Four charge particles each having charge Q=1 C are fixed at corners of base (at A, B, C and D) of a square pyramid with slant length 'a' (AP=BP=DP=PC=a=2m),a charge -Q is fixed at point P. A dipole with dipole moment p= 1 C-m is placed at centre of base and perpendicular to its plane as shown in figure. If the force on dipole due to charge particles is Ω4πε0N. The value of Ω is _________.