Infrared(I think that's what you mean by infarade) waves encompass the region of the electromagnetic spectrum right before light, commonly considered as heat radiation. As it is present right before light, it has a frequency that is a bit lower, and a wavelength that is higher as a result of the equation given in a post above. Due to the lower frequency, it also has less energy, also given in an equation in a post above.
Or, in less nerdy terms, infrared is the segment before light, with lower energy/frequency.
Infrared is the part of the EM spectrum between the upper end of visible and microwaves.
Roughly 750 nm to about 1 mm. I am sure there is some disagreement on the upper boundary, but long wavelength IR and microwaves have a lot in common.
i want to know about wave length of infarade wave and working range
Typically, short-wave infrared (SWIR) is from 0.7 um to 1.1 um, the part of the spectrum we can't see but that Si detectors can still respond to. Mid-wave (MWIR) is about 3-5 um and long-wave (LWIR) is 8-12 um: both bands are set by absorbance bands of water, and the MWIR and LWIR bands are within 'transmission windows'. Going out further, for example in FTIR measurements, the far infrared can go out to about 20um or more.