Question

Consider a thermocouple made of iron and constantan. If the thermo emf's of iron and constantan against platinum are + 800 and -1700 $\mu V$ per 50${}^{o}C$ difference of temperature, then the emf developed per ${}^{o}C$ difference of temperature between the junctions will be (in $\mu V{/}^{o}C$)

• A. 200
• B. 150
• C. 100
• D. 50

Answer 1

Answer: (D)

50

Thermo emf per ${50}^{\circ }C$ of temperature difference $=(800-(-1700\left)\right)\mu V=2500\mu V$

Hence, thermo emf per ${}^{\circ }C$ of temperature difference $=\frac{2500}{50}\mu V{/}^{\circ }C$$=50\mu V{/}^{\circ }C$