試題詳解

3.A charged particle at rest is released in a region of uniform electric field in the y direction and uniform magnetic field in the z direction. Which of the following statements is not correct?
(A) The motion of the particle in the y direction is periodic.
(B) In average, the particle moves with a constant speed in the x direction.
(C) The kinetic energy of the particle increases with time.
(D) The magnetic field does no work on the particle.