A rectangular coil of N turns and of length a and width b is rotated at frequency f in a uniform magnetic field of magnitude B, as indicated in the figure. The coil is connected to co-rotating cylinders, against which metal brushes slide to make contact. The emf induced in the coil is given (as a function of time t) by E = 2nfNabBsin(2nft) = Eosin(2nft). This is the principle of the commercial alternating-current generator. What value of Nab gives an emf with en = 127 V when the loop is rotated at 75.3 rev/s in a uniform magnetic field of 0.673 T? Sliding contacts- RX X X X x x x x x Number Units the tolerance is +/-2%