Frequency:



Define:

The frequency of a wave is how often a particle in the wave oscillates while passing through a medium. Frequency is how often something occurs. If a particle in a wave oscillates 5 times a second, the wave's frequency is 5 cycles/second, or 5 hertz. 5 cycles occur every 1 second.

Units:

Hertz (Hz)
One Hz = 1 cycle/second.

Examples:

A particle in a wave completes 10 cycles in 1 second.
The period of the wave is 0.1 seconds. What is the frequency of the wave?
f = 1 / T
f = 1 / 0.1
f = 10
The frequency of the wave is 10 Hz.

Equations:

f = frequency
T = period
f = 1 / T
T = 1 / f

Unlike period, frequency is..........

Frequency is how often the wave passes a certain point in one second. Period is how many seconds it takes for the wave to pass a certain point. Frequency is how often something happens, and period is how long it takes for something to happen. A wave with a frequency of 10 Hz has a period of 0.1 because the time it takes to complete one cycle is 0.1 seconds.

Source:

http://www.glenbrook.k12.il.us/gbssci/phys/Class/waves/u10l2b.html
http://scienceworld.wolfram.com/physics/Frequency.html