Which sampling process sorts a sample to obtain uniform particle sizes using screens of predetermined size?

Which sampling process sorts a sample to obtain uniform particle sizes using screens of predetermined size?

• A. Centrifuge
• B. Sieve
• C. Filters
• D. Sedimentation

Answer: (B)

Sorting a mixture by particle size using screens with fixed openings is called sieving (screening). The idea is to pass the material through a stack of screens, each with a known mesh size. Particles larger than a screen’s opening are retained, while smaller ones pass through to the next screen. By using several screens in sequence, you can separate the sample into fractions with relatively uniform particle sizes corresponding to each mesh size. This method is precisely what “predetermined screen size” implies and is the standard way to obtain uniform particle sizes in solid materials. Why this is the best fit: sieving directly enforces size-based separation with fixed openings, producing distinct size fractions. The other methods work on different principles: a centrifuge uses centrifugal force to separate by density and mass, not by size through a screen; filtration relies on pore passage to remove particles from liquids and isn’t typically used to create uniform size fractions of dry solids; sedimentation depends on settling velocity under gravity (or an accelerated field), which is influenced by size and density but does not rely on screens to define sizes.

Sorting a mixture by particle size using screens with fixed openings is called sieving (screening). The idea is to pass the material through a stack of screens, each with a known mesh size. Particles larger than a screen’s opening are retained, while smaller ones pass through to the next screen. By using several screens in sequence, you can separate the sample into fractions with relatively uniform particle sizes corresponding to each mesh size. This method is precisely what “predetermined screen size” implies and is the standard way to obtain uniform particle sizes in solid materials.

Why this is the best fit: sieving directly enforces size-based separation with fixed openings, producing distinct size fractions. The other methods work on different principles: a centrifuge uses centrifugal force to separate by density and mass, not by size through a screen; filtration relies on pore passage to remove particles from liquids and isn’t typically used to create uniform size fractions of dry solids; sedimentation depends on settling velocity under gravity (or an accelerated field), which is influenced by size and density but does not rely on screens to define sizes.