In UV spectroscopy, when a beam of light is shone into solution, what is scattering loss during this process?
Scattering is the redirection of the 'beam' of light, as is illustrated in the diagram below:
Source: University of Wisconsin
The description from the document Fundamentals of modern UV-visible spectroscopy (Figure 46) states that
Scattering causes an apparent absorbance because less light reaches the detector
They also detail two main types of scattering in UV spectroscopy (Figure 47):