In both chemisorption and physisorption, the interaction energy is negative. A more negative value indicate a stronger binding. Which means that the energies in chemisorbed systems are more negative than those of physisorption given the nature of interaction. However, a positive value means that adsorption will not occur spontaneously.

I agree with Youssef.

As far as I remember physisorption has an activation energy about -20 kJ/mol (maybe between -10 till -50), while chemisorption hat an activation energy beyond -200 kJ/mol.