Home Home Stories Stories Library Library Links Links
News News Search Search Forum Forum Shop Shop

 
 Print   Mail
this article
 
 » Sitemap
TVOX Stories
 
Wavelength
 
 

The wavelength is the distance between repeating units of a wave pattern. It is commonly designated by the Greek letter lambda (λ).


Wavelength


The x axis represents distance, and I would be some varying quantity (for instance air pressure for a sound wave or strength of the electric or magnetic field for light), at a given point in time as a function of x.

Wavelength λ has an inverse relationship to frequency f, the number of peaks to pass a point in a given time. The wavelength is equal to the speed of the wave type divided by the frequency of the wave. When dealing with electromagnetic radiation in a vacuum, this speed is the speed of light c, for signals (waves) in air, this is the speed of sound in air. The relationship is given by:


Wavelength λ inverse relationship to frequency f


where:

λ = wavelength of a sound wave or electromagnetic wave

c = speed of light in vacuum = 299,792.458 km/s ~ 300 000 km/s = 300,000,000 m/s or

c = speed of sound in air = 343 m/s at 20 C (68 F)

f = frequency of the wave

For radio waves this relationship is approximated with the formula: wavelength (in metres) = 300 / frequency (in megahertz).

When light waves (and other electromagnetic waves) enter a medium, their wavelength is reduced by a factor equal to the refractive index n of the medium but the frequency of the wave is unchanged. The wavelength of the wave in the medium, λ' is given by:


Wavelength of the wave in the medium


where:

λ0 is the vacuum wavelength of the wave

Wavelengths of electromagnetic radiation, no matter what medium they are travelling through, are usually quoted in terms of the vacuum wavelength, although this is not always explicitly stated.

Louis-Victor de Broglie discovered that all particles with momentum have a wavelength associated with their quantum mechanical wavefunction, called the de Broglie wavelength.

[This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article: Wavelength.]



 

Comment List

There are no comments.
 
 
Copyright 2001-2006 © Valerio Saggini. - Privacy Policy - Feedback