複選題51. A rod of 0.3 m carries a current of I = 48.0 A in the direction shown in the figure and rolls along the rails with a constant speed. A uniform magnetic field of magnitude 0.25 T is directed perpendicular to the rod and the rails. What is the force acting on the rod? (A) 3.6 N (→) (B) 2.4 N (←) (C) 1.2 N (←) (D) 3.6 N (←) (E) 1.2 N (→)