Question

When the cold junction is at $0^{0}C$ and the hot junction is below the temperature of inversion, emfs developed by Sb - Pb and Pb - Bi thermocouples are 31 $\mu$V and 69 $\mu$V per degree centigrade respectively. Thermo emf developed by Bi-Sb thermocouple per ${}^{0}C$ is

• A. $100\mu V{/}^{0}C$
• B. $38\mu V{/}^{0}C$
• C. $31\mu V{/}^{0}C$
• D. $69\mu V{/}^{0}C$

Answer 1

The correct option is A $100\mu V{/}^{0}C$

Here the seebeck coefficient $\alpha =(31+69)=100\mu V{/}^{o}C$
Thermo emf, $\epsilon =\alpha \Delta T$
Thermo emf developed by per ${}^{o}C=\frac{\epsilon }{\Delta T}=\alpha =100\mu V{/}^{o}C$