Silica sol Ludox (trademark) was studied by turbidimetry with the following results:
s,g/l 4.97 9.94 19.15 39.15
τ, m-1 2.42 4.52 7.86 12.94
at a light wavelength of 435.8 nm, a refractive index in the solvent of 1.3408, and a refractive index increment of 0.0625 cm3/g. Calculate the radius of the sol particles from these data, assuming a silica density of 2.278 g/cm3.

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