Answer:
The magnetic force is 0.3 N.
Explanation:
Given that,
Current in an unusual lightning strike, I = -400 A
The Earth’s magnetic field at that location is parallel to the ground and has a magnitude of 30 μT, 
We need to find the force exerted by the Earth’s magnetic field on the 25 m-long current.
The magnetic force is given by :

So, the magnetic force is 0.3 N.
I think its A as in density
They create energy ……………….
ಠ_ಠ Hey, hang on.. you might've made a discovery. Nobody has tested it so how do we know? ಠ_ಠ
Answer:
Jesus is in everyone's heart...
Just try to find him..:D