Final answer:
The word 'agitation' refers to thermal motion of atoms and molecules, causing them to emit and absorb radiation; it generally indicates a state of nervousness or disturbance. In the context of waves, a disturbance is an oscillation caused by energy.
Step-by-step explanation:
The meaning of the word agitation in the passage you provided relates to the concept of thermal agitation which is the thermal motion of atoms and molecules in any object at a temperature above absolute zero. This thermal motion causes the atoms and molecules to emit and absorb radiation. In a more general sense, outside the context of physical sciences, 'agitation' can often mean a state of nervousness or unrest, or the action of briskly stirring or disturbing something, such as when someone agitates water in a tub or when people are agitated in a crowd<\/p>
When considering the context of waves, a disturbance, as mentioned with reference to waves, refers to an oscillation that is produced by some form of energy. It is not necessarily related to agitation, but both terms involve some form of movement or unrest.<\/p>