More wavelenght has an electromagnetic wave the minus frequency

[scientifico]

Hi,
i read the more wavelength has an electromagnetic wave the minus frequency it has, but how is possible to prove that?
what experimenst were done?

Thanks!

 

[tiny-tim]

hi scientifico!

it applies to any wave … wavelength times frequency = speed …

see eg http://en.wikipedia.org/wiki/Wavelength#Sinusoidal_waves"

(and it's not experimental, it's from the definitions)

 

[scientifico]

what exactly is the frequency of a wave?

 

[Claude Bile]

Frequency = cycles per second (units, Hz = 1/s).
Wavelength = distance between successive peaks (units, m).

Then by definition, Velocity = Wavelength x Frequency.

If velocity is constant (as in the case with EM waves), then as wavelength increases, frequency decreases and vice-versa.

Claude.

 

[Drakkith]

what exactly is the frequency of a wave?

Think of a wave in water. If there are many waves passing a certain point per second then the frequency is higher than if there are fewer waves passing that point. Wavelength is the distance between those waves. If you lower the wavelength, IE shortin it, then the frequency will increase because there are more waves. And vice versa. Amplitude is how high the waves peaks are. Look up wavelength and such on wikipedia.

 

[scientifico]

ok, thanks!
how is possible measure so exactly the light wavelength?

 

[Claude Bile]

The most common method is to shine the light on a properly calibrated dispersive element (such as a prism or grating) and measure the deflection of the beam. Commercial optical spectrum analysers (OSAs) use this principle. Alternatively, you can use a Fabry-Perot cavity and measure the transmission with respect to the reflector spacing. This method typically has higher resolution, but a lower (free) spectral range.

Claude.

 

[scientifico]

is there a why that electromagnetic waves do "up and down" in vacuum istead of simply going straight?
electromagnetic waver are only formed by electron, right?

thanks!

 

[scientifico]

is there a why that electromagnetic waves do "up and down" in vacuum istead of simply going straight?
electromagnetic waver are only formed by electron, right?

thanks!

 

[Drakkith]

is there a why that electromagnetic waves do "up and down" in vacuum istead of simply going straight?
electromagnetic waver are only formed by electron, right?

thanks!

Electromagnetic waves are Photons, not electrons. All light is an electromagnetic wave. As is all x-rays, gamma rays, microwaves, radio waves, infrared waves, ETC. The only difference in any of them is the frequency.

And you are misunderstanding how an EM wave works. It doesn't MOVE up and down, it oscillates up and down in one field, and side to side in the other field as it propegates in a direction. The overall MOVEMENT of the wave/photon is straight. Do not think of it as a particle that moves up and down in a wavelike manner as it propegates through space.

See http://en.wikipedia.org/wiki/Electromagnetic_radiation for more info.