Answer: 8.16*10^-4 T
Step-by-step explanation:
Given
Current of the lightening bolt, I = 20 kA
Distance from the strike of the lightening bolt, r = 4.9 m
To solve, we use the formula
B = [μ(0) * I] / 2πr, where
B = magnetic field of the lightening
μ = permeability constant = 4π*10^-7 N/A²
I = current of the lightening
r = distance from the lightening strike
B = [(4 * 3.142*10^-7) * 20*10^3] / (2 * 3.142 * 4.9)
B = (12.568*10^-7 * 20*10^3) / 6.284 * 4.9
B = 0.025 / 30.79
B = 8.16*10^-4 T
The magnetic field to be experienced would be 8.16*10^-4 T large