College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 12

(a) How much energy is required to cause an electron in hydrogen to move from the n = 1 state to the n = 2 state (b) If the electrons gain this energy by collision between hydrogen atoms in a high-temperature gas, find the minimum temperature of the heated hydrogen gas. The thermal energy of the heated atoms is given by 3 k B T /2, where k B is the Boltzmann constant.