Question

Please help me with the following problem.

True or false, the heat transfer rate across a plain wall is non-uniform.

I need someone to explain what is meant by non-uniform.

Thank you

Answer 1

Lees's disc ? Here's my guess ... a PLANE wall is a flat surface separating, in this case maybe, a HOT area from a COLD area. I the heat transfer is UNIFORM, then the hot surface would be at the same hot temperature all on the surface - there'd be no "hot spots", nor "cold spots". The cold area would have the same uniformity. If those conditions were met, then the rate of heat transfer, for which there's an equation - the rate of heat transfer = the coefficient of thermal conductivity of the material of the wall times the area of the wall times the temperature difference and divided by the thickness of the wall. A few standard experiments to test this out, one for GOOD heat conductors - metals/conductors, generally - and one for BAD heat conductors - non metals/insulators, generally. I think that Lees's disc is an example of a way of measuring heat transfer through a bad conductor/insulator and its basically a couple of quite large area discs with the material sandwiched between them.
I think that this answers the question, but I can never be sure (neither could Heisenberg, and he got a nobel prize in physics for saying so)
Good health to you
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Answer 2

Thanks for the medals. Any other problems, get in touch.
Bon voyage.