Consider a coil rotating at a speed of N rpm in the field of P poles. As the coil moves past successive north the south poles, one complete cycle is generated. What is the frequency of the generated voltage?

1. \(\frac{{PN}}{{60}}\)

2. \(\frac{{PN}}{{120}}\)

3. \(\frac{{120\;P}}{N}\)

4. \(\frac{{120\;f}}{P}\)