For this problem you will need to write a $C$ program to generate a data file and

write a GNUPlot script to generate the graph.

According to Planck's law of black$-$body radiation, the spectral energy density $R$ as

a function of wavelength $($in metres$)$ and temperature $T($in degrees Kelvin$)$ is

given by:

$R=\frac{2c^{2}h}{{}^5}\frac{1}{e^{h\frac{c}{}KT}-1}$

where $c=3{10}^8\frac{m}{s}$ is the speed of light, $h=6\mathrm{.}626{10}^{-34}J-$s is the Planck

constant, and $k=1\mathrm{.}38{10}^{-23}\frac{J}{K}$ is the Boltzmann constant. Make a plot

$($example shown below$)$ that contains plots of $R$ as a function of $$ for values

between $0\mathrm{.}1$ and $3m$ for three temperatures $T=3000K,T=4000K,$ and $T=$

$5000K.$ Show everything on the same figure. Use different colours and$/$or line

styles for the three lines, label the axes and add a legend $($key$).$