Chapter 28, Problem 38P

To determine

Show that the magnetic field $\overrightarrow{\text{B}}$ produces at a point $\text{P}$ is given by, $\overrightarrow{\text{B}}\text{=}\frac{{\mu }_0}{4\pi }\frac{q\overrightarrow{\text{v}}\times \overrightarrow{\text{r}}}{r^3}$.