10 question-answer on Thermoelectricity
1. Which of the following thermocouple produces the maximum thermo e.m.f. for the same temperature difference between hot and cold junctions?
(a) Copper-bismuth
(b) Antimony-bismuth
(c) Iron-nickel
(d) Copper-iron.
Ans: (b)
2. When a number of thermocouples are joined in series, the thermo e.m.f.
(a) Is decreased
(b) Is increased
(c) Becomes zero
(d) Remains same.
Ans: ( b)
3. If one junction of a thermocouple is heated and other junction is cooled continuously in the same steps, the e.m.f. will
(a) Increase and then decrease
(b) Increase then decrease and finally reverse
(c) No change at all
(d) Change appreciably.
Ans: (b)
4. Inversion temperature of a thermocouple is that temperature of hot junction at which the emf is
(a) Maximum
(b) Minimum
(c) Zero
(d) None of these
Ans: (c)
5. Thermocouple is an arrangement of two different metals to convert
(a) Heat energy in to electrical energy
(b) Electrical energy into chemical energy
(c) Electrical energy into heat energy
(d) Heat energy into chemical energy
Ans: ( a)
6. The temperature of the thermocouple, which is independent of the temperature of cold junction is called:
(a) Zero temperature
(b) Neutral temperature
(c) Temperature of inversion
(d) None of these.
Ans: ( b)
7. At neutral temperature, thermoelectric power is :
(a) Infinite
(b) Zero
(c) Minimum
(d) Maximum.
Ans: (b)
8. Amount of energy absorbed or evolved when 1 A of current passes for one second through a junction of two metals is called
(a) Peltier coefficient
(b) Thermo e.m.f.
(c) Thomson coefficient
(d) Thermoelectric power
Ans: (a)
9. Charge carriers in the thermo-couple are:
(a) Electrons
(b) Protons
(c) +ve ions
(d) –ve ions.
Ans: (a)
10. The thermocouple cannot act as:
(a) Thermometer
(b) A.c. generator
(c) Voltmeter
(d) Refrigerator
Ans: ( b)