Question

The temperatures of the junctions of a bismuth-silver thermocouple are maintained at 0°C and 0.001°C. Find the thermo-emf (Seebeck emf) developed. For bismuth-silver, a = − 46 × 10⁻⁶ V°C⁻¹ and b = −0.48 × 10⁻⁶ V°C⁻².

Answer 1

Given:
Difference in temperature, θ = 0.001°C,
a = − 46 × 10⁻⁶ V °C⁻¹
b = − 0.48 × 10⁻⁵ V °C⁻².
Emf, E = aθ + $\frac{1}{2}$bθ²
⇒ E = (− 46 × 10⁻⁶) × (0.001) $-\frac{1}{2}$ × (0.48 × 10⁻⁶ )× (0.001)²
= − 46 × 10⁻⁹ − 0.24 × 10⁻¹²
= − 46.0024 × 10⁻⁹
= − 4.6 × 10⁻⁸ V