photography using film with an emulsion that is sensitive to infrared light, enabling it to be used in misty weather, in darkened interiors, or at night. It has applications in aerial surveys, the detection of forgeries, etc
- Infrared radiation
infrared radiation [(in-fruh-red)] Invisible radiation in the part of the electromagnetic spectrum characterized by wavelengths just longer than those of ordinary visible red light and shorter than those of microwaves or radio waves. (Compare ultraviolet radiation.) Note: The heat we feel from a glowing coal or an incandescent light bulb is from infrared rays.
noun, Astronomy. 1. a star radiating strongly in the infrared portion of the electromagnetic spectrum.
- Infrared telescope
infrared telescope A telescope, similar in operation to an optical telescope, that is designed to detect infrared radiation. Because infrared radiation is emitted by warm objects, infrared telescopes need to be shielded from local heat sources, as by chilling them with liquid nitrogen or locating them in polar regions. Many are placed on high mountains […]
[in-fruh-son-ik] /ˌɪn frəˈsɒn ɪk/ adjective 1. noting or pertaining to a sound wave with a frequency below the audio-frequency range. adj. 1927, from infra- + sonic. infrasonic in·fra·son·ic (ĭn’frə-sŏn’ĭk) adj. Generating or using waves or vibrations with frequencies below that of audible sound. infrasound (ĭn’frə-sound’) Sound whose wave frequency is too low (under 15-20 hertz) […]