If an electron changes it's orbit around the hydrogen nucleus from n=3 to n=1, what form of energy is released and what is the wavelength it possesses?

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.