Ebl ¼ 2phpc2
l5 exp hpc=kBlT
1 ð8:21Þ
where
Ebl ¼ total emissive power at the wavelength l
l ¼ wavelength
c ¼ speed of light in a vacuum ¼ 2.998 108 m/s
hp ¼ Planck’s constant ¼ 6:6256 1034 J s
kB ¼ Boltzmann’s constant ¼ 1:3805 1023 J=K
Figure 8.27 is a plot of this wavelength distribution for various temperatures. For the purposes of
radiative temperature measurements, it is crucial to note that the maximum energy emission shifts to
shorter wavelengths at higher temperatures. Our experiences confirm this behavior through
observation of color changes as a surface is heated.