Concepts Of Physics MCQ Edition [Volume 2]PhysicsThermal and Chemical Effects of Electric Current
Determine the thermo-emf developed in a copper-silver thermocouple if the junctions are maintained at 0^ C and 40^ C . Use the data from the table.
Options
- A1.04 10⁻⁴ V
- B5.20 10⁻⁶ V
- C2.08 10⁻⁵ V
- D1.04 10⁻⁵ V
Correct answer
D. 1.04 10⁻⁵ V
Step-by-step solution
From standard thermoelectric data, the Seebeck coefficients for copper and silver are S_ Cu = 2.76 V /^ C and S_ Ag = 2.50 V /^ C . The relative Seebeck coefficient for a copper-silver thermocouple is: S_ Cu-Ag = S_ Cu - S_ Ag = 2.76 - 2.50 = 0.26 V /^ C The thermo-emf E developed for a temperature difference T is: E = S_ Cu-Ag T Given the junctions are at 0^ C and 40^ C , T = 40^ C . E = 0.26 10⁻⁶ 40 = 10.4 10⁻⁶ V = 1.04 10⁻⁵ V