation as small as 0.001°F can be measured using this thermopile.
6. Thermocouple must provide ________
a) small thermo e.m.f
b) sufficient thermo e.m.f
c) no thermo e.m.f
d) infinite thermo e.m.f
Explanation: A thermocouple must be able to provide sufficient thermo e.m.f. This must be with respect to each degree variation in the temperature. It helps in detecting the temperature variation and in measurement.
7. Most suitable material for a thermocouple is ________
Explanation: Platinum is the most suitable material for constructing thermocouples. It has a very high sensitivity. Constantan is the other material (alloy) with a composition of 40 % of Ni and 60 % of Cu used in a thermocouple.
8. If two different metals are joined forming a closed circuit an electric current flows.
Explanation: When two different metals are joined together forming a closed circuit, if the temperatures of the two junctions are different then an electric current flows through the circuit.
9. For measuring higher temperatures using a thermocouple.
a) no wire is required
b) wire must be small
c) wire must be thin
d) wire must be heavy
Explanation: Higher temperatures can be measured using a thermocouple by making the wire heavy. Increase in size of the wire affects the response time of the thermocouple.
10. For accurate temperature measurement in a thermocouple.
a) cold compensation is needed
b) hot compensation is needed
c) no compensation is needed
d) hot and cold compensations are needed
Explanation: Temperature can be measured accurately by using a thermocouple with cold junction temperature compensation.
Sanfoundry Global Education & Learning Series – Electrical Measurements.
To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.