\documentclass[tikz,crop,convert={outfile=\jobname.svg}]{standalone}
\usetikzlibrary{decorations.pathmorphing}
\begin{document}
\begin{tikzpicture}
\draw [
line join=round,
decorate, decoration={
    zigzag,
    segment length=4,
    amplitude=.9,post=lineto,
    post length=2pt
}]  (-2,0) -- (2,0);
\draw (-2,0) .. controls (-1,2) and (1,2) .. (2,0);
\filldraw [black] (-2,0) circle (2pt) node[anchor=north] {\(-l/2\)};
\filldraw [black] (2,0) circle (2pt) node[anchor=north] {\(l/2\)};
\draw (0,0) node [anchor=south] {1};
\end{tikzpicture}
\end{document}