[AG]

We know that most of the remote controls use IR radiation which one cant see with naked eyes. But on looking through a mobile camera, a light is visible on the head (transmitting end) of remote control when working. 
What would be the reason?

[Borek]

Camera sensor is not an eye, so its spectral sensitivity is different.

Besides, some people DO see remotes emissions. I recall someone telling a story about his GF using remote to find keys in the dark.

[AG]

that i know, camera sensor is not an eye.
But how the IR frequency is converted in to visible region on looking through the camera..?

[Borek]

How does the sensor work?

[AG]

I dont know Borek. can you help me please. i would like to hear, if you share..

[Borek]

Stop whining, start searching and reading.

http://en.wikipedia.org/wiki/Image_sensor

[AG]

Hmm.. Thanks for your valuable information

[fledarmus]

This might be more helpful:

http://en.wikipedia.org/wiki/Infrared_sources

The infrared region that is used for remote control devices is the near-infrared range (700-1000nm wavelength), lying just beyond the range that the human eye can detect (~385 to ~700nm with some individual variation). But the LEDs used to produce the IR light are not lasers, and rather than producing a single wavelength of radiation, they produce a distribution of radiations, some of which are slightly outside the near IR range and are detectable by the eye. The part that you can't see is presumably much brighter than the part you can - what you perceive as a dim red light is probably a very bright IR light with just a little spillover into the visible spectrum.