The question might sound a bit strange at first so allow me to give some context. My prof has given a derivation of the magnetic flux where he used both $\Delta$ and $d$ for elementary line and surface elements. I am confused by the simultaneous usage of both infinite and finite elements, and the...
In my opinion, it isn't strictly correct to say that entropy is "randomness" or "disorder". The entropy is defined in statistical mechanics as $-k_B \sum_i p_i \log p_i$, where $k_B$ is Boltzmann's constant (which is only there to put it into physically convenient units) and $p_i$ is the probabil...
A wealth of meaningful info is contained in the above answers. However, a short and simple intuitive picture still seems missing.
The bottom line is that temperature measures the energy per degree of freedom, and hence $\frac{dQ}{T}$ measures nothing more than the number of degrees of freedom o...
It's the differential relationship between internal energy and entropy:
\begin{align}
dU &= T\,dS + \cdots \\
\frac{\partial S}{\partial U} &= \frac 1T
\end{align}
As energy is added to a system, its internal entropy changes.
Remember that the (total) entropy is
$$
S = k \ln\Omega,
$$
where $\Ome...
