quiz6

# electrostatic energy u k q1q2 capacitors q cv

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Unformatted text preview: N/C " kdq r ; V= kpcos # (dipole) ; r2 El = \$ ! ! ! Electrostatic energy : U = k q1q2 ; Capacitors : Q = CV ; with dielectric : C = "C 0 ; #0 = 8.85 pF /m r %V %l ; r r E = -&V ! ! ! ! ! ! ! ! ! ! 2#"0 L ab cylindrical ; C = 4 #"0 spherical ln(b /a) b\$a Q2 1 1 1 Energy stored in capacitor : U = = QV = CV 2 ; U = " dv uE ; uE = #0 E 2 2C 2 2 2 Capacitors in parallel : C = C1 + C2 ; in series : C = C1C2 /(C1 + C2 ) Elementary charge: e = 1.6 "10 -19 C r r r r r r r r dq eE\$ m l I= = # J " dA ; J = nev d ; v d = ; % = 2 ; R = % ; E = % J , J = &E dt m ne \$ A #1 #1 V = IR ; ! = VI = I 2 R = V 2 /R ; Pemf = "I ; Req = R1 + R2 (series) ; Req = R1#1 + R2 (parallel) P Charging capacitor : Q(t) = C"(1# e#t / RC ) ; Discharging capacitor : Q(t) = Q0e#t / RC r r r r r r r Force on moving charge : F = q( E + v " B) ; force on wire : dF = Id l " B v2 mv 2" m Circular motion : a = ; radius r = ; period T = r qB qB r r r r r r r Magnetic dipole : = IA ; torque : " = # B ; energy : U = \$ % B r r 0 Id l # r r r ^ N Biot - Savart law : dB = ; 0 = 4 " #10\$7 2 ; Ampere's law : & B % d l = 0 Ienc 2 4" r A r r 0 I 0 Ia 2 0 Long wire : B = ; loop, along axis : B = ; dipole : B = 2" r 2(a 2 + z 2 ) 3 / 2 2" x 3 r r NI s...
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## This note was uploaded on 03/03/2010 for the course PHYS 2b taught by Professor Schuller during the Winter '08 term at UCSD.

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