Question

In the Seebeck series Bi occurs first followed by Cu and Fe among other. The Sb is the last in the series. If ${\zeta }_1$ be the thermo emf at the given temperature difference for Bi - Sb thermocouple and $\zeta$, be that ofr Cu-Fe thermocouple, which of the following is true?

• A. ${\zeta }_1={\zeta }_2$
• B. ${\zeta }_1<{\zeta }_2$
• C. ${\zeta }_1>{\zeta }_2$
• D. Data is not sufficient to predict it.

Answer 1

Answer: (C)

${\zeta }_1>{\zeta }_2$

Seedback series is a series of metals arranged in a such a way that if any two of them form a thermocouple, the current would flow through the cold junction from the metal occurring earlier in the series to the metal occurring later.
Bi-Sb thermocouple will give more emf because Bi and Sb are more widely separated than Cu and Fe in the thermoelectric series. thus, ${\xi }_1>{\xi }_2$