Thermo e.m.f. E of a Cu-Fe thermocouple varies with the temperature `theta` of the hot junction ( cold juction `0^(@)C`) as `E(muV)=12theta-0.02 theta^(2)`.
Determine:-
(a) Neutral temperature of the termocouple
(b) Temperature of inversion, assuming that cold junction is at `20^(@)C`.
(c) Value of Seebeck coefficient at neutral temperature

Explanation

(a) At neutral temperature `(dE)/(dtheta)=0` or `(d)/(dtheta)(12 theta-0.02theta^(2))=0`
or `12-0.02(2theta)=0` or `theta_(n)=(12)/(0.04)=300^(@)C`
(b) inversion temperature `theta_(1)=2theta_(n)-theta_(c)=2(300)-20=580^(@)C`
(c) At neutral temperature E is maximum so Seaback constant `(dE)/(d theta)` will be equal to zero