click to view
The frequency of light is the number of peaks that pass by a given point in space per second. For all waves, this depends on both the speed and the wavelength. The relationship for light is
\[c = \lambda \nu \]
where c is the speed of light, \(\lambda\) is the wavelength and \(\nu\) is the frequency. Since speed has units of distant per time, and wavelength has units of distance, frequency has units of inverse time. We will use units of inverse seconds which are typically called Hertz, abbreviated as Hz.
The small simulator below graphically shows the relationship between the frequency and the wavelength (note: it is not to scale as the wavelengths are changing over many orders of magnitude).
click to view