Infrared radiation

Electromagnetic or infrared radiation occupies a spectral region between the electromagnetic wave that a human eye notices, its red end and microwave or microwave radiation. A large difference in the optical properties of substances is noticed between perception in infrared and visible radiation. For example, for short-wave infrared radiation, water of a few centimeters thick is opaque.

About 50% of the sun's radiation falls on this species. It is an integral part of gas discharge and incandescent lamps, and some lasers are capable of emitting infrared radiation. To register it, photovoltaic and thermal receivers or special photographic materials are used.

The range of infrared radiation has three components: short-wave, medium-wave and long-wave regions. The long-wavelength region is subdivided into sublimated or terahertz radiation.

Human skin perceives infrared radiation from heated objects as a thermal sensation, therefore it is also called "thermal". The wavelength emitted by the heat depends on the heating temperature. If the temperature is high, then the wavelength will be short, and the intensity of its radiation is higher. Excited ions and atoms emit infrared radiation. In this range at relatively low temperatures lies the electromagnetic spectrum of radiation of an absolutely black body.

The astronomer W. Herschel discovered electromagnetic radiation in 1800, after which infrared radiation was studied in detail. Herschel determined its properties by means of thermometers. As a result of the experiments it was proved that the temperature varies in different parts of the visible spectrum. Herschel defined the following: the maximum heat that lies outside the saturated red color is also possible for its visible refraction.

Modern laboratory sources of infrared radiation are based on molecular solid-state gas lasers. In them, the frequency of radiation is regulated and fixed.

To register thermal radiation, special photographic plates are used. The photoresistor and the photoelectric detector have a much wider range of sensitivity.

Infrared radiation has unusual abilities. Its properties are such that it can be applied in various areas:

• Medicine - in physiotherapy;
• Sterilization of food for disinfection;
• Remote control - in TV consoles, automatic and security systems, some models of mobile phones;
• Painting - the energy expended and the speed is much less than with the convection method;
• As an anticorrosive agent;
• Food industry - electromagnetic waves of a certain range have a thermal and biological effect on the product, which helps to accelerate biochemical transformations in biopolymers;
• Agricultural industry;
• Heating of premises of streets and houses, for main and additional heating;
• Verification of money for authenticity, etc.

Infrared radiation can cause harm to the eyes of a person. In places where high heat occurs, infrared radiation can be dangerous to the eyes and when it is not yet accompanied by a visible light source. In these cases, you must use protective eyewear.

In other cases, infrared radiation can not harm a person. It is absolutely safe and does not have anything like ultraviolet or X-ray radiation.

Infrared radiation used in cooking makes the food very tasty, as all minerals and vitamins are preserved, while with a microwave oven it has nothing in common.

In general, we can say that there are practically no areas where infrared radiation is not used today.