The lines in an element's atomic spectrum result from electron spins going in opposite directions.

energy that is spread out among an atom's electrons.

electrons moving from a lower to a higher energy level.

electrons moving from a higher to a lower energy level.

The human eye contains a molecule called 11-cis-retinal that changes shape when struck with light of sufficient energy. the change in shape triggers a series of events that results in an electrical signal being sent to the brain that results in vision. the minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kj/mol.