1. What is the cause of electric current in thermoelectricity?
Ans: Due to the difference of temperature of two junction, thermoemf is set up in the junction. This causes the electrons of the thermocouple to drift and electric current is generated.
2. What is thermocouple?
Ans: When a loop is formed by the pair of metal kept at different temperature for the production of thermoelectricity, then the pair of metal is called thermocouple.
4. Why Sb-Bi thermocouple is preferred other thermocouples?
Ans: We know Sb is the first element in thermoelectric series while Bi is the last element of thermoelectric series. The emf developed will be more if there is larger separation between the chosen metals from thermoelectric series. So, antimony-bismuth thermocouple is considered best for the generation of thermoelectricity.
3. What are the factors on which thermoelectric emf depends upon?
Ans: The factors on which thermoelectric emf depend on are:
- Type of thermocouple used.
- Temperature difference between the two junctions.
5. What is neutral temperature and temperature of inversion?
The temperature at which there is a generation of maximum emf is called neutral temperature. The temperature at which the generation of thermo emf is zero is called temperature of inversion.
6. What do you mean by Peltier effect?
Ans: When current is passed through a thermo-couple, heat will evolve at one junction and absorbed at other junction. Thus one junction becomes hot and other junction becomes cold. This effect is called Peltier’s effect.
7. Does the thermoelectric effect obeys laws of conservation of energy?
Ans: Yes. The generation of thermoemf in a thermocouple is the result of conversion of net heat absorbed in the thermocouple to electrical energy. So, it obeys the laws of conservation of energy.