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A thermocouple is made from two metals, Antimony and Bismuth. If one junction of the couple is kept hot and the other is kept cold, then, an electric current will

1. flow from Antimony to Bismuth at the hot junction
2. flow from Bismuth to Antimony at the cold junction
3. now flow through the thermocouple
4. flow from Antimony to Bismuth at the cold junction

Correct answer: flow from Antimony to Bismuth at the cold junction

Solution

In a thermocouple, the flow of electric current is determined by the temperature difference between the two junctions. When one junction is hot and the other is cold, the current flows from the metal with a higher thermoelectric potential (Antimony) to the one with a lower potential (Bismuth) at the cold junction.

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