1. The problem statement, all variables and given/known data The Saha equation for the hydrogen atom can be written as log(N+/N) = log(u+/u) + (5/2)logT - log(Pe) - χionӨ - 0.18 where Ө=5040/T χion is measured in electron volts (eV). Calculate the number of negative hydrogen ions (H-) in the solar photosphere relative to neutral hydrogen (H) for a temperature of T = 6,000 K and a pressure of log Pe = 2.7. 2. Relevant equations 3. The attempt at a solution log(N+/N) = log(u+/u) + (5/2)logT - log(Pe) - χionӨ - 0.18 log(N+/N) = log(2/1) + (5/2)log6000 - 2.7 - (13.6)x(5040/6000) - 0.18 log(N+/N) = 0.693 + 21.748 -2.7 - 11.42 - 0.18 log(N+/N) = 8.14 I chose to input 13.6 for χion since the ionisation energy for the hydrogen atom in the ground state is χion = 13.6eV. But apparently the correct solution should be 5x10(-7).