Excited States State of equilibrium, state of lowest energy, is known as the ground state Higher energy states are known as excited states .
Light is emitted when atom relaxes to ground state from excited state.
On careful examination, we find that light emitted by excited atoms has discrete values of energy. Deduce that electrons in an atom have discrete values of energy. Energy levels of electrons in an atom are quantized. The electron-volt is the change of energy experienced by an electron when it is relocated from one point to another, when the two points have a 1.0 V difference. Copyright George Watson, Univ. of Delaware, 1999.