electromagnetic radiation principle
The phenomenon of electromagnetic waves generated by the interactive changes of the electric and magnetic fields. The phenomenon that electromagnetic waves are emitted or leaked into the air is called electromagnetic radiation. Electromagnetic radiation is an invisible and intangible field. The earth on which humans live is a large magnetic field. Both thermal radiation and lightning on its surface can generate electromagnetic radiation. The sun and other planets also continuously generate electromagnetic radiation from outer space. Natural magnetic fields around the human body, sunlight, household appliances, etc. all emit radiation with different intensities. Electromagnetic radiation is an external manifestation of the movement of atoms and molecules inside a substance.