FORMULA SHEET
Constants and definitions: 
; 
; 1 ampere (A) = 1 C/s; 1 volt (V) = 1 J/C; 1 farad (F) = 1
C/V; 1 ohm 
= 1 V/A; 1 tesla (T) = 1 N/(A m); 1 weber (Wb) = 1 T m2 = 1 J/A; and 1 henry
(H) = Wb/A = 1 J/A2.
.
Gauss’ law: 
.
Ohm’s law: 
or 
. 
Conservation of energy law (Kirchhoff’s loop
rule): 
around a closed loop.
Conservation
of charge law (Kirchhoff’s junction rule): Charge cannot be created or destroyed.
The current flowing into a junction equals the current flowing out.
Electric
Field:
Force on charge Q: 
.
Electric potential: 
.
Group of point charges: 
.
Continuous charge: 
.
Electric
Potential:
Potential energy of a charge Q: 
.
Electric field: 
.
Constant E: 
Group of point charges: 
.
Continuous charge: 
.
Work: Work-Energy theorem: 
.
Conservative force: 
.
Potential energy of a capacitor: 
.
Energy density: 
.
Power: 
emf: 
Force:
Coulomb’s: 
.
Lorentz: 
Conductor in electrostatic equilibrium: 1. The electric field
is zero everywhere. 2. Excess charge resides on the surfaces. 3. The electric
field is perpendicular to the surface.
Capacitance: 
.
n capacitors in parallel: 
.
n capacitors in series: 
.
RC Circuit:
capacitive time: 
charging a capacitor: 
.
discharging a capacitor: 
.
Resistance: 
.
n resistors in series: 
.
n resistors in parallel: 
.
power: 
.
Current: 
.
Flux: 
