Final answer:
Using the sizes given, one smoke particle would be 3.3 μm, so 330 μm / 3.3 μm equals 100, but this contradicts the PM2.5 size. Corrected calculations for PM2.5s (330 μm / 2.5 μm) would yield 132 smoke microparticles, which is not an option. The most accurate given option considering the typo is D) 330.
Step-by-step explanation:
The question is based on a comparison between the size of a grain of salt and smoke microparticles that are harmful to human health. The smoke particles in question are PM2.5s, which are less than 2.5 micrometers in size. Given that a smoke particle is 100 times smaller than a grain of salt, and that a grain of salt is 0.33 mm long, we can calculate the number of smoke microparticles required to match the length of the salt grain.
To find the length of one smoke particle, we convert 0.33 mm to micrometers (1 mm = 1000 μm), resulting in 330 μm for the grain of salt. Since one smoke particle is 100 times smaller, its length would be 330 μm / 100 = 3.3 μm. To line up to the length of the grain of salt, it would take 330 μm / 3.3 μm = 100 smoke microparticles. However, we need to correct the original statement as it's evident that it contains a typographical error — if a smoke particle is indeed 100 times smaller than a grain of salt, it would be 3.3 μm, not less than 2.5 μm as PM2.5 particles are described. Therefore, by the correct measurements, the answer would be 330 μm / 2.5 μm (size of PM2.5) = 132 smoke microparticles, this is not an option given by the question. The closest answer to the corrected calculation is 330 μm / 2.5 μm = 132, which can be rounded down to option D) 330 considering the next closest option is a magnitude larger.