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.

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Quantrex Academy · Accepted Answer

Correct answer: D. 1.04 × 10^ -5 V

From standard thermoelectric data, the Seebeck coefficients for copper and silver are

S_{Cu} = 2.76 \mu\text{V}/^{{}^{{}^{\circ}}}\text{C}

and

S_{Ag} = 2.50 \mu\text{V}/^{{}^{{}^{\circ}}}\text{C}

.

The relative Seebeck coefficient for a copper-silver thermocouple is:

S_{Cu-Ag} = S_{Cu} - S_{Ag} = 2.76 - 2.50 = 0.26 \mu\text{V}/^{{}^{{}^{\circ}}}\text{C}

The thermo-emf

E

developed for a temperature difference

\Delta T

is:

E = S_{Cu-Ag} \times \Delta T

Given the junctions are at

0^{{}^{{}^{\circ}}}\text{C}

and

40^{{}^{{}^{\circ}}}\text{C}

,

\Delta T = 40^{{}^{{}^{\circ}}}\text{C}

.

E = 0.26 \times 10^{-6} \times 40 = 10.4 \times 10^{-6} \text{ V} = 1.04 \times 10^{-5} \text{ V}

Determine the thermo-emf developed in a copper-silver thermocouple...

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