{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

I say ppttuy yukk never ask which equation ask what

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: is a property of the object!! (concentric cylinders here) • Assume some Q (i.e., +Q on one conductor and –Q on the other) • These charges create E field in region between conductors • This E field determines a potential difference V between the conductors • V should be proportional to Q; the ratio Q/V is the capacitance. 33 cross-section a4 a3 Calculation Calculation A capacitor is constructed from two conducting cylindrical shells of radii a1, a2, a3, and a4 and length L (L >> ai). a2 a1 metal metal What is the capacitance C of this capacitor ? C≡ Q V • Strategic Analysis: – – – – Put +Q on outer shell and –Q on inner shell Cylindrical symmetry: Use Gauss’ Law to calculate E everywhere Integrate E to get V Take ratio Q/V: should get expression only using geometric parameters (ai, L) Note: Many of you email me and ask “prof—what equation should I use for homework problem 3?” I say: Ppttuy, yukk! Never ask which equation! Ask what concepts should I apply and equations say: will become obvious. will Calculation Calculation cross-section +Q A capacitor is constructed from two conducting cylindrical BB shells of radii a1, a2, a3, and a4 and length L (L >> ai). + + + + + + + ­Q + + + + + metal + + + What is the capacitance C of this capacitor ? + a2 a1 + a4 a3 + C≡ + Q V metal Where is +Q on outer conductor located? (A) at r=a4 (B) at r=a3 (C) both surfaces (D) throughout shell Why? Gauss’ law: Q dA ∫ Eg = ε enclosed Q 0 enclosed =0 We know that E = 0 in conductor (between a3 and a...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern