Question

A thermocouple produces a thermo emf of `40muV//.^(@)C`. A thermopile is made by using 150 such thermocouples. The temperature of the two junctions is `20^(@)C` and `40^(@)C` How much thermo emf generates in the thermopile

Answer 1

EMF for 1 couple `=40muV//.^(@)C` now in thermopile, thermo, couples are joined in series so emf
For 150 couples is equal to `150xx40muVV//.^(@)C=6mV//.^(@)C`
Now temperature difference is `=40-20=20^(@)C`
Now total emf for `20^(@)` temp. diff, `E=(6mV//.^(@)C)xx20^(@)C=120mV`