What is light: The wavelength of light that can be dist […]
What is light:
The wavelength of light that can be distinguished by the naked eye of normal people is the wavelength between infrared and ultraviolet light, which is between 450mm and 750mm. Natural light (daylight) contains light of all wavelengths, that is, all light that is visible to the naked eye and unrecognizable to the naked eye. Because different wavelengths of light, when the speed is different from the angle through the interface (such as glass or water beads), the sunlight can be reflected in red, orange, yellow, green, blue, enamel, purple and seven different colors of visible light. Line, this is the reason why the rainbow is common in our daily life. It can be seen that the light that is uniformly mixed together with all the colors of light is white light. The proportion of the various rays of light in the sun is as large as equal, but the sunlight at different latitudes is different. Due to the relationship between the thickness of the atmosphere and the refraction, the sunlight in the region with higher latitude contains more blue light. Based on the same principle, most of the photos under the sea surface are blue, because seawater also absorbs non-blue light, but the rate at which seawater absorbs non-blue light is much higher than the atmosphere. Most of the non-blue light is up to one meter deep. Before, it was absorbed by the sea.
There are many methods for measuring the intensity and quality of light. Generally, the unit of measurement intensity is candlelight, lumen number, LUX, etc. This part is discussed in many articles, and will not be described here. The color of the light can be expressed by the color temperature (degrees Kelvin; oK), which is also the part of the average person who has doubts. The color rendering of light can be represented by the color rendering index (CRI).