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## PH 213 (Electricity and Magnetism)

### You Should Have Memorized These

EquationNameEqPage SectionPage
·=out, ×=in
Representation of DirectionN/AN/AN/AN/A
F=kQ1Q2/r²Coulomb’s Law21-155021-5549
ε0=1/(4πk)Permittivity of Free SpaceN/A55121-5549
E=F/qElectric Field21-355421-6554
E=kQ/r²Field From Point Charge21-4a55421-6554
E=σ/ε0Field Between Plates21-856221-8561
ΦE=E·A=EA cos θFlux for Uniform E22-157622-1576
ΦE=∫dAElectric Flux Thru Surface22-357722-1576
ΦE=Qencl0Gauss's Law22-457822-2578
V=U/q=-W/qElectric Potential23-159223-1591
V=-EdPotential for Uniform E23-459523-2595
V=-∫dlElectric Potential
23-3
595
23-2
595
V=kQ/r, V=0@r=∞Potential, Point Charge23-559723-3597
El=-dV/dl or E=-VE Determined From V23-8/9602/323-7602
U=QV=kQ1Q2/rPotential Energy, 2 Charges23-1060423-8603
Q=CVCapacitance, Definition24-161424-1613
C=ε0A/dC of Parallel Plates24-261524-2614
Ceq=C1+C2Equivalent C, Parallel24-361824-3617
1/Ceq=1/C1+1/C2Equivalent C, Series24-461824-3617
U=½QVEnergy in a Capacitor24-562024-4620
u=½ε0Energy Density24-662124-4620
C=KC0Dielectric Constant24-762124-5621
I=dQ/dtCurrent, Definition25-163725-2636
V=IROhm’s Law25-263825-3638
∀(for all)R, W=0Vogon’s LawN/AN/AN/AN/A
R=ρl/AResistivity25-364025-4640
σ=1/ρConductivity25-464025-4640
P=IVElectric Power25-664225-5642
Pavg=½Ipeak²RAverage Power, ACN/A64525-7645
I=jACurrent Density25-1164725-8647
j=nqvdDrift Velocity25-1564825-8647
j=σEE, j, and σ25-1764925-8647
Req=R1+R2Resistors in Series26-266026-2660
1/Req=1/R1+1/R2Resistors in Parallel26-366126-2660
∑Iin=∑IoutJunction RuleN/A66526-3664
∑V=0 around a loopLoop RuleN/A66526-3664
τ=RC
Time Constant
N/A
670
26-4
696

Q=Cε(1-e-t/RC)
Charging Capacitor
26-5
670
26-4
696

F=Il×B
Wire in a Uniform Mag Field
27-3
691
27-3
689

F=qv×B
Charge in a Uniform M Field
27-5
692
27-4
692

μ=NIA
Magnetic Dipole Moment
27-10
696
27-5
695

τ=μ×B
Torque on a Loop
27-11
696
27-5
695

U=-μ×B, U=0@θ=π/2
Magnetic Poten Energy
27-12
696
27-5
695

B=μ0I/(2πr)
Mag Field, Straight Wire
28-1
710
28-1
710

μ0=4π·10-7T·m/A
Permeability of Free Space
N/A
710
28-1
710

dl0Iencl
Ampere’s Law
28-3
713
28-4
712

B=μ0nI
Mag Field in Solenoid
28-4
717
28-5
716

dB0Idl×r^/(4πr²)Biot-Savart Law
28-5
719
28-6
719

ΦB=∫dA
Magnetic Flux
29-1
736
29-2
736

ε=-dΦB/dt