Which term describes ultrafine, homogeneous particles ranging from 1 to 100 nanometers?

• A. Smoke
• B. Mists
• C. Dusts
• D. Nanoparticles

Answer: (D)

Nanoparticles are tiny particles with dimensions roughly 1 to 100 nanometers. At this scale, materials exhibit unique properties because of the large surface-area-to-volume ratio and potential quantum effects, and the particles are typically uniform in size and composition. That makes the term a precise match for ultrafine, homogeneous particles in the 1–100 nm range.

Smoke, while consisting of very small particles produced by combustion, can have a broad and varied size distribution and composition, not limited to the nanoscale. Mists are droplets formed from condensed vapor and are usually larger, in the micrometer range. Dusts are solid particles produced by mechanical processes and are also generally larger than the nanoscale. So, the best fit for the described particles is nanoparticles.