How does infrared ray works?

Answer 1

Infrared is just a colour of light, but one that our eyes cannot see. You can think of the different colours of light as having different wavelengths. Our eyes can see light with wavelengths between blue (short wavelength) and red (long wavelength). Infrared has an even longer wavelength than red light, but our eyes can't see it. If you hold your hand up to a fire, it feels warm. This is beause very long wavelength infrared warms you up. An infrared ray is invisible to your eye, but technologists can build sensors that can detect it. When you use your TV remote control to change a channel on a TV, selecting the channel on the remote tells the device to send out infrared light of a particular frequency. The light from the remote control (invisible to us) is picked up by a sensor on a TV, and depending on the frequency of the infrared, the TV decides what channel to select.