A bottle contains a gas with atoms whose lowest four energy levels are −12eV, −6eV, −3eV, and −2eV. Electrons run through the bottle and excite the atoms so that at all times there are large numbers...

A bottle contains a gas with atoms whose lowest four energy levels are −12eV, −6eV, −3eV, and −2eV. Electrons run

through the bottle and excite the atoms so that at all times there are large numbers of atoms in each of these four energy

levels, but there are no atoms in higher energy levels. List the energies of the photons that will be emitted by the gas.

Next the electron beam is turned off, and all the atoms are in the ground state. Light containing a continuous spectrum of

photon energies from 0.5 eV to 15 eV shines through the bottle. A photon detector on the other side of the bottle shows that

some photon energies are depleted in the spectrum (“dark lines”). What are the energies of the missing photons?