Ch24-28sheet - Ch. 24 For a capacitor with Q and -Q: C = C...

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Ch. 24 For a capacitor with Q and -Q: C = Q Δ V C k plates = ± 0 A d In parallel, V = V n , so C eq = Σ C n . In series, Q = Q n , so C eq = 1 Σ 1 Cn . Δ U = 1 2 CV 2 = 1 2 QV = 1 2 Q 2 C Energy density u = 1 2 ± 0 E 2 Ch. 25 I = dQ dt J := I A = nqv d , where J is current density, A is the cross-sectional area of the conductor, n is the particle density, and v d is drift velocity. ρ := E J , where ρ is resistivity, which represents the material dependence of resistance ρ ( T ) = ρ 0 (1 + α ( T - T 0 )) Corrolaries: R = ρL A , where V = EL V = IR terminal voltage: V = emf - IR int emf - IR int - IR ext = 0 P = IV = I 2 R = V 2 R = emf * I - I 2 R int 0.1 Ch. 26 In series: I eq = I n for all n, so R eq = R n In parallel: V eq = V n for all n, so 1 R eq = 1 R n Kirchhoff’s laws: 1. I = 0, where I is the current into a junction. (conservation of charge) 2. V = 0, where V is the voltage around a closed loop. (electrostatic force is conservative) Do loop rule on n loops, where n is the number of internal loops, and the loops include all the circuit elements. Ammeter is in series, ideally R = 0. Voltmeter is in parallel, ideally
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This note was uploaded on 04/01/2008 for the course PHYSICS 260 taught by Professor Evrard during the Fall '07 term at University of Michigan.

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