[单选题]
Suppose that you wish to construct a simple A+ahd.ybexw( ,-emp5a C generator with an oqdl e:hs;-sjfdxe48 ;wsv,p2utput of 12 V maximum when rotated at 60 Hz. A magnetic field:de 4sdjh,fe-wqv8l2 x ps;; s of 0.050 T is available. If the area of the rotating coil is $100 \; cm^{2}$, how many turns are needed?
