Question

The emf of the battery in a thermocouple is doubled. The rate of heat generation at one of the junctions will

• A. remains unchanged.
• B. becomes half.
• C. becomes double.
• D. becomes four times.

Answer 1

Answer: (C)

becomes double.

According to Thomson effect, if the potential applied to the ends of a conductor differs, the temperature difference will develop across the two ends of conductor.
$\Rightarrow (V_2-V_1)\propto ({\theta }_2-{\theta }_1)$
$\Rightarrow dV\propto d\theta$
Hence, if the emf of the battery in a thermocouple is doubled, the rate of heat generation at one of the junctions will become double.