NEET-XII-Physics
33: Thermal and Chemical Effects of Electric Current
- #14Find 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).Ans : Difference in temperature, θ = 40°C
Emf, Ecs = acsθ + `` \frac{1}{2}``bcsθ2 ...(1)
acs = [2.76 - (-43.7) μV
= 46.46 μV/°C
bcs = [0.012 - (-0.47) μV/°C
= 0.482 μV/°C2
Putting this value in eq. (1), we get:
Ecs = 46.46 × 10-6 × 40 + `` \frac{1}{2}`` × 0.482 × 10-6 × (40)2
= 1.04 × 10-5 V
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