These waves have frequency range from 3 x 1011 Hz to 4 x 1014 Hz.
They are produced or emitted by all hot objects and molecules. These waves are easily absorbed by objects in the surroundings, there by cansing heating effect in them. Because of this, infrared (IR) radiations are some times referred to as ‘heat waves’.
Infrared waves (or radiations) are used for a variaty of applications like:
• Physical therapy for treating muscular strain (infrared lamps are used for this).
• Solar water heater, solar cooker, solar cells, remote sensing satellites.
• Drying purposes (fruits and vegetables).
• Night vision goggles
• Imprared LEDs, used in remote controles to operate electronic systems in TV sets, video recorders, hi-fi system, ACs, set-top boxes etc.
• Green houses to keep plants warm.
(Infrared waves trapped by green house gases like CO2 and water vapour, helps keep the earth warm. But excessive green house gases can cause global warming).
