Form 8 Science: Electricity and Magnetism

Comprehensive vocabulary flashcards covering static electricity, circuit components and symbols, electric current, voltage, series and parallel circuits, Ohm's law, magnetism, and electromagnets.

Atom

The basic unit of matter that makes up everything in existence, containing subatomic particles called protons, neutrons, and electrons, with zero net electrical charge when neutral.

Subatomic Particles

Particles smaller than an atom: positively charged protons and uncharged neutrons bound within the nucleus, and negatively charged electrons that surround the nucleus.

Electrostatic Force

A non-contact force that causes oppositely charged objects to attract each other and objects with identical charges to repel each other without needing to touch.

Static Electricity

An imbalance of electric charges within or on the surface of an insulating material, where transferred charge remains stationary until it is discharged or conducted away.

Electrical Insulator

A material in which electric current does not flow freely, preventing transferred electrons from moving and allowing electrostatic charge to remain static.

Electrical Conductor

A material containing free electrons in its structure that allows electric charge to flow freely through it, preventing the buildup of static charge.

Lightning

A massive electrostatic discharge caused by charge separation from friction between clouds and air, creating an attraction between negative charges at the base of the clouds and positive charges on the ground or within other clouds.

Electric Circuit

A continuous closed loop with no gaps through which electric charges can move from place to place.

Cell

A circuit component that stores chemical energy and acts as the energy source that pushes electric charges around a circuit.

Battery

An electrical power source consisting of two or more cells joined together in series (positive terminal connected to negative terminal).

Switch

A circuit control component that must be closed to complete the circuit and allow electricity to flow, or opened to break the circuit and stop the current.

Electric Current ($I$)

The rate of flow of electric charge, defined as the amount of charge that flows past a given point in a circuit per second.

Rope Model

A physical analogy for an electric circuit where a continuous loop of rope represents circuit charges, pulling the rope represents the battery's push, and the amount of rope passing a point per second represents electric current.

Ammeter

An instrument designed to measure electric current in amperes ($\text{A}$), which must always be connected in series with the component being measured.

Voltage (Potential Difference)

The difference in electrical potential energy between two points that drives current flow, representing the energy transferred to a component per unit charge ($\text{V}$).

Voltmeter

An instrument designed to measure electrical potential difference or voltage in volts ($\text{V}$), which must always be connected in parallel across the component being measured.

Series Circuit

A circuit layout offering a single path for electric current, in which the current is identical at all points ($I_1 = I_2 = I_3$) and the total voltage is shared among components ($V_{\text{total}} = V_1 + V_2 + V_3$).

Parallel Circuit

A circuit layout containing multiple branches, where each component receives the full source voltage ($V_{\text{total}} = V_1 = V_2 = V_3$) and the total current is divided between the branches ($I_{\text{total}} = I_1 + I_2 + I_3$).

Electrical Resistance ($R$)

A measure of how strongly a component or wire opposes the flow of electrons through it, measured in ohms ($\Omega$).

Ohm's Law

The relationship stating that electrical resistance equals voltage divided by electric current: $\text{resistance} = \frac{\text{voltage}}{\text{electric current}}$ ($R = \frac{V}{I}$).

Short Circuit

A low-resistance path in an electrical circuit that bypasses the normal load or components, causing current to take the path of least resistance so components like lamps do not light up.

Fixed Resistor

An electrical component engineered to provide a set resistance value to control the amount of current passing through a section of a circuit, often identified by colored bands.

Line of Best Fit Gradient (Resistance Graph)

The calculated slope from a graph plotting voltage on the y-axis against electric current on the x-axis, determined by $\text{gradient} = \frac{y_2 - y_1}{x_2 - x_1}$, which yields the resistance ($R$) of the fixed resistor.

Electrical Metric Prefixes (kilo and milli)

Standard unit prefixes where kilo ($\text{k}$) denotes a factor of $1000$ ($1\text{ k}\Omega = 1000\,\Omega$) and milli ($\text{m}$) denotes a factor of $\frac{1}{1000}$ ($1\text{ mA} = 0.001\text{ A}$).

Magnetite

A naturally occurring magnetic rock, originally discovered according to legend by the shepherd Magnes in Ancient Greece near Magnesia ad Sipylum.

Magnetic Materials

The four specific elements and alloys attracted to a magnet that can be temporarily magnetized: iron, steel, nickel, and cobalt.

Magnetic Field

The region of space surrounding a magnet where magnetic materials or other magnets experience a magnetic force, visualized using iron filings or plotting compasses.

Electromagnet

A temporary magnet created by passing an electric current through a coil of wire wrapped around a magnetic core (such as an iron nail), producing a magnetic field that can be turned on and off.