We can model a lightning bolt as a very long, straight wire. If a lightning bolt carries a current of 30 kA, and you are unfortunate enough to be 8.9 m away from the lightning bolt, how large of a magnetic field do you experience

Magnetic field experienced = 4.5 * 10⁻⁴ T

Explanation:

The magnetic field around an infinite straight current-carrying wire at a distance r from the wire is given by

B = (μ₀I) / (2πr)

B = ?

I = 20 KA = 20000 A

r = 8.9 m

μ₀ = magnetic permeability = 1.257 * 10⁻⁶ T. m/A

B = (1.257 * 10⁻⁶ * 20000) / (2π*8.9) = 4.5 * 10⁻⁴ T