Electrical Quantities Vocabulary Flashcards

A set of vocabulary flashcards covering electric charges, fields, conductors, insulators, current, voltage, resistance, and electrical energy from CIE IGCSE Physics.

Electric Charge

A fundamental property of subatomic particles that can be positive or negative, measured in units called coulombs ($C$).

Charging by Friction

The process by which insulating solids become electrically charged when rubbed together, resulting in one material gaining electrons and the other losing electrons.

Gold-leaf Electroscope

A device consisting of a metal plate, a metal stem, and a thin gold leaf housed in an airtight container, used to detect electric charge.

Electric Field

A region of space in which an electric charge experiences a force, with a direction defined as the direction of force on a positive charge at that point.

Point Charge Electric Field Pattern

An electric field layout where field lines are directed radially outwards from a positive point charge ($+$) and radially inwards towards a negative point charge ($-$).

Uniform Electric Field

An electric field between two parallel oppositely charged plates where field lines are parallel, equally spaced straight lines directed from the positive plate to the negative plate.

Electrical Conductor

A material (such as copper or steel) that allows charge to flow through it easily because it contains delocalised electrons free to move through a metallic lattice.

Electrical Insulator

A material (such as rubber, plastic, or glass) that has no free charges and therefore does not allow charge to flow through it easily.

Electric Current

The rate of flow of electric charge per unit time ($I = \frac{Q}{t}$), measured in amperes ($A$), where $1\,A = 1\,C/s$.

Conventional Current

The flow of positive charge from the positive terminal to the negative terminal of a power source, which is opposite to the flow of electrons.

Direct Current (d.c.)

A steady electric current that continuously flows in a single direction around a circuit, typically produced by cells and batteries.

Alternating Current (a.c.)

An electric current that continuously changes its direction back and forth around a circuit, produced by electrical generators.

Electromotive Force (e.m.f.)

The electrical work done by a source in moving a unit charge around a complete circuit ($E = \frac{W}{Q}$), measured in volts ($V$).

Potential Difference (p.d.)

The work done by a unit charge passing through a component ($V = \frac{W}{Q}$), measured in volts ($V$), where $1\,V = 1\,J/C$.

Resistance

The opposition to the flow of electric current caused by collisions between flowing electrons and vibrating metal ions in a conductor, measured in ohms ($\Omega$).

Ohm's Law

The law stating that current through a conductor is directly proportional to potential difference and inversely proportional to resistance ($R = \frac{V}{I}$).

Ohmic Resistor

A component with constant resistance whose current-voltage ($I\text{-}V$) graph is a linear straight line passing through the origin.

Non-ohmic Resistor

A component (such as a filament lamp or diode) whose resistance changes with voltage, current, or temperature, resulting in a non-linear current-voltage graph.

Diode

A semiconductor component that allows electric current to flow in one direction only (forward bias) while presenting very high resistance in the reverse direction (reverse bias).

Resistance Proportionality in Wires

The relationship where a wire's resistance ($R$) is directly proportional to its length ($L$) ($R \propto L$) and inversely proportional to its cross-sectional area ($A$) ($R \propto \frac{1}{A}$).

Electrical Power

The rate at which electrical energy is transferred or dissipated by an appliance ($P = \frac{E}{t}$ or $P = I V$), measured in watts ($W$).

Kilowatt-hour (kW h)

A unit of electrical energy equivalent to $3.6 \times 10^6\,J$, calculated by multiplying power in kilowatts ($kW$) by time in hours ($h$).