|
Approximate wavelength (in vacuum) and frequency ranges for the various colors |
| Color | Wavelength (nm) | Frequency (THz) |
|---|---|---|
| Red | 780 - 622 | 384 - 482 |
| Orange | 622 - 597 | 482 - 503 |
| Yellow | 597 - 577 | 503 - 520 |
| Green | 577 - 492 | 520 - 610 |
| Blue | 492 - 455 | 610 - 659 |
| Violet | 455 - 390 | 659 - 769 |
1 terahertz (THz) = 103 GHz = 106 MHz = 1012 Hz,
1 nm = 10-3 um = 10-6 mm = 10-9 m.
The
white
light is a mixture of the colors of the visible spectra.
| The electromagnetic and sound specta and their use for communication |
Wavelengths is a common way of describing light waves.
Wavelength = Speed of light in vacuum / Frequency.
The speed of light is the
velocity of electromagnetic wave in vacuum, which is 300,000 km/sec.
Light travels slower in other media, and different wavelengths travel at
different speeds in the same media. When light passes from one media to
another, it changes speed, which causes a deflection of light called
refraction. The index of refraction, n, is defined as the following
ratio:
n = Speed of light in vacuum / Speed of light in a specific medium.