Please explain this point of physisorption.

Dear Student, When the accumulation or adsorption of gas on the surface of a solid occurs on account of weak Van der Waal’s forces, then it is known as the Physical Adsorption or Physisorption. In physical adsorption occurs due to inter-molecular attractive forces between the adsorbate and adsorbent.If the size of adsorbent pores is close to the size of adsorbate molecules, multilayer adsorption takes place i.e adsorption takes place until all the pores are filled with adsorbate molecules. Regards