A cylindrical region of uniform magnetic field exists perpendicular to plane of paper which is increasing at a constant rate The diameter of cylindrical region is l. A non-contucting rigid rod of length l having two charged particles is kept fixed on the diameter of cylindrical region w.r.t. inertial frame. If two charged particles having charges q each is kept fix at the ends of the non-conducting rod. The net force on any one of the charge is