Which of the following statements is NOT correct about generation of alternating voltage?

The correct answer is option 2.

Option 1: The number of cycles per second made by voltage induced in the armature is the frequency of the generator. If the armature rotates at a speed of 50 revolutions per second, the generated voltage will be 50 cycles per second. The accepted term for cycles per second is hertz.

Option 2: An AC generator produces one cycle per revolution for each pair of poles. A two-pole generator would complete one cycle per revolution and a four-pole generator would complete two cycles per revolution.

Option 3: The magnetic field produced by the stator poles induces a voltage in the rotor (or armature) coils when the generator is rotated. This induced voltage is represented by a voltage source. 

Option 4: Frequency, \(f={P\times N\over 120}\). The frequency is proportional to the number of poles. So, the increase in the number of poles increases the frequency.