The population distribution for different energy levels follows the Boltzmann distribution law when the atoms are in the thermal dynamic equilibrium. The number of atoms at an excited state with energy level En is given by N = N(gn/g1)exp[-(En-E1)/kT]. N is the number of the atoms at the state with energy level E. k is the Boltzmann constant. gn and g are the statistical weight factors of energy level E and E. At 20 degrees centigrade and one atmospheric pressure, for pure Hydrogen atomic gas in a bottle, how much volume is needed if you can have one H atom at the first excited state? Given g=2 for the ground state and g2=8 for the first excited state for H atom.