a. Which states of a hydrogen atom can be excited by a collision with an electron with kinetic energy \(K=12.5 \mathrm{eV}\) ? Explain.

b. After the collision the atom is not in its ground state. What happens to the electron? (i) It bounces off with \(K>12.5 \mathrm{eV}\), (ii) It bounces off with \(K=12.5 \mathrm{eV}\), (iii) It bounces off with \(K<12.5 \mathrm{eV}\), (iv) It is absorbed by the atom. Explain your choice.

c. After the collision, the atom emits a photon. List all the possible \(n \rightarrow m\) transitions that might occur as a result of this collision.