I am never sure if I am on the right track when answering my homework problems. Anyway the problem involves a long solid cylinder of radius R and uniform charge distribution throughout its volume. We are supposed to choose a cylindrical gaussian surface of radius r and length L with r < R - so the gaussian surface is inside the cylinder. We are 1st supposed to determine q(enclosed) in terms of ρ (rho), L and r - and of course any other relevant constants. So first off - I am looking at the flux within the cylinder --- already I am nervous about this because I cannot think of how to imagine the flux within this cylinder... and then considering E ??? So to further explain where I am at - since the cylinder is "very very long" I have capped off the gaussian cylinder inside the whole. 1st off - is q(enclosed) a ratio of the whole Q ? or is it constant within the cylinder (I don't think q = Q). I want to consider q/Q - where q = π(pi) r² L then Q = π R² L - then I want to take q/Q = (π(pi) r² L )/(π R² L ) - cancel the π(pi) and L to get q =(Qr²)/R² - then I wonder if I am getting anywhere = also does q = ρL - it shows in my book that q = λL (λ is linear charge density) and I don't know if it works for volume charge density too... :uhh: - feeling like a physics flunky....(adsbygoogle = window.adsbygoogle || []).push({});

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# Homework Help: Volume Charge Density in a long Cylinder

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