Question

What is Variation of Thermo-Emf with Temperature?

Answer

Variation of Thermo-Emf with Temperature - In a thermocouple as the temperature of the hot junction at constant temperature (say 0° C), the thermo-emf increase till it becomes maximum at a certain temperature. (i) Thermoelectric emf is given by the equation E = αt + 1/2βt² i.e. α + βt_n = 0 ⇒ -α/β (ii) Neutral temperature is independent of the temperature of cold junction, (iii) Relation between t_n, t_i and t_c is t_n = t_i + t_c/2, (iv) At neutral temperature, thermoelectric power is zero.