Question

A strand of hair is approximately 50 μm thick. If the diameter of an atom is 1 × 10-10 m, how many atoms thick is a strand of hair?

Answer 1

Thickness of strand hair = 50 μm

Diameter of an atom  = $1 \times 10^{-10} m$

Now, with the help of conversion factors, convert thickness in micrometer into meter i.e. 1 micrometer = $10^{-6}m$

So, thickness of strand hair =50 μm= 50 \times 10^{-6} m

Therefore,

number of atoms thick is a strand of hair =  $50 \times 10^{-6}m\times \frac{1 atom}{1 \times 10^{-10}m}$

= $50\times 10^{4}atoms$

Hence, number of atoms is $50\times 10^{4}atoms$thick is a strand of hair.

Answer 2

Answer : The number of atoms thick in a strand of hair are $5\times 10^5\text{ atoms}$

Explanation : Given,

Diameter of an atom = $1\times 10^{-10}m$

Thickness of strand of hair = $50\mu m=50\times 10^10^{-6}m$

conversion used : $1\mu m=10^{-6}m$

Now we have to determine the number of atoms thick in a strand of hair.

$\text{Number of atoms thick}=\frac{50\times 10^10^{-6}m}{1\times 10^{-10}m}=5\times 10^5\text{ atoms}$

Therefore, the number of atoms thick in a strand of hair are $5\times 10^5\text{ atoms}$