As Ryan says, ultraviolet radiation is more energetic than infrared. But “hotter” is a somewhat informal term. A photon of UV radiation has a lot more energy than a photon of IR, but the total energy has to take into account the number of photons as well. read more
So infrared feels hot because we sense it as heat, and because when we feel its heat, there is a lot of radiation, which makes up for its lower energy content. We don't feel ultraviolet radiation, which is usually less abundant, at least until we get a sunburn. read more
No. Infrared (IR) light is longer wavelength (lower frequency) light and is of lower electromagnetic energy than shorter wavelength (higher frequency) ultraviolet (UV) light. Note that our skin"senses" infrared light (which we normally think of as heat) in a different way than it does ultraviolet light. read more
UV Light. UV light is measured in microwatts of ultraviolet radiation per lumen of visible light (µW/l). The high energy of UV radiation is particularly damaging to artifacts. UV light is not visible to the human eye and therefore removing it from museum lighting causes no change in appearance. read more