1. The problem statement, all variables and given/known data Calculate the numerical value of the energy difference between the 2P 3/2and the 2P 1/2 states in Hydrogen (the fine structure). 2. Relevant equations possible relevant equations are in the attachement 3. The attempt at a solution It is quite unclear weather the relativistic (sexcond)or ,the equation which takes into account the magnetic field corrections (the first equation )of the proton around the electron has to be used.it seems that we should use the first equation. The graph on the attachement tells us which values i have to substitute. I would like someone who specialises in atomic physics ,to tell me if im thinking correctly in order to solve the problem.im very uncertain about if this answer is correct.