Two charges of equal magnitude q are placed in air at a distance 2 a apart and third charge -2q is placed at mid – point. The potential energy of a system is? ( ԑo = permittivity of free space ) . (MHT-CET ~ 2014)
a ] - q 2 / ( 8 π ε o a ) b] - 3 q 2 / ( 8 π ε o a )
c] – 5 q 2 / ( 8 π ε o a ) d] - 7 q 2 / ( 8 π ε o a )