Electricity and Magnetism Lecture Notes

A set of vocabulary flashcards covering key concepts in Electricity and Magnetism.

Matter

Anything that occupies space and has mass.

Law of Impenetrability

No two things can occupy the same space at the same time.

Element

A substance that cannot be reduced to a simpler substance by chemical means.

Compound

A substance that resulted from two or more elements chemically combined.

Mixture

A combination of elements and compounds that are not chemically combined.

Atom

The smallest particle of an element that retains the characteristics of that element.

Molecule

A chemical combination of two or more atoms.

Atomic Number

The number of protons contained in the nucleus of an atom.

Electric Field

The force per unit positive charge that would be experienced by a stationary point charge in a given location in a field.

Electric Current

Any directional movement of electric charges such as electrons.

Voltage

The difference in potential between two points that represents the work done in the transfer of a unit quantity of electricity.

Resistance

The property of a material to oppose or limit the flow of current or charge.

Capacitance

The ability of a system to store electric charge.

Inductance

The property of a circuit whereby there is an electromotive force induced into the circuit by the change of flux linkages.

Magnetism

The phenomenon whereby a substance attracts pieces of iron.

Magnetomotive Force (mmf)

Magnetic potential, analogous to voltage, measured in Ampere-Turns (At).

Magnetic Field Intensity (H)

The intensity that depends on the length of the coil.

Magnetic Flux (φ)

The total number of magnetic lines of force leaving or entering the pole of a magnet.

Flux Density (B)

The number of magnetic field lines per unit area perpendicular to the direction of flux.

Valence Electrons

Electrons in the outermost shell of an atom that determine its chemical and electrical properties.

Conductor

A material that allows the easy flow of electric current due to its high density of free electrons.

Insulator

A material that resists the flow of electric current because its electrons are tightly bound to its atoms.

Semiconductor

A material with electrical conductivity between that of a conductor and an insulator.

Coulomb (C)

The basic unit of electric charge, equal to the charge of approximately 6.24 \times 10^{18} electrons.

Ampere (A)

The unit of electric current equivalent to one Coulomb per second (1\text{ A} = 1\text{ C/s}).

Ohm (\Omega)

The unit of electrical resistance.

Reluctance (\mathcal{R})

The opposition a material offers to the creation of magnetic flux, analogous to electrical resistance.

Permeability (\mu)

The measure of a material's ability to support the formation of a magnetic field within itself.

Ion

An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

Isotope

Atoms of the same element that have the same number of protons but a different number of neutrons.

Ohm's Law

The fundamental relationship between voltage (V), current (I), and resistance (R): V = I \times R.

Electric Power (P)

The rate at which electrical energy is consumed or converted, expressed as P = V \times I.

Joule (J)

The standard unit of energy or work in the SI system.

Watt (W)

The SI unit of power, equivalent to one Joule per second (1\text{ W} = 1\text{ J/s}).

Series Circuit

A configuration where components are connected in a single path so that the same current flows through all parts.

Parallel Circuit

A configuration where components are connected across the same voltage source, providing multiple paths for current flow.

Faraday's Law of Induction

A law stating that a change in magnetic flux through a conductor induces an electromotive force (EMF).

Lenz's Law

A law stating that the direction of an induced current always opposes the change in magnetic flux that produced it.

Permeance (\mathcal{P})

The reciprocal of reluctance, representing the ease with which magnetic flux passes through a material.

Residual Magnetism

The magnetism that remains in a ferromagnetic material after the external magnetizing force is removed.

Hysteresis

The delay or lagging of the magnetic induction (B) behind the magnetizing force (H).

Coercivity

The intensity of the magnetic field required to reduce the residual magnetism of a material to zero.

Proton

A subatomic particle with a positive electric charge found within the nucleus of an atom.

Neutron

A subatomic particle with no electric charge (neutral) found within the nucleus of an atom.

Electron

A subatomic particle with a negative electric charge that orbits the nucleus of an atom in specific energy levels or shells.

Conductance (G)

The measure of how easily electricity flows through a component; it is the reciprocal of resistance, defined as G = \frac{1}{R}.

Siemens (S)

The SI unit of electric conductance.

Kirchhoff's Current Law (KCL)

A fundamental law stating that the algebraic sum of currents entering a junction (node) is equal to zero.

Kirchhoff's Voltage Law (KVL)

A fundamental law stating that the algebraic sum of all voltages around any closed loop in a circuit is equal to zero.

Ferromagnetic Materials

Materials that exhibit strong magnetic properties and can be easily magnetized, such as iron, cobalt, and nickel.

Paramagnetic Materials

Materials that are weakly attracted to a magnetic field and do not retain magnetic properties once the external field is removed.

Diamagnetic Materials

Materials that create an opposing magnetic field when placed in an external magnetic field, resulting in a weak repulsion.

Electromotive Force (EMF)

The electrical action produced by a non-electrical source (like a battery) that provides the energy to move charges through a circuit.

Potential Difference

The difference in electrical potential energy between two points in a circuit, commonly referred to as voltage.

Mutual Inductance

The property by which a change of current in one conductor or coil induces a voltage in another nearby conductor or coil through magnetic coupling.