Multiple choice general knowledge science & technology Infrared light has a wavelength that is too long or short to be visible for humans? Low High Short Long Reveal answer Fill a bubble to check yourself D Correct answer Explanation Infrared light has wavelengths longer than visible red light (approximately 700nm to 1mm). The term 'infra' means below, referring to its position below red light in the electromagnetic spectrum. It is invisible to the human eye.