Question
A large lightning bolt had a 20,000-A current and moved 30.0 C of charge. What was its duration?

$1.50 \textrm{ ms}$

Solution Video

# OpenStax College Physics Solution, Chapter 20, Problem 5 (Problems & Exercises) (0:38)

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Video Transcript

This is College Physics Answers with Shaun Dychko. Current is the charge that moves divided by the time it takes for it to move. For this lightning bolt we want to know what the duration of the lightning bolt is. So we have to solve this for <i>t</i>. So we multiply both sides by <i>t</i> and divide by <i>I</i>. Then on the left side the I's cancel leaving us with <i>t</i> on the left. On the right side the t's cancel leaving us with <i>Q</i> divided by <i>I</i>. So that's 30 coulombs divided by 20,000 amps which gives 0.00150 seconds which is 1.50 milliseconds.