How Light affects us
and how it affects the world
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Last Updated: Thursday, January 26, 2006 3:20 PM
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.
| 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 |
Wavelengths are 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(substances such as water or air), 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.
Here are four of the most important and interesting light colors. They are: