Question

Inversion temperature of a thermocouple depends on

• A. Cold junction temperature only.
• B. Hot junction temperature.
• C. Nature of the metals only..
• D. Both on nature of the metals and the cold junction temperature

Answer 1

The correct option is D Both on nature of the metals and the cold junction temperature

The particular temperature at which, the thermo emf becomes zero is called the inversion temperature.

On heating slightly further, the direction of the thermo emf is reversed, as the number densities of both the metals used are reversed. Therefore, the current reverses direction. This temperature depends on the temperature of the cold junction and the nature of the material.