is it only the thermal kinetic energy of electrons that cause seeback effect..if it were so then why do we join two different metals to form the junctions that are kept at different temperatures??

Question

anonymous · Answer

why do we join two "different" metals to form the junctions that are kept at different temperatures in thermocouple???

anonymous · Answer

hi shaske!! u r pic is of his well it looks u watch naruto !! well coming to the point u r ans... is
do u know what's TKE if yes then look to the meaning of seeback effect i.e. The creation of an electrical potential across points in a metal that are at different temperatures. The effect is caused by the thermal energy of the valence electrons in the warmer part of the metal; the kinetic energy of these electrons, which are very free in metals, allows them to migrate toward the colder part more readily than the colder electrons migrate to the warmer part. The colder part of the metal is therefore more negatively charged than the warmer part, resulting in electric potential. The Seebeck effect is used in thermocouples. It was discovered by the German physicist Thomas Seebeck (1770-1831).

anonymous · Answer

hey,its itachi!!!
thanks but that's exactly what i've seen everywhere else.
Now if this were so then....
After some time some electrons will flow from hot end to cold end making hot end positive and hence at high potential.
Soon this building of potential should stop the current flow as the warm end will become too positive to let electrons escape anymore to cold end and thus the current flow should stop after some time..
i guess this is not observed..also to complete circuit two different metals are joined and the joined ends are kept at hot and cold temp.
why are two DIFFERENT metals used?