Question

How do I go about finding the frequency of an AC circuit given the time, voltage and resistance?

Answer 1

I think you need more information than what you're providing.

Answer 2

If you have the time for the AC wave to complete a cycle then you can apply the relationship below;

\[T = 1/f\] ....where T is the time to complete a 1 cycle or the "period" of the AC wave & f is the frequency of the waveform.

Enjoy