What is a Wavelength?

Wavelength refers to the distance that a wave travels within a vibration period. That is, the distance between two adjacent vibration phases with a phase difference of 2 along the wave's propagation direction. The wavelength is equal to the product of the wave velocity u and the period T , that is, = u T. Waves of the same frequency travel at different speeds in different media, so the wavelengths are also different. ^[1]

Wavelength (or convertible to frequency) is an important characteristic indicator of a wave and a measure of the nature of the wave. For example: sound waves can be measured from its frequency. The audible sound waves of the human ear range from 20Hz to 20kHz, and the corresponding wavelengths range from 17m to 17mm. The visible light of the human eye ranges from the crimson 760nm wavelength to the purple 390nm wavelength.

Wavelength refers to the direction of wave propagation.

frequency

Is the number of waves passing through a given place within a certain fixed time, that is,

. Therefore by the front wavelength

Expression, we can get the relationship between wavelength and frequency as:

Speed of propagation

The unit is m / s (meter / second), frequency

The unit is Hertz (Hz)

The unit is meter. For example, if the broadcasting frequency of the first program of the Central People's Broadcasting Station is 639kHz (kilohertz), and the speed of electromagnetic waves in the air is 3 × 10 ⁸ m / s, the radio wave wavelength of this program can be calculated. For ^[3]

The relationship between electromagnetic wavelength and energy is

In the formula, E represents energy, h is Planck's constant, and c is the speed of light in vacuum, which is approximately 2.998x10 ⁸ m / s.

Electromagnetic wavelength

With frequency

The relation is

Where c is the speed of light,

Is the wavelength,

Is the frequency of the electromagnetic wave.