Q:  What are the units of specific intensity?


       The units must be (in MKS)

 
                  Joules
           -----------------------
            s * m^2 * m * sr

       
       where the "m^2" refers to the area of the plate (dA), and the
       next term "m" refers to the range of wavelengths (d lambda).
 
       We can combine these terms to yield


                  Joules                          ergs
           -----------------------   or     -----------------
                s * m^3 * sr                 s * (cm)^3 * sr