What category do infrared and radio waves fall under?

Infrared and radio waves are categorized as longwaves because they have longer wavelengths compared to other forms of electromagnetic radiation. In the electromagnetic spectrum, longwaves include wavelengths that can range from a few millimeters (in the case of radio waves) to several micrometers (for infrared waves). This characteristic is significant because it allows them to interact differently with matter compared to shorter wavelengths like visible light and X-rays.

For instance, infrared radiation is often associated with heat, as objects that emit heat energy release thermal radiation primarily in the infrared range. Radio waves can carry signals over long distances for communication purposes. Their lengthy wavelengths enable them to diffract around obstacles and effectively propagate through the atmosphere, making them ideal for broadcasting and radio transmissions.

In contrast, the other categories listed—shortwaves, visible light, and X-rays—are associated with shorter wavelengths and different properties and behaviors in terms of energy and interaction with materials. Visible light occupies a small range in the electromagnetic spectrum and is the range detectable by the human eye, while X-rays possess even shorter wavelengths and are used primarily in medical imaging due to their ability to penetrate softer tissues but not denser materials like bones.