Fixed spelling mistake in Wien's displacement law (#2355)

* Fixed spelling mistake in Wien's displacement law

* added wikipedia link to Wien's law

Co-authored-by: Wolfgang Kerzendorf <wkerzendorf@gmail.com>

---------

Co-authored-by: Wolfgang Kerzendorf <wkerzendorf@gmail.com>

docs/physics/setup/model.ipynb

@@ -479,7 +479,7 @@
     "\n",
     "where $\\sigma_{\\mathrm{R}}$ is the Stefan-Boltzmann constant and $r_{\\mathrm{boundary\\_inner}}$ is once again the radius of the photosphere, calculated as part of the shell structure. Because of light-matter interactions, the output luminosity of the supernova will not be the same as the luminosity of the photosphere, so the photospheric temperature is updated throughout the simulation as part of the convergence process in order to match the output luminosity to the requested luminosity (see [Updating Plasma and Convergence](../update_and_conv/update_and_conv.ipynb)).\n",
     "\n",
-    "Next, TARDIS calculates the initial guess for the radiative temperature in each shell. This temperature is also updated throughout the simulation based on light-matter interactions (see once again [Updating Plasma and Convergence](../update_and_conv/update_and_conv.ipynb)). The initial guess for $T_\\mathrm{rad}$ is calculated using Wein's Law. Wein's Law states that the temperature of a blackbody is inversely proportional to the blackbody's peak wavelength. The proportionality constant, labeled $b$, is approximately $2.898*10^{-3} m*K$. In equation form,\n",
+    "Next, TARDIS calculates the initial guess for the radiative temperature in each shell. This temperature is also updated throughout the simulation based on light-matter interactions (see once again [Updating Plasma and Convergence](../update_and_conv/update_and_conv.ipynb)). The initial guess for $T_\\mathrm{rad}$ is calculated using [Wien's Law](https://en.wikipedia.org/wiki/Wien%27s_displacement_law). Wien's Law states that the temperature of a blackbody is inversely proportional to the blackbody's peak wavelength. The proportionality constant, labeled $b$, is approximately $2.898*10^{-3} m*K$. In equation form,\n",
     "\n",
     "$$T=\\frac{b}{\\lambda_\\mathrm{peak}}.$$\n",
     "\n",