Ordinary ''lead'' pencils actually are made of a form of carbon called graphite. If a pencil line is `0.35 mm` wide and the diameter of a carbon atom is `1.5 xx 10^(-10)m`, how many `C` atom wide is the line?

Options

A. `2.3xx10^(6)`atoms
B. `7.8xx10^(6)`atoms
C. `5.6xx10^(6)`atoms
D. `9.7xx10^(6)`atoms

Answer

A

Explanation

Number of `C` atoms
`=("Width of the pencil line in meters")/("Diameter of a single "`C`" atom in meters")`
`= 0.35mm xx (1m)/(1000mm)xx (1C "atom")/(1.5xx10^(-10)m)`
`= 2.3 xx 10^(6)C` atoms