A cubical region of space is filled with some uniform electric and magnetic field. An electron enters the cube across one of its faces with velocity v and a positron enters via opposite face with velocity- v. At this instant, which one of the following is not correct?
A. The electric forces on both the particles cause identical acceleration.
B. The magnetic forces on both the particles cause equal acceleration.
C. Both particles gain or loose energy at the same rate.
D. The motion of the centre of mass is determined by B alone.
