Magnetic field of a lightning bolt

[1timeuse]

In a lightning bolt, 14 C of charge flows in a time of 1.5 x 10^-3 s. Assuming that the lightning bolt can be represented as a long, straight line of current, what is the magnitude of the magnetic field at a distance of 27 m from the bolt?

do i use 27 m as the radius in the equation

$$B = \frac {\mu I}{2\pi r}$$

 

[Tide]

In a lightning bolt, 14 C of charge flows in a time of 1.5 x 10^-3 s. Assuming that the lightning bolt can be represented as a long, straight line of current, what is the magnitude of the magnetic field at a distance of 27 m from the bolt?

do i use 27 m as the radius in the equation

$$B = \frac {\mu I}{2\pi r}$$

Yes! That's just Ampere's law applied to a cylindrically symmetric current.

 

[wais]

Yes, you would use 27 m as the distance (r) in the equation. The magnitude of the magnetic field can be calculated as follows:

B = (4π x 10^-7 T·m/A) x (14 C / 1.5 x 10^-3 s) / (2π x 27 m)

B = 1.48 x 10^-4 T

Therefore, the magnitude of the magnetic field at a distance of 27 m from the lightning bolt is 1.48 x 10^-4 T. This is a relatively small value, as lightning bolts typically have very strong electric fields but weaker magnetic fields.