Can someone tell me which best describe Frequency. 1.Cycle per second 2.Hertz 3. Cycle per second Thank you for your help greatly appreciated....

could #1 be best, but #3 the worst? You have some confusion over the concept and its units. Frequency is better described as cycles per unit time. If the time is a second, it is cps or another word ( better in many cases ) Hz. Google could tell you all this and more.

Hertz is equivalent to cycles per second. So option 1 and 2 are the same. This should describe it OK for you http://en.wikipedia.org/wiki/Hertz

Your first and third options seem to differ in their font size - have you made a typing error? Leaving that aside, the answer will depend on what is meant by "describe". The SI unit of frequency is the Hertz, which can be described as a cycle per second. In the past, the unit of frequency was actually the cycle per second, but this officially became the Hertz in 1960. If this is the answer to some multiple-choice paper, you may be reduced to guessing. http://en.wikipedia.org/wiki/Hertz http://en.wikipedia.org/wiki/Cycle_per_second