11.4 Experiment of Despretz, Wiedemann and Franz for Comparison of Conductivities of Two Different Materials
In 1822, Despretz compared the thermal conductivities of two materials by heating one end of each of the rods made with the materials, and measuring temperature at three equidistant places of the rods. For this purpose three equidistant holes were made and filled with mercury in which mercury-in-glass thermometers were introduced for temperature measurement.
Let θ1, θ2, θ3 be the temperatures at distances x, x + a, x + 2a from the hot end, respectively; then from Eq.11.19, we can write
or
Putting y = eαa in Eq. 11.29, we have ...
Get Heat and Thermodynamics now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.