Answer:
The magnitude of the magnetic field is 8.333 x 10⁻⁷ T
Step-by-step explanation:
Given;
charge on the lightening bolt, C = 15.0 C
time the charge passes by, t = 1.5 x 10⁻³ s
Current, I is calculated as;
I = q / t
I = 15 / 1.5 x 10⁻³
I = 10,000 A
Magnetic field at a distance from the bolt is calculated as;

where;
μ₀ is permeability of free space = 4π x 10⁻⁷
I is the current in the bolt
r is the distance of the magnetic field from the bolt

Therefore, the magnitude of the magnetic field is 8.333 x 10⁻⁷ T