The universal wave equation is

`v = f lambda`.

- propagation speed (`v`)
- the speed of the wave, measured in metres per second (m/s)
- frequency (`f`)
- the number of cycles completed in one second, measured in hertz (Hz)
- wavelength (`lambda`)
- the length of one cycle in the wave, measured in metres (m)

We also have a few other equations for dealing with period:

`f = N/(Delta t) qquad and qquad T = (Delta t)/N qquad and qquad f = 1/T`.

- number of cycles (`N`)
- the number of cycles completed during a time interval (unitless)
- time interval (`Delta t`)
- a specific duration of time, measured in seconds (s)
- period (`T`)
- the time it takes for one cycle to be completed, measured in seconds (s); wavelength is the spatial length, period is the temporal length