Question

A thermocouple is made of iron and constantan thermo emfs of iron and constantan against platinum are 1500 $\mu$V and - 3200$\mu$V per 1000C temperature difference between the junctions,then emf developed per $1^{0}C$ difference of temperature between the junctions made of iron and constantan is

• A. $17\mu V{/}^{0}C$
• B. $4700\mu V{/}^{0}C$
• C. $4.7\mu V{/}^{0}C$
• D. $470\mu V{/}^{0}C$

Answer 1

Answer: (C)

$4.7\mu V{/}^{0}C$

Here the seebeck coefficient $\alpha =(1500+3200)/1000=4.7\mu V{/}^{o}C$
Thermo emf, $\epsilon =\alpha \Delta T$
Thermo emf developed by per ${}^{o}C=\frac{\epsilon }{\Delta T}=\alpha =4.7\mu V{/}^{o}C$