Question

What does spectroscopy measure?

Answer 1

The interaction of light with matter.........

Explanation:

And thus for physical scientists, spectroscopy becomes the interaction of atoms and molecules with the electromagnetic spectrum. Some form of spectroscopy can usually be found to interrogate a particular atom or atomic particle or molecule. And this spectroscopy depends on (i) the nature of the light (radiation) absorbing species, and (ii) the number of absorbing species.

And thus spectroscopy can usually be made quantitative. Some idea of the concentration of a sample may be made given the strength, the intensity, of its absorption of radiation.