8. A solid rod with length L, resistance..-阿摩線上測驗
8. A solid rod with length L, resistance R and mass M initially rotates with angular
velocity ω in a uniform magnetic field B. The two ends of the rod are connected by a
conducting wire without resistance. According to Lenz's Law, the induced current will
oppose the change of magnetic flux. In this case, the induced current will produce a
torque to slow down the rotation speed. What is the torque? Take the pivot point as the
origin.
(A)
(B)
(C)
(D)
(E)0