Infrared Rays

**Definition:** That portion of the electromagnetic spectrum usually sensed as heat. Infrared wavelengths are longer than those of visible light, extending into the microwave frequencies. They are used therapeutically as heat, and also to warm food in restaurants.

**Tree numbers:** - G01.358.500.505.650.552 - G01.590.540.552 - G01.750.250.650.552 - G01.750.770.578.552 - G16.500.275.063.725.525.400 - G16.500.750.775.525.400 - N06.230.300.100.725.525.400

**Synonyms:** - Heat Waves