Question

A solid expands upon heating because.

• A. The potential energy of interaction between atoms in the solid is asymmetric about the equilibrium positions of atoms
• B. The frequency of vibration of the atoms increases
• C. The heating generates a thermal gradient between opposite sides
• D. A fluid called the caloric flows into the interatomic spacing of the solid during heating thereby expanding it

Answer 1

The correct option is A The potential energy of interaction between atoms in the solid is asymmetric about the equilibrium positions of atoms

As the potential energy is asymmetric about the equilibrium position of the atoms, as the temperature increases, the average separation between the atoms (green dots) increases. Thus, the solids expand on heating.