## Essential University Physics: Volume 1 (3rd Edition)

We know that The number of atoms in a cell can be determined as follows $n=\frac{\frac{4}{3}\pi(\frac{D_{cell}}{2})^3}{\frac{4}{3}\pi(\frac{D_{atom}}{2})^3}$ $n=(\frac{D_{cell}}{D_{atom}})^3$ We plug in the known values to obtain: $n=\frac{10\times 10^{-6}}{0.1\times 10^{-9}}^3=(10^5)^3=10^{15}$ Thus, we can conclude that the number of atoms in a cell and the number of cells in the body are almost same.