The wavelength range of visible light band

The wavelength range of visible light is between 780 and 400 nanometers.

I. Concept

Visible light is the part of the electromagnetic spectrum that can be perceived by human eyes, and the visible spectrum has no precise range; Ordinary people's eyes can perceive electromagnetic waves with a wavelength between 400 and 760 nm, but some people can perceive electromagnetic waves with a wavelength between 380 and 780 nm.

Visible to the naked eye is a short electromagnetic wave, which is called visible light from 0.4-0.76 micron. Visible light, after being split by a prism, becomes a light band composed of seven colors: red, orange, yellow, green, cyan, blue and purple. This band of light is called spectrum.

Among them, the wavelength of red light is the longest, the wavelength of purple light is the shortest, and the wavelengths of other colors are in between. There are infrared and radio waves whose wavelength is longer than red light (>: 0.76 micron); The wavelength is shorter than violet light (

Second, the visible spectrum

The visible spectrum has no precise range; Ordinary people's eyes can perceive electromagnetic waves with a frequency of 380 ~ 750 Hz and a wavelength of 780 ~ 400 nm, but some people can perceive electromagnetic waves with a frequency of about 340 ~ 790 Hz and a wavelength of about 880 ~ 380 nm.

People with normal vision are most sensitive to green light. The range of light visible to human eyes is influenced by the atmosphere. Except visible light and a few other bands, such as radio communication, the atmosphere is opaque to most electromagnetic radiation.

Application of visible light wavelength

1. Lighting:

The most basic application of visible light is lighting. White LED lamps, fluorescent lamps and incandescent lamps are all devices that use visible light to provide illumination.

2. Image capture:

Digital cameras, video cameras and eyes themselves create images by capturing visible light. This technology is applied to photography, film production, medical imaging and many other fields.

3. Optical communication:

Visible light is also used in optical communication, such as optical fiber communication. Optical signals are transmitted through optical fibers to realize high-speed data transmission, which is very important in the fields of Internet and communication.

4. Spectral analysis:

Visible spectrum analysis is used to determine the composition and properties of substances. This is very useful in chemistry, biology and environmental science.

5. Medical application:

Visible light is used in medical imaging, such as X-ray, MRI and CT scanning. In addition, medical equipment such as laser surgery and optical microscope also use visible light.

6. Plant growth:

Plants use visible light to synthesize nutrients through photosynthesis. Therefore, light management in agriculture and horticulture is very important for plant growth and development.