Question

Find the thermo-emf developed in a copper-silver thermocouple when the junctions are kept at 0°C and 40°C. Use the data in table (33.1).

Answer 1

Difference in temperature, θ = 40°C
Emf, E_cs = a_csθ + $\frac{1}{2}$b_csθ² ...(1)
a_cs = [2.76 − (−43.7) μV
= 46.46 μV/°C
b_cs = [0.012 − (−0.47) μV/°C
= 0.482 μV/°C²
Putting this value in eq. (1), we get:
E_cs = 46.46 × 10⁻⁶ × 40 + $\frac{1}{2}$ × 0.482 × 10⁻⁶ × (40)²
= 1.04 × 10⁻⁵ V