(a) Another way to obtain the temperature of a black body is by taking the area under the Planck curve (i.e., by integrating Planck's law over all wavelengths). This area is also different for different temperatures T. Integrate Equation 2.8 over all frequencies instead of wavelengths to find the energy density (the result is still identical however the math is easier in terms of frequencies). Hint: make the following substitution x=kTh into the definite integral, 0ex1x3dx=154 b) If all goes well in (a) the final result is called the Stefan-Boltzmann Law and is of the form I=CT4. What is the value of the constant C