A parallel plate air capacitor has capacity C, distance of separation between plates is d and potential difference V is applied between the plates. Force of attraction between the plates of the parallel plate air capacitor is

Force of attraction between the plates of the parallel plate air capacitor isF=Q22ε0Awhere Q is the charge on the capacitor, ε0 is the permittivity of free space and A is the area of each plate. But Q=CV and C=ε0Ad or ε0A=Cd ∴ F=C2V22Cd=CV22d