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Session 2 c palmer august 8 2013

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Unformatted text preview: ∫ QEnclosed E ⋅ dA = ε0 Altogether σA 2 E (d ) * A = ε0 σ E (d ) = 2ε 0 Surprising result! The electric field is constant throughout space! Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 40   The conducting slab is very similar to the infinite charged plane.   There is still charge density σ [C/m2] > 0 on the surface.   However, now the conductor has some thickness and the electric is not the same on both sides of the charged surface. Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 41   What is the main difference in the setup of charged conducting slab w.r.t. the charged plane? A)  The electric field is not uniform at distance, r, from the plane. B)  The electric field is 0 inside the conductor. C)  We need a different shape for the Gaussian surface. D)  We have no symmetry. Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 42   What is the main difference in the setup of charged conducting slab w.r.t. the charged plane? A)  The electric field is not uniform at distance, r, from the plane. B)  The electric field is 0 inside the conductor. C)  We need a different shape for the Gaussian surface. D)  We have no symmetry. Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 43   The charge on a conductor goes to the surface   Draw any Gaussian surface inside it Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 44   The charge on a conductor goes to the surface   Draw any Gaussian surface inside it   No charge inside   No flux   No electric field Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 45   There is still charge density σ [C/m2] > 0 on the surface.   Setup is the same except, the bottom of the Gaussian Surface goes through the conductor   Where the electric field is 0!! Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 46 Φ Elec = ∫ QEnclosed E ⋅ dA = ε0 Left hand side ∫ E ⋅ dA = ∫ E (d ) dA Right hand side Cylin der Top +∫ E (− d ) dA + ∫ E ⋅ dA Bottom Si de Enclosed = E (d )∫ dA + ∫ 0 * dA Q Top = E (d ) * A Bottom ε0 Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 σA = ε0 47 Φ Elec = QEnclosed E ⋅ dA = ε0 Altogether σA E (d ) * A = ε0 σ E (d ) = ε0 Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 48   We are nearly finished with chapter 23 now.   Monday we will review spherical symmetry and Gauss’s Law.   I envision the exam next week covering   Electric Force   Electric Fields   Gauss’s Law   NOT electric potential   Do the homework for ch 21-23 this weekend   If you want to get ahead read chapter 24.   Getting ahead is a good idea. Physics 2B - Summer Session 2 - C. Palmer August 8, 2013 49...
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This note was uploaded on 09/10/2013 for the course PHYS 2B 2b taught by Professor Hirsch during the Summer '10 term at UCSD.

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