Infrared frequency is relatively low (the order of frequency from low to high is: radio, microwave, infrared, visible light), giving people the feeling of heat, the effect is thermal effect, then the infrared penetrates in the process of penetration. At what level is the scope? If infrared rays can penetrate into the interior of atoms and molecules, it will cause the expansion of atoms and molecules, resulting in the disintegration of atoms and molecules. Is it really? In fact, the frequency of infrared rays is low and the energy is not enough, which is far from the effect of disintegrating atoms and molecules. Therefore, infrared rays can only penetrate the gaps of atoms and molecules, but cannot penetrate into the interior of atoms and molecules. Since infrared rays can only penetrate into the gaps of atoms and molecules, the vibration of atoms and molecules will be accelerated and the spacing will be enlarged. , that is, increasing the thermal motion energy. From a macroscopic point of view, the material is melting, boiling, and vaporizing, but the physical and chemical properties of the material (atoms and molecules themselves) have not changed. This is the thermal effect of infrared rays.
Therefore, we can use this excitation mechanism of infrared to grill food and denature organic polymers, but we cannot use infrared to generate photoelectric effect, and we cannot change the interior of atomic nuclei.
In the same way, we cannot use radio waves to grill food. The wavelength of radio waves is too long to penetrate the gaps of organic polymers, let alone denature them to achieve the purpose of cooking food.
From the above, we know that the shorter the wavelength, the higher the frequency and the larger the energy, the larger the penetration range; the longer the wavelength, the lower the frequency and the smaller the energy, the smaller the penetration range. For the range of diffraction energy, the opposite is true: the longer the wavelength, the stronger the diffraction ability; the shorter the wavelength, the weaker the diffraction ability.