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(a) Sketch the electric field lines near a point charge $+q$. (b) Do the same for a point charge $-3.00q$.
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Final Answer

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Solution Video

OpenStax College Physics Solution, Chapter 18, Problem 33 (Problems & Exercises) (1:06)

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Video Transcript

This is College Physics Answers with Shaun Dychko. A positive charge <i>q</i> will have electric field lines radiating outwards from it because these electric field lines point in the direction that there would be a force on a positive test charts placed here. So for positive test charge that placed here, we repelled from this charge plus <i>q</i> and so electric field line is pointing in that direction, away from the charge. Then in part b, we have negative three <i>q</i>, so a positive test charge placed here would experience a force towards this charge of negative three <i>q</i>. And so the electric field lines have to point towards it. And electric field lines are going to be more dense because this charge has a magnitude three times greater than the charge in part a. And so, I've drawn three times of many field lines. So, in part a there are one, two, three, four, five, six lines radiating outwards. And in part b, if you count them all up there are 18 lines here pointing inwards.