Step 1:
The magnetic field due to a magnetic dipole along its axis is given by:
$$B = \frac{\mu_0}{4\pi} \frac{2\mu}{r^3}$$
where $\mu_0 = 4\pi \times 10^{-7} T m/A$, $\mu$ is the magnetic dipole moment, and $r$ is the distance from the center of the dipole.
Show more…