2 x I0⁸ atoms of carbon are arranged side by side. Calculate the radius of carbon atom, if the length of this arrangement is 2.4 cm.

Let the radius of carbon atom = be r
$\text{ Then, }\text{ diameter }=2\mathrm{r}$
$$\begin{gathered} \text{ Number of atoms }=2\times {10}^8 \\ \text{ Total length formed }=2.4\mathrm{cm} \\ \therefore 2\mathrm{r}\times 2\times {10}^8=2.4 \\ \therefore \mathrm{r}=\frac{2.4}{4\times {10}^8}=6\times {10}^{-9}\mathrm{Cm} \\ =6\times {10}^{-11}\mathrm{m} \\ =60\times {10}^{-12}\mathrm{m}=60\mathrm{pm} \end{gathered}$$