This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Nephelometry is based on the principle of - 
Select and explain. 
A. Light attenuated in intensity by scattering, B. Refraction of light, C. Reduced transmission of light, D. Filtration of solutes by kidney
A: Light attenuated in intensity by scattering
Answer: A: Light attenuated in intensity by scattering 
Explanation: Both nephelometry and turbidimetry methods are based on the phenomenon whereby light, passing through a medium with dispersed particles of a different refractive index from that of the medium, is attenuated in intensity by scattering.
In turbidimetry, the intensity of light transmitted through the medium, the unscattered light, is measured.
In nephelometry, the intensity of the scattered light is measured, usually, but not necessarily, at right angles to the incident light beam.