what is physical significance of wander vaals parameters?

Starting from the ideal gas equation, you add a term to the pressure to account for the intermolecular forces and you subtract a term from the volume to account for the volume occupied by the molecules that can't be occupied by the other molecules (excluded volume)

For very dilute gases, both of these terms are negligible

The vander Waals equation is an equation of state that can be derived from a special form of the potential between a pair of molecules, It is also sometimes used as a synonym for the totality of intermolecular forces.

Also Vander Waals forces define the chemical character of many organic compounds. They also define the solubility of organic substances in polar and non-polar media.

As it is evident that Vander Waals forces include attractions between atoms, molecules, and surfaces, so the graphite is one of the allotrope of carbon and is polar it can be justified with the above.