How can light be produced in an atom

Question

science question 

Answer 1

A stable atom has certain allowed energy states.  An atom can absorb energy from radiation or a collision.  If the amount of absorbed energy is just right, an electron in the atom can jump into a higher energy state.  That state is unstable, and the electron will jump back down to a lower, more stable energy state.  In the process of the electron jumping down, the atom emits a photon of light with energy equal to the difference in energies between the higher and lower energy sates.