I want know near infrared(interaction+scattering)?

Answer 1

Near infrared is composed of wavelength just higher than the visible wavelength from 800 nm to 10µm.

This domain is especially interesting since the molecular vibrations have energy corresponding to that of these wavelength and thanks to the rays we can study the vibrations of bound in the inner of molecules.
Water is a Strong absorber of these wavelengths so with infrared device you can see persons in the darkness. The rays are absorbed and a device interprets this absorption