What exactly is radiation? Please talk about its chemical principles.

What is radiation?

All objects in nature, as long as the temperature is above absolute zero, are constantly transmitting heat outward in the form of electromagnetic waves. This method of transmitting energy The method is called radiation. The energy emitted by objects through radiation is called radiant energy, or radiation for short.

An important feature of radiation is that it is "reciprocal". Regardless of the temperature of the object (gas), it radiates outward. Object A can radiate to object B, and object B can also radiate to object A. This is different from conduction, which proceeds in one direction.

Heating occurs when radiant energy is absorbed by an object. Different radiant energy absorbed by the object will produce different temperatures. Therefore, radiation is an important way of converting energy into heat.

Radiation is emitted outward in the form of electromagnetic waves. It spreads energy in the form of waves. Radio waves and light waves are both electromagnetic waves. They propagate very quickly, at the same speed as light waves (3×1010 cm/sec) in a vacuum and slightly slower in air.

Electromagnetic waves are synthetic waves composed of waves of different wavelengths. Its wavelength ranges from cosmic rays of 10E-10 microns (1 micron = 10E-4 centimeters) to radio waves with wavelengths of several kilometers. Gamma rays, X-rays, ultraviolet rays, visible light, infrared rays, ultrashort wave and long wave radio waves all belong to the range of electromagnetic waves. What is visible to the naked eye is a very short section of electromagnetic waves, from 0.4 to 0.76 microns. This part is called visible light. After the visible light is split by a prism, it becomes a light band composed of seven colors: red, orange, yellow, green, cyan, blue, and violet. This light band is called a spectrum. Among them, red light has the longest wavelength, violet light has the shortest wavelength, and the wavelengths of other colors of light are in between. Those with wavelengths longer than red light (>0.76 microns) include infrared rays and radio waves; those with wavelengths shorter than purple light (<0.4 microns) include ultraviolet rays, gamma rays, X-rays, etc. Although these radiations are invisible to the naked eye, they can be measured with instruments.

The wavelength of solar radiation is mainly 0.15-4 microns, of which the maximum radiation wavelength is 0.5 microns on average; the wavelength of ground and atmospheric radiation is mainly 3-120 microns, of which the maximum radiation wavelength is 10 microns on average. It is customary to call the former shortwave radiation and the latter longwave radiation.

Radiation is a natural phenomenon and has nothing to do with chemistry!!