Question

Which of the following ranges of particle size defines nano scale ?

• A. \(10\text{-}100\) nm
• B. \(1000\text{-}2000\) nm
• C. \(1\text{-}100\) nm
• D. \(100\text{-}1000\) nm

Hint:

Nanoscale is 1 to 100 nanometres.

Answer 1

The Correct Option is C

Step 1: Scale
1 nm = $10^{-9}$ m and 100 nm = $10^{-7}$ m.

Step 2: Definition
Particles are called nanoparticles when their size is within $10^{-9}$ to $10^{-7}$ m.

Step 3: Eliminate
Options with 1000 nm or more are $10^{-6}$ m, i.e. micrometre scale. The 10-100 nm option misses the smallest nanoparticles, such as 2-nm quantum dots.

Step 4: Answer
Option (C).

Final Answer:
The nanoscale is 1-100 nm. This is option (C). \[ \boxed{\text{(C) }1\text{-}100\ \text{nm}} \]