16 Jul '09 12:381 edit

Why is the boundary between the “near infrared” range and the “intermediate infrared” range defined as 1500nm (wavelength) and the boundary between the “intermediate infrared” range and the “far infrared" range defined as 20000nm (wavelength) ?

-what I mean is are these values just totally arbitrary values that someone just haphazardly and mindlessly conjured up in his head or is there some either practical or theoretical or scientific significance to these approximate boundary values and, if so, what is it? -just always wondered.

Does anyone here know?

-what I mean is are these values just totally arbitrary values that someone just haphazardly and mindlessly conjured up in his head or is there some either practical or theoretical or scientific significance to these approximate boundary values and, if so, what is it? -just always wondered.

Does anyone here know?