## Fundamentals of Physics Extended (10th Edition)

$\sigma=12\times 10^{-9} \frac{C}{m^2}$
We know that the surface charge density can be calculated as: $\sigma=\frac{q}{A}$ For the sphere with area $A=4\pi r^2$: $\sigma=\frac{3.3\times 10^{-9}}{4(3.1416) (0.15)^2}$ $\sigma=1.17\times 10^{-8}$ $\sigma=11.7\times 10^{-1}\times 10^{-8}$ $\sigma=12\times 10^{-9}$ $\sigma=12n\frac{C}{m^2}$