sentence: Red light has the longest wavelength that human eyes can see.
sentences_before: The wave is longer than light which humans can see and shorter than microwaves. The word 'infrared' means 'below red'.
sentences_after: Infrared waves cannot be seen by the eye. People sense infrared as heat. Most remote controls use infrared to send the control signals.
concept_name: red light
headings: Infrared
categories: Physics Chemistry