(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Two bodies of temperature T and T+[tex]\Delta[/tex]T respectively (where [tex]\DeltaT>0[/tex]) are brought into direct thermal contact. Use a mathematical formulation of the second law to show:

(i)Which way heat flows; is this heat flow reversible?

2. Relevant equations

2nd law of thermodynamics [tex]\int^{T+\Delta{T}}_{T}\frac{dQ}{T}dT[/tex]

3. The attempt at a solution

[tex]\int^{T+\Delta{T}}_{T}\frac{dQ}{T}dT=dQ\left[ln(T)\right]^{T+\Delta{T}}_{T}[/tex]

[tex]=dQln\left(\frac{T+\Delta{T}}{T}\right)[/tex]

heat flows from [tex]T+\Delta{T}[/tex] to T as the result is positive.

Is this right? seems as if im missing something out here, does the result being positive show the direction of heat flow? or is it always from higher temps to lower? and how do i show whether the heat flow is reversible?

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# Homework Help: Heat flow and entropy

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