Stella Radiation E.2.5 & E.2.6

E.2.5 Apply the Stefan-Boltzmann law to compare the luminosities of different stars

E.2.6 State Wien's (displacement) law and apply it to explain the connection between the colour and temperature of the stars. 

Wien's displacement law states that the peak wavelength of the emission of black body is inversely proportional to the temperature. This can be expressed as:

Note that if the peak wavemength is determined then the surface temperature of the star can be determined.

 Stars that has a high surface temperature will emit radiation over the full range of visible frequencies and thus will appear white. From Wien's law, this tells us that the lower surface temperatures will emit more light of a higher wavelength and thus will appear to be red.