With the cold junction at `0^(@)C` the neutral temperature for a thermo-couple is obtained at `270^(@)C`.
The cold junction temperature is now lowered to `-10^(@)C` Obta in the
(a) neutral temperature
(b) the temperature of inversion in this case.

Explanation

When two dissimilar metals are joined together then at the junction the free electron tend to diffuse from the metal with greater electron density to the other with lower free electron density. Due to this diffusion. A potential difference is developed at the junction of the two metals called contact potential. when two junction are at same temperature then contact potential of two junction is same. But if one junction is heated up the rate of diffusion of free electrons at the two junction will change . As result of it the contact potentials at the two junctions will b ecome different and there will b e a potential difference is developed.