19. John presents a wedding ring to Mary. To impress her, he spins the ring about a vertical axis at a frequency of 60 Hz in a magnetic field of B = 0.5 T as shown. If the area of the ring is 2.0 × 10⁻⁴ m², calculate the maximum emf induced in the ring.


(A) 0.038 V
(B) 0.046 V
(C) 0.052 V
(D) 0.060 V
(E) not enough information

答案：登入後查看
統計： 尚無統計資料