### Coulomb’s Law

Force between two point charges:

### Electric Fields

Definition of Electric Field:

For a single point:

### Potential and Voltage

Definition of electric potential V:

For a constant electric field:

Potential due to a point charge at distance a:

### Gauss’s Law

Gauss’s Law:

Electric Field due to an infinite plane of charge with charge density :

Electric Field due to an infinite line of charge with charge density :

### Circuit containing Batteries and Resistors

Definition of the magnitude of current:

Current density J:

Ohm’s law:

Resistivity:

Resistance:

Conductivity:

Energy:

### Capacitors

Definition of capaciance:

Capaciance of parallel plate with area A and distance d:

Energy:

Capaciance with Dielectrics:

### RC Circuits

#### Discharging a Capacitor through a Resistor

Charge:

Current:

#### Charging a Capacitor

Charge:

Current:

### Magnetic Fields

Force exerted on point charge by magnetic field:

Force exerted on a straight current-carrying wire:

Magnetic field due to a point charge:

Biot-Savart Law: Magnetic field due to a differential length of wire:

Magnetic field due to a infinitiely long wire:

Ampere’s Law:

### Faraday’s and Lenz’s Law:

Magnetic flux:

Faraday’s Law:

Farady’s Law and Electric field:

Lenz’s Law: The induced current produces a magnetic field which in turn produces a flux that opposes the change in flux in the loop caused by the changing external magnetic field.

### Inductors

Self-inductance: or

Energy:

#### RL Circuits(Resistor and Inductor)

Current decay:

Voltage decay:

Current growth:

Voltage decay:

#### LC Circuit(Capacitor and Inductor)

Capacitor’s charge:

Current:

Angular frequency:

Linear frequency:

Relationship between energy:

### Maxwell’s Equations

Gauss’s Law for electricity:

Gauss’s Law for magnetism:

Faraday’s Law:

Ampere-Maxwell Law: