The vector potential for an almost point like magnetic dipole located at the origin is sin - where (r,0,0) denote the spherical polar coordinates and is the unit vector A= 4r along. A particle of mass m and charge q, moving in the equatorial plane of the dipole, starts at time =t=0 with an initial speed , and an impact parameter b. Its instantaneous speed at the point of closest approach is (a) Vo (b) 0/0 4mb (c) vo + Scanned with OKEN Scanner (d) + ( 4mb