Due to temperature variation along a conductor, potential variation occurs along it. This phenomenon is known as

Correct answer: (d) Thomson effect

Explanation

The Thomson effect is the evolution or absorption of heat when current flows through a single conductor that has a temperature difference along its length.

Unlike the Seebeck effect (potential difference from two dissimilar metals) or the Peltier effect (heat at a junction of two metals), Thomson involves only one material.