Two charges, each equal to q, are kept at \[x=-a\] and\[x=a\] on the x−axis. A particle of mass m and charge\[{{q}_{0}}=\frac{q}{2}\] is placed at the origin. If charge\[{{q}_{0}}\]is given a small displacement\[(y<<a)\] along the y−axis, the net force acting on the particle is proportional to:
AIEEE Solevd Paper-2013