In what form does infrared radiation primarily exist?

Infrared radiation primarily exists in the form of thermal energy. This is because infrared radiation is a type of electromagnetic radiation that has wavelengths longer than those of visible light but shorter than those of microwaves. It is primarily associated with heat, as objects emit infrared radiation when they are warmed above absolute zero. The energy transfer occurs through thermal radiation, which is the mechanism by which heat is transmitted. For instance, when you feel warmth from a heater or the sun, you are feeling the thermal energy produced by infrared radiation.

While light waves are part of the electromagnetic spectrum and include infrared radiation, they are a broader category that encompasses visible light and ultraviolet radiation as well. Thus, identifying infrared radiation specifically with thermal energy provides a clearer understanding of its primary physical characteristic and relevance in practical applications, such as temperature measurement and infrared sensing. Sound waves and electrical signals are distinct phenomena that do not relate directly to the nature of infrared radiation as thermal energy does.