Answer
0.1 N. Your answer may vary depending on the estimates you make.
Work Step by Step
In Example 18–10, the current in a lightning bolt is estimated to be 100 A. Use equation 20–2 to find the force on the pole, assuming the Earth’s magnetic field is horizontal. Assume the flag pole is 20 m tall.
$$F=I\mathcal{l}B $$
$$F= (100A)(20m)(5.0\times10^{-5}T) =0.1N $$