Write the formula for the magnetic field at a perpendicular distance $r$ from a finite current-carrying wire.

(N/A) For a finite wire carrying current $I$,the magnetic field $B$ at a perpendicular distance $r$ from the wire is given by the Biot-Savart law.
If the wire subtends angles $\theta_1$ and $\theta_2$ at the point of observation with respect to the perpendicular line drawn from the point to the wire,the formula is:
$B = \frac{\mu_0 I}{4\pi r} (\sin \theta_1 + \sin \theta_2)$
where:
- $\mu_0$ is the permeability of free space.
- $I$ is the current flowing through the wire.
- $r$ is the perpendicular distance from the wire to the point.
- $\theta_1$ and $\theta_2$ are the angles subtended by the ends of the wire at the point.