(A) Use two lines of the Paschen series of hydrogen, along with the general curve of growth of the Sun, to calculate the number of hydrogen atoms with electrons in the n = 3 orbital above each square metre of the Sun's surface. The Paschen series results from an electron making an upward transition from the n = 3 orbital of the hydrogen atom. (B) Then use the Bolztmann and Saha equations to calculate the total number of hydrogen atoms above each square metre of the Sun's surface.
For more information on how to do this problem, and for tables of relevant data, see
www.canismajor.ca.