Review. The energy required to excite an atom is on the order of 1 eV. As the temperature of the Uni

Review. The energy required to excite an atom is on the order of 1 eV. As the temperature of the Universe dropped below a threshold, neutral atoms could form from plasma and the Universe became transparent. Use the Boltzmann distribution function to find the order of magnitude of the threshold temperature at which 1.00 of a population of photons has energy greater than 1.00 eV.