Question

If the diameter of a carbon atom is `0.15 nm`, calculate the number of carbon atom which can be placed side by side in a straight line length of scale of length `20 cm` long.

Answer 1

1 m = 100 cm
1 cm = `10^(-2) m `
Length of the scale = 20 cm
= `20 xx 10^(-2)` m
Diameter of a carbon atom = 0.15 nm
= ` 0.15 xx 10^(-9) `m
One carbon atom occupies `0.15 xx 10^(-9) m `
`therefore` Number of carbon atoms that can be placed in a straight line
= `(20 xx 10^(-2)m )/(0.15 xx 10^(-9) m )`
= `133.33 xx 10^(7)`
= `1.33 xx 10^(9)`