A human hair is about $5 \times 10^{-5}$ m thick. Side-by-side, how many hairs span 1 cm?

A human hair is about $5 \times 10^{-5}$ m thick. Side-by-side, how many hairs span 1 cm?
  1. $20$
  2. $200$
  3. $2000$
  4. $2$

Solution

$1$ cm $= 10^{-2}$ m. Number $= \dfrac{10^{-2}}{5 \times 10^{-5}} = \dfrac{1}{5} \times 10^{3} = 200$.

Asked in: NSO

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