What is the thermal emf?

Answer 1

when 2 different cpnducting materials r brought together and given a supply, there exist a potential difference between the 2.since these are 2 differt materials and an emf will be induced which is called thermo emf

Answer 2

when the two ends of conductor are at different temperature then, a small quantity of current is flow ,because at the high temperature end, the heat energy is able to excit the electron that's called "SEE BACK effect" so the excited electron is free and easily move to the other end.shortly we say that a small voltage difference is created which is called thermal emf.