When a substance gains or loses energy, its <u>temperature</u> or <u>state</u> changes. These two changes do <u>not</u> happen with respect to time; the temperature remains <u>the same</u> until the change of <u>state</u> is complete.
Explanation:
This statement is about energy and change of the state of the matter. By gaining or losing energy, the physical state of the matter can change into one another. Melting, freezing, condensation, evaporation, sublimation, and deposition are the processes that support to change the physical state of the matter. Change in state and change in the matter do not happen at the same time. A substance gains or loses energy to reach a specific temperature and remains constant until the physical change of matter is completed.
Refractive index applies to gases, liquids and some solids, but if a solid seems totally opaque then refractive index might not be an obvious property. Similarly viscosity is not obviously applicable to most solids.
