Two identical charged spheres suspended from a common point by two massless strings of lengths l, are initially at a distance  d(d<

From figure, Tcosθ=mg…..(i)Tsinθ=kq2x2……..(ii) From eqns. (i) and (ii), tanθ=kq2x2mg Since θ is small, ∴tanθ=sinθ=x2l ∴x2l=kq2x2mg⇒q2=x3mg2lk or q∝x3/2⇒dqdt∝32xdxdt=32xv. Since, dqdt= constant ∴v∝1x