On adding heat to a molecule, atoms start bouncing back and forth and repeat the motion that are known as the vibrations.
Answer: Option B
Explanation:
We often see telephone wires getting expanded and hung up lower in the hot summer days while they are much more contracted during the winter times. This is because of the molecular expansion as when the atoms of the molecules gain sufficient energy, they start vibrating back and forth from their median position and start expanding their vibration spaces.
Due to this, the molecular structure of the object also expand and hence the object. On the other hand, when heat is extracted from the object to the outer atmosphere, atoms contract in their spaces of vibrations and hence, the molecular structure also contract. This means, the object contract or shrink from their original size and structure when heat is extracted from them.