Q:  At what wavelength (in nm) does this spectrum reach its peak?

          The peak occurs at a wavelength of about  

                   lambda = 600 nm

  

  Q:  In order to convert that wavelength to meters, divide by 10^9.

                               600 nm
                   lambda =   --------   =   6 x 10^(-7)  meters
                              10^9 nm/m

         


  Q:  What is the temperature of this star?

 
           Assuming that Arcturus emits light like a blackbody,
           its temperature must be

                           0.0029 meters
                 T   =   -----------------     Kelvin
                         6 x 10^(-7) meters
               

 
                     =    4833   Kelvin