It is one of the three primary colors of red, green and blue. Among these three primary colors, its wavelength is the shortest, ranging from 440 to 475 N nanometers, which belongs to short wavelength. Because sunlight is Rayleigh scattered by dust in the air, the clear sky is blue. Due to the absorption of light of about 750 nanometers by hydrogen-oxygen bonds in water molecules, a large amount of water is concentrated into blue.

2. Red

It can be mixed with blue (one of the three primary colors of light) to make red, or mixed with yellow to make orange. The complementary color of red is cyan. Red is one of the three primary colors of light. It can be mixed with green and blue to produce any color. Red is the color of the end of the long wave in the visible spectrum that excites the observer through energy, and the wavelength is about 6 10 to 750 nm.

3. The long wave of the visible part of orange electromagnetic wave is about 590~6 10nm. The middle tone between red and yellow. Also called orange or orange. Orange is a bright and lively color and the warmest color in the warm color system.

4. Green (surname); green

It is a darker color than tender grass, or bright green, and it is a color between green and yellow in the spectrum. Green is the middle wavelength part of the visible part of electromagnetic waves, with a wavelength of 492 ~ 577 nm.

5. Purple (purple)

Purple is a combination of warm red and cold blue, which is an excellent stimulating color. In China tradition, purple is a noble color. For example, the Forbidden City in Beijing is also called the Forbidden City, and there is also the so-called "purple gas coming from the east".

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