Question

Currents during lightning strikes can be up to 50000 A (or more!). We can model such a strike as a 49500 A vertical current perpendicular to the earth's magnetic field, which is about 12 gauss.
a. What is the force on each meter of this current due to the earth's magnetic field?

Answer 1

Answer:

59.4 N

Explanation:

The force exerted on a current-carrying wire due to a magnetic field perpendicular to the wire is given by

$F=ILB$

where

I is the current in the wire

L is the length of the wire

B is the strength of the magnetic field

Here in this problem, we model the strike as a current-carrying wire, so we have:

I = 49,500 A is the current

L = 1 m is the length (we want to find the force per each meter of length)

$B=12 G = 12\cdot 10^{-4} T$ is the strength of the magnetic field

Therefore, the force on each meter of the current due to the magnetic field is:

$F=(49,500)(1)(12\cdot 10^{-4})=59.4 N$