When the hot and cold junctions of a thermocouple are interchanged, the thermo- emf:
Correct answer: D. changes the sign
- A. becomes zero
- B. doubles
- C. remain the same
- D. changes the sign
Explanation
When the hot and cold junctions of a thermocouple are interchanged, the thermo-electromotive force (EMF) changes sign. This means that if the EMF was initially positive, it will become negative, and vice versa. The magnitude of the EMF remains the same, but the direction of the current flow is reversed due to the change in the temperature gradient direction. So, the correct answer is that the thermo-EMF changes sign.
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Steady current is the continuous flow of charge at a constant rate through a conductor. The topic covers current, charge, potential difference, resistance, Ohm's law, resistivity and electrical power, along with series and parallel circuits, while distinguishing conventional current direction from electron motion.
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