X-Git-Url: https://hackdaworld.org/gitweb/?p=lectures%2Flatex.git;a=blobdiff_plain;f=solid_state_physics%2Ftutorial%2F2_04.tex;fp=solid_state_physics%2Ftutorial%2F2_04.tex;h=08180fb4f333a0a01b8bf1fc02bc61e7250dd2b7;hp=0000000000000000000000000000000000000000;hb=e3dace08d67225de11d0e1b0a829c8a7efafa545;hpb=cd77e3b6e7e35332d6fedd7093cc9bdb86f53277 diff --git a/solid_state_physics/tutorial/2_04.tex b/solid_state_physics/tutorial/2_04.tex new file mode 100644 index 0000000..08180fb --- /dev/null +++ b/solid_state_physics/tutorial/2_04.tex @@ -0,0 +1,102 @@ +\pdfoutput=0 +\documentclass[a4paper,11pt]{article} +\usepackage[activate]{pdfcprot} +\usepackage{verbatim} +\usepackage{a4} +\usepackage{a4wide} +\usepackage[german]{babel} +\usepackage[latin1]{inputenc} +\usepackage[T1]{fontenc} +\usepackage{amsmath} +\usepackage{ae} +\usepackage{aecompl} +\usepackage[dvips]{graphicx} +\graphicspath{{./img/}} +\usepackage{color} +\usepackage{pstricks} +\usepackage{pst-node} +\usepackage{rotating} + +\setlength{\headheight}{0mm} \setlength{\headsep}{0mm} +\setlength{\topskip}{-10mm} \setlength{\textwidth}{17cm} +\setlength{\oddsidemargin}{-10mm} +\setlength{\evensidemargin}{-10mm} \setlength{\topmargin}{-1cm} +\setlength{\textheight}{26cm} \setlength{\headsep}{0cm} + +\renewcommand{\labelenumi}{(\alph{enumi})} +\renewcommand{\labelenumii}{\arabic{enumii})} +\renewcommand{\labelenumiii}{\roman{enumiii})} + +\begin{document} + +% header +\begin{center} + {\LARGE {\bf Materials Physics II}\\} + \vspace{8pt} + Prof. B. Stritzker\\ + SS 2008\\ + \vspace{8pt} + {\Large\bf Tutorial 4} +\end{center} + +\vspace{8pt} + +\section{Legendre transformation and Maxwell relations} + +\begin{enumerate} + \item Consider the total differential + \[ + df= \sum_{i=1}^{n} u_i dx_i + \] + with the state function $f=f(x_1,\ldots,x_n)$ and its partial derivatives + $u_i=\frac{\partial f}{\partial x_i}$. + Rewrite the total differential of the function $g$ defined as + \[ + g=f-\sum_{i=r+1}^{n} u_i x_i + \] + in such a way that $g$ is immediately identified to be a function of + the variables $x_1,\ldots,x_r$ and $u_{r+1},\ldots,u_n$, + where $u_i$ is called the conjugate variable of $x_i$. + The transformation is called Legendre transformation. + \item By taking the derivatives of transformed thermodynamic potentials + with respect to the variables they depend on, + relations between intensive and extensive variables can be gained. + + Start with the internal energy $E=E(S,V)$. + Write down the total differential using the equalities + $T=\left.\frac{\partial E}{\partial S}\right|_V$ and + $-p=\left.\frac{\partial E}{\partial V}\right|_S$. + Find more relations by doing the transformation to the potentials + \begin{itemize} + \item $H=E+pV$ (Enthalpy) + \item $F=E-TS$ (Helmholtz free energy) + \item $G=H-TS=E+pV-TS$ (Gibbs free energy) + \end{itemize} + and taking the appropriate derivatives. + \item For a thermodynamic potential $\Phi(X,Y)$ the following identity + expressing the permutability of derivatives holds: + \[ + \frac{\partial^2 \Phi}{\partial X \partial Y} = + \frac{\partial^2 \Phi}{\partial Y \partial X} + \] + Derive the Maxwell relations by taking the mixed derivatives of the + potentials in (b) with respect to the variables they depend on. + Exchange the sequence of derivation and use the identities gained in (b). +\end{enumerate} + +\section{Thermal expansion of solids} + +It is well known that solids change their length $L$ and volume $V$ respectively +if there is a change in temperature $T$ or in pressure $p$ of the system. + +\begin{enumerate} + \item The coefficient of thermal expansion of a solid is given by + $\alpha_L=\frac{1}{L}\left.\frac{\partial L}{\partial T}\right|_p$. + Show that the coefficient of thermal expansion of the volume + $\alpha_V=\frac{1}{V}\left.\frac{\partial V}{\partial T}\right|_p$ + equals $3\alpha_L$ for isotropic materials. + \item + \item +\end{enumerate} + +\end{document}