Final answer:
Electron transitions to lower energy states, after an interaction with another electron, release energy typically in the form of a photon. This transition is quantized and contributes to the characteristic emission spectra of atoms.
Step-by-step explanation:
When an electron accidentally knocks into another electron and falls into a lower energy orbital, the process is called a transition to a lower energy state or 'relaxation'. Electrons exist in specific energy levels or orbitals around an atom's nucleus, with each level having a defined energy. Electrons always seek the lowest energy state, known as the ground state. If an electron absorbs energy, for example from a photon, it can jump to a higher energy level or excited state. When it then falls back to a lower energy level, energy is released, often as a photon.
The energy change associated with this transition is quantized, which means it can only occur in specific amounts. These energy changes give rise to the characteristic emission spectra of elements. According to the Bohr model of the atom, each electron moves in a fixed orbit and transitions between these orbits result in the absorption or emission of specific quanta of energy.