PERIOD, FREQUENCY, WAVELENGTH, AND PROPAGATION SPEED

Sometimes it’s easier to talk about a wave’s period rather than its frequency. The period T (in seconds) of a sine wave is the reciprocal of the frequency f (in hertz). Mathematically, the following formulas hold:
f = 1/T = T^-1
T = 1/f = f^-1
If a wave has a frequency of 1 Hz, its period is 1 s. If the frequency is one cycle per minute (1/60 Hz), the period is 60 s. If the frequency is one cycle per hour (1⁄3600 Hz), the period is 3,600 s, or 60 min.
The period of a wave is related to the wavelength λ(in meters) and the propagation speed c (in meters per second) as follows: Wavelength equals speed times period. Mathematically:
λ = cT
This gives rise to other formulas:
λ = c/f
c = fλ
c = λ/T