Frequency

The different coloured lightwaves introduced in previous entry Wave length are just a small part of an array of electromagnetic waves, traveling through the universe.

Fig. Array of electromagnetic waves

As both figures Array of electromagnetic waves and Wave lengths of visible light show, all of these rays have got different wave lengths. Therefore they need varyingly much time to pass a complete cycle. The measure for the velocity (C) a light photon passes one cycle is the frequency.

The frequency of light is about 400-800 trillion (10¹⁵) wave crests per second. Because light - regardless its colour - has got a constant velocity results: The shorter the wave length, the higher the frequency.

In the span of time, a red light wave in figure Wave length of visible light needs to pass one cycle, a violet light wave can do twice.

Mathematically formulated:

C = λν

"Wellenlänge [λ] multipliziert mit der Frequenz [ν] ist gleich Geschwindigkeit [C]. Da die Geschwindigkeit eine feste Größe ist, muß es die Relation zwischen Frequenz [ν] und Wellenlänge [λ] auch sein.

[Wave length [λ] multiplied by frequency [ν] equals velocity [C]. Because velocity is constant, the ratio between frequency [ν] and wave length [λ] has to be as well]

The entry about wave length opens with the observation, that the wave length defines the colour of light. As shown, the wave length correlates with the frequency. Simultaneously arising thereby:

"[...] alles Licht ist die gleiche Energie und die unterschiedlichen Farben hängen von der geschwindigkeit ab, in der sich diese Energie an- und abschaltet."

[All light is of equal energy and the different colours depend on the different velocity, in which this energy is switching on and off]