試題詳解

58. A metal rod is pulled to the right in a uniform magnetic field so that it accelerates at a constant accelerationon rails and forms a closed circuit with a resistor R as shown in Fig. 12. For simplicity, let us say at t = 0, the metal rod coincides with the resistor at x = O and is at rest. The distance between rails is L. Assume that there is no friction between the rod and rails. Which of the following statements is correct?

(A) The emfinduced by pulling the Uniform magnetic field Boz metal rod is proportional to t².
(B) The force required to pull the metal rod is proportional to t.
(C) The power dissipation in resistor is proportional to t³.
(D) The work done by the pulling force is proportional to t.
(E) None of the above is correct.