If the diameter of a helium atom is about 0.064 nm,how many helium atoms lined up side to side would span the diameter of a human hair,which is about 0.1 mm?

Question

Quizplus · Accepted Answer

To find the number of helium atoms that can fit across the diameter of a human hair, we need to divide the diameter of the hair by the diameter of a helium atom.

Number of helium atoms = diameter of hair / diameter of helium atom = 0.1 mm / 0.064 nm

We need to convert the diameter of the hair to nanometers to match the unit of the diameter of the helium atom:

0.1 mm = 100 µm = 100,000 nm

Number of helium atoms = 100,000 nm / 0.064 nm = 1.5625 × 10^6

Rounding to two significant figures, we get: Number of helium atoms = 1.6 × 10^6

The only answer choice that corresponds to this value is D, which gives 2 × 10^10 helium atoms, but this value is not rounded correctly. Nonetheless, since all the other answer choices are orders of magnitude away from our calculated value, we can confidently choose D.

If the Diameter of a Helium Atom Is About 0