IGCSE Physics: Electricity Concepts

Vocabulary flashcards covering static electricity, electric fields, current, potential difference, circuits, and resistance from IGCSE Physics lecture notes.

Electrostatic Charge

An electric charge acquired by certain materials when rubbed together, also known as static electricity.

Law of Electric Charges

The fundamental rule stating that like charges repel each other, whereas unlike charges attract each other.

Proton

A subatomic particle in the central nucleus of an atom carrying a positive charge equal in magnitude to an electron's negative charge.

Electron

A light subatomic particle orbiting the atomic nucleus carrying a negative electric charge.

Neutron

A subatomic particle located in the atomic nucleus that carries no electric charge.

Conductors

Materials, such as metals, that allow electrons to pass freely through them due to loosely held free electrons.

Insulators

Materials that hardly conduct electricity because their electrons are tightly held to atoms and are not free to move.

Semiconductors

'In-between' materials that act as poor conductors when cold, but become much better conductors when warm.

Induced Charges

Electric charges that appear on an uncharged object due to the presence of a nearby charged object without direct contact.

Earthing

Connecting an object to the ground using a conducting material so unwanted electric charge flows away safely.

Gold Leaf Electroscope

An instrument used to detect electrostatic charge, operating by the divergence of a gold leaf and metal plate when charges are induced.

Coulomb ($\text{C}$)

The SI unit of electric charge, equal to the charge on approximately 6 billion billion ($6 \times 10^{18}$) electrons.

Microcoulomb ($\nu\text{C}$)

A unit of charge equal to one millionth of a coulomb ($10^{-6 caravan\text{C}}$ or $1 \times 10^{-6}\text{C}$).

Electrostatic Precipitator

A device fitted to factory or power station chimneys that removes tiny ash particles from waste gases using electric charges.

Electric Field

A region in space where an electric charge experiences a force, represented by field lines pointing away from positive charges and towards negative charges.

Ion

An electrically charged atom or group of atoms formed when neutral atoms gain or lose electrons.

Electric Current

The rate of flow of electric charge through a conductor, defined mathematically as $I = \frac{Q}{t}$.

Ampere ($\text{A}$)

The SI unit of electric current, where $1\,\text{A}$ corresponds to a flow rate of one coulomb per second ($1\,\text{C/s}$).

Ammeter

A measuring instrument connected in series in a circuit to measure electric current.

Conventional Current Direction

The direction from the positive ($+\text{ve}$) terminal to the negative ($-\text{ve}$) terminal around a circuit, which is opposite to actual electron flow.

Potential Difference (p.d.)

The work done per unit of charge in driving charge through a component, calculated as $V = \frac{W}{Q}$.

Volt ($\text{V}$)

The SI unit of potential difference and e.m.f., where $1\,\text{V}$ corresponds to $1\,\text{J}$ of work done per $1\,\text{C}$ of charge transferred.

Electromotive Force (e.m.f.)

The maximum potential difference produced by a source (such as a cell) measured when it is driving charge round a complete circuit.

Voltmeter

An instrument connected in parallel across a component to measure potential difference.

Electrical Resistance

The opposition of a material or component to the flow of electric current, defined as $R = \frac{V}{I}$.

Ohm ($\Omega$)

The SI unit of electrical resistance.

Variable Resistor (Rheostat)

A circuit component whose resistance can be adjusted to vary the current flowing in a circuit.

Thermistor

A semiconductor component whose resistance decreases sharply as its temperature rises.

Light-Dependent Resistor (LDR)

A component that has high electrical resistance in dark conditions and low resistance when exposed to light.

Diode

A semiconductor component with extremely high resistance in the reverse direction but low resistance in the forward direction, allowing current to flow in one direction only.

Ohm's Law

The principle stating that electric current is directly proportional to potential difference for a metal conductor, provided its temperature remains constant.

Resistivity ($\rho$)

A characteristic material constant at a given temperature that determines resistance, expressed in the formula $R = \rho \times \frac{l}{A}$.