16. The magnitude of the magnetic field at point P, at the center of the semicircle shown below is given by: (A) μ0i/R2, (B) (μ0i/2)R, (C) μ0i/2R, (D) (μ0i/4)R, (E) μ0i/4R.
16.The magnitude of the magnetic field a..-阿摩線上測驗