Why thermoelectric emf first increase with temperature and then decreases, becomes zero and then reverses its

Question

Why thermoelectric emf first increase with temperature and then decreases, becomes zero and then reverses its

Answer 1

The magnitude of the thermoelectric emf depends upon the temperatures of the hot and cold junctions.(Thermoelectric emf is the emf produced when two dissimilar metals are maintained at two different temp-hot & cold junctions)

the thermo emf increases with increasing temp and then gradually decreases. the temp of the cold junction is kept constant & only the temp of the hot junction is increased. the emf increases & becomes maximum at a temp called neutral temp. then it gradually decreases & becomes zero at a temp called temperature of inversion. beyond the temp of inversion, the emf changes sign & icreases again.

I think that this is due to the expression,

V=alpha*theta + 1/2*beta*square of theta

Not really sure

Hope i've helped u... sorry if i havn't:)