1) A bolt of lightning can carry a current of 250,000 A. How many times stronger is the magnetic field produced by a lightning bolt at a perpendicular distance of 10 m from the lighting, as a multiple of the Earth's magnetic field of ~57.5 ?T.
2) Calculate the magnetic force per meter between two such lightning bolts separated by 10 meters. (This is mainly to give a feeling for the strength of the magnetic field).