Question

supplemation occurs only when the solid is heated why ​

Answer 1

Answer:

this is because Sublimation intrinsically involves phase change, so there must be an input of heat of fusion & heat of vaporization. That said, a small amount of sublimation will occur in some solids (water ice for example) even when no additional heat is being added, by virtue of random energy transfer (vibration) by which a molecule of the solid receives energy from the motion of its neighbors, sufficient to break crystal bonds and vanderWaals forces and change phase to vapor, leaving the general mass commensurately cooler. This phenomenon explains the presence of water vapor pressure over ice in a situation where you place some ice at sub-freezing temperature into a zero humidity enclosure and allow equilibration.