These days we are familiar with TV remotes and for that matter various remotes .
How do these remotes work ? What kind of radiations take place in them ? What makes the signals given by these to cross a glass sheet also ? What is the mechanism behind these ?
Infrared is still a kind of (not for us humans) light. Glass is not a barrier for this radiation (green house effect). Try a pice of paper and you will find out that infrared will not pass through this obstacle.
Remote controller use pulse modulation or frequency modulation of infrared light to carry information to the receiver..
Really a lot of thanks for those articles... very informative... one last thing... those rays travel through glass and not paper...so what is the basic property behind this? I couldn't get it... How is the information retained even after the ray hits a glass?
those rays travel through glass and not paper...so what is the basic property behind this? I couldn't get it... How is the information retained even after the ray hits a glass?
IR is just a type of light which is on the part of the spectrum that humans can't see. If you have a digital camera or anything with CCD, you can see the light there. Don't think of them as rays or radiation, it's just light. Light can travel through glass. like windows for example, because they are transparent. Paper doesn't work because it's only translucent not transparent.
As for keeping the data, as long as the light passes through the medium, it's modulation should still be intact.
Thermal imaging - This technology operates by capturing the upper portion of the infrared light spectrum, which is emitted as heat by objects instead of simply reflected as light. Hotter objects, such as warm bodies, emit more of this light than cooler objects like trees or buildings.
Anything above 0 K i.e -273 °C emits electromagnetic radiation. Most of this radiation is emitted within a small wavelength range. This range varies with the temperature of the body. For bodies around room temperature, this range falls within the IR range.