How many cycles per revolution would be developed from a single loop rotating in a fourth pole AC generator?

• A. 1
• B. 3
• C. 2
• D. 4

Answer: (C)

In a fourth pole AC generator, the configuration creates multiple magnetic poles that interact with the rotor. The key factor here is understanding how the rotational motion of the loop translates into cycles of voltage generation based on the number of poles.

For every complete revolution of the loop, each pole generates a waveform of voltage. In a typical AC generator, the relationship between the number of poles and the cycles produced is clearly defined. With a configuration involving four poles, when a single loop rotates once, it effectively passes each pole twice, leading to the production of two complete cycles of alternating current. This transition happens because as the loop moves through each magnetic pole's field, it generates an alternating voltage reversal with each passage.

Thus, with one loop and four poles, the system produces two cycles of voltage per revolution, making it possible to determine output frequency based on the generator's speed. This illustrates how the principles of electromagnetism apply within the context of generator design, specifically leading to the correct answer being two cycles per revolution.