lf in a transformer, 'PM' denotes the maximum value of the flux, 'f' is the frequency of the supply voltage, 'N1' is number of primary winding turns, 'E1' is RMS value of the primary induced emf, then one of the equations of the transformer would be:
1
E1 = 4.44 f PM N1
2
E1 = 2.35 f PM N1
3
E1 = 1.23 f PM N1
4
E1 = 7.8 f PM N1