Phenomena associated with electrical charges and currents, and the study of such phenomena. Between collections of positive and negative charges there exists a potential difference. If a conducting path exists between the two charge groups, charges will flow from one to the other, constituting an electric current. Electric charge which builds up on an insulator and is thus unable to flow is termed static electricity.
| Electromagnetism | |
| Magnetism | |
| Electrostatics | |
|---|---|
| Electric charge | |
| Coulomb's law | |
| Electric field | |
| Gauss's law | |
| Electric potential | |
| Magnetostatics | |
| Ampere's law | |
| Magnetic field | |
| Magnetic moment | |
| Electrodynamics | |
| Electric current | |
| Lorentz force law | |
| Electromotive force | |
| Electromagnetic induction | |
| Faraday-Lenz law | |
| Displacement current | |
| Maxwell's equations | |
| Electromagnetic field | |
| Electromagnetic radiation | |
| Electrical circuits | |
| Electrical conduction | |
| Electrical resistance | |
| Capacitance | |
| Inductance | |
| Impedance | |
| Resonant cavities | |
| Waveguides | |
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Electricity (from Greek ήλεκτρον (electron) "amber") is a general term for the variety of phenomena resulting from the presence and flow of electric charge. Similarly, there is an electric potential at every point in space, and its gradient indicates the direction and magnitude of the driving force behind charge movement
Electric current
An electric current is a flow of electric charge, and its intensity is measured in amperes.
SI electricity units
| edit SI electromagnetism units | ||||
|---|---|---|---|---|
| Symbol | Name of Quantity | Derived Units | Unit | Base Units |
| I | Magnitude of current | ampere (SI base unit) | A | A = W/V = C/s |
| q | Electric charge, Quantity of electricity | coulomb | C | A·s |
| V | Potential difference or Electromotive force | volt | V | J/C = kg·m·A−1 |
| R, Z, X | Resistance, Impedance, Reactance | ohm | Ω | V/A = kg·m·A−2 |
| ρ | Resistivity | ohm metre | Ω·m | kg·m·A−2 |
| P | Power, Electrical | watt | W | V·A = kg·m |
| C | Capacitance | farad | F | C/V = kg·A |
| Elastance | reciprocal farad | F−1 | V/C = kg·m·s−4 | |
| ε | Permittivity | farad per metre | F/m | kg·A |
| χe | Electric susceptibility | (dimensionless) | - | - |
| G, Y, B | Conductance, Admittance, Susceptance | siemens | S | Ω·m·A2 |
| σ | Conductivity | siemens per metre | S/m | kg·s |
| H | Magnetic field, magnetic field intensity | ampere per metre | A/m | A·m−1 |
| Φm | Magnetic flux | weber | Wb | V·s = kg·m·A−1 |
| B | Magnetic flux density, magnetic induction, magnetic field strength | tesla | T | Wb/m·A−1 |
| Reluctance | ampere-turn per weber | A/Wb | kg·s | |
| L | Inductance | henry | H | Wb/A = V·s/A = kg·m·A−2 |
| μ | Permeability | henry per metre | H/m | kg·m·s |
| χm | Magnetic susceptibility | (dimensionless) | - | - |
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