AQA GCSE Combined Science: Trilogy — Physics Paper 1 Flashcards

Comprehensive vocabulary and equation flashcards for AQA GCSE Combined Science: Trilogy Physics Paper 1 covering Energy, Electricity, Particle Model of Matter, and Atomic Structure & Radiation.

Conservation of Energy

A foundational law stating that energy cannot be created or destroyed, only transferred usefully, stored, or dissipated.

Closed System

A system where no energy or matter can enter or leave, meaning the net change in energy is zero.

Kinetic Energy Equation

$E_k = \frac{1}{2} m v^2$, where $m$ is mass in $\text{kg}$, $v$ is speed in $\text{m/s}$, and $E_k$ is kinetic energy in Joules ($\text{J}$).

Gravitational Potential Energy Equation

$E_p = m g h$, where $m$ is mass in $\text{kg}$, $g = 9.8Server N/kg$, $h$ is height in $\text{m}$, and $E_p$ is gravitational potential energy in Joules ($\text{J}$).

Power

The rate of energy transfer or rate of work done, calculated as $P = \frac{E}{t}$ or $P = \frac{W}{t}$, where $P$ is power in Watts ($\text{W}$).

Efficiency Equation

$\text{Efficiency} = \frac{\text{Useful Output Energy Transfer}}{\text{Total Input Energy Transfer}}$ or $\frac{\text{Useful Power Output}}{\text{Total Power Input}}$.

Elastic Potential Energy Equation

$E_e = \frac{1}{2} k e^2$, where $k$ is the spring constant in $\text{N/m}$ and $e$ is extension in $\text{m}$.

Change in Thermal Energy Equation

$\text{Δ}E = m c \text{Δ}\theta$, where $c$ is specific heat capacity in $\text{J/kg}^\text{∘}\text{C}$ and $\text{Δ}\theta$ is temperature change in ${}^\text{∘}\text{C}$.

Wasted Energy

Unwanted energy transfers that dissipate into the surroundings, usually as thermal energy.

Lubrication

A method used to reduce friction between moving parts, thereby reducing wasted thermal energy.

Thermal Conductivity

A measure of how quickly energy is transferred through a material by conduction, where higher conductivity results in a faster rate of energy transfer.

Renewable Energy Resources

Energy resources that will never run out and are generally clean (e.g., wind, solar, hydroelectric, geothermal, tidal, biofuel, waves), though they can be unreliable.

Non-Renewable Energy Resources

Energy resources with a finite supply that are reliable but cause environmental damage (e.g., fossil fuels releasing $\text{CO}_2$ and $\text{SO}_2$, and nuclear power producing radioactive waste).

Current

The flow of electrical charge per second, symbolized by $I$ and measured in Amperes ($\text{A}$) using an ammeter connected in series.

Potential Difference

The driving force or energy transferred per unit charge, symbolized by $V$ and measured in Volts ($\text{V}$) using a voltmeter connected in parallel.

Resistance

The opposition to current flow in an electrical circuit, symbolized by $R$ and measured in Ohms ($\text{Ω}$).

Charge Flow Equation

$Q = I t$, where $Q$ is charge in Coulombs ($\text{C}$), $I$ is current in Amperes ($\text{A}$), and $t$ is time in seconds ($\text{s}$).

Potential Difference Equation

$V = I R$, where $V$ is potential difference in Volts ($\text{V}$), $I$ is current in Amperes ($\text{A}$), and $R$ is resistance in Ohms ($\text{Ω}$).

Electrical Power Equations

$P = V I$ and $P = I^2 R$, where $P$ is power in Watts ($\text{W}$).

Electrical Energy Transferred Equations

$E = P t$ and $E = Q V$, where $E$ is energy in Joules ($\text{J}$).

Series Circuit Rules

Current is identical everywhere ($I_1 = I_2 = I_3$), total potential difference is shared ($V_{\text{total}} = V_1 + V_2 + \text{…}$), and total resistance adds up ($R_{\text{total}} = R_1 + R_2 + \text{…}$).

Parallel Circuit Rules

Current is shared across branches ($I_{\text{total}} = I_1 + I_2 + \text{…}$), potential difference is identical across components ($V_1 = V_2 = \text{…}$), and adding resistors in parallel reduces total resistance.

Ohmic Conductor

A component in which current is directly proportional to potential difference, possessing constant resistance and a straight-line I-V graph passing through the origin.

Filament Lamp

A component whose resistance increases as its temperature increases, producing an S-shaped I-V characteristic curve.

Diode

A component that permits current flow in one direction only due to extremely high resistance in the reverse direction.

LDR (Light Dependent Resistor)

A component whose electrical resistance decreases as light intensity increases.

Thermistor

A component whose electrical resistance decreases as temperature increases.

UK Mains Electricity

An alternating current ($\text{AC}$) supply delivered at $230\text{ }\text{V}$ and a frequency of $50\text{ }\text{Hz}$.

Live Wire

The brown wire in a standard UK plug that carries $230\text{ }\text{V}$ alternating potential difference from the supply and is dangerous to touch even when switched off.

Neutral Wire

The blue wire in a standard UK plug that completes the circuit, held at $0\text{ }\text{V}$.

Earth Wire

The green/yellow safety wire in a standard UK plug held at $0\text{ }\text{V}$ that carries current safely into the ground if a fault occurs.

Density Equation

$\text{ρ} = \frac{m}{V}$, where $\text{ρ}$ is density in $\text{kg/m}^3$ or $\text{g/cm}^3$, $m$ is mass in $\text{kg}$ or $\text{g}$, and $V$ is volume in $\text{m}^3$ or $\text{cm}^3$.

Internal Energy

The total kinetic energy and potential energy stored by all the particles that make up a system.

Specific Latent Heat Equation

$E = m L$, where $L$ is the Specific Latent Heat in $\text{J/kg}$ required to change the state of $1\text{ }\text{kg}$ of a substance with no change in temperature.

Specific Latent Heat of Fusion

The energy required per kilogram to change a substance between solid and liquid states without changing its temperature.

Specific Latent Heat of Vaporisation

The energy required per kilogram to change a substance between liquid and gas states without changing its temperature.

Atomic Radius

The approximate size of an atom, equal to roughly $1 \times 10^{-10}\text{ }\text{m}$.

Isotopes

Atoms of the same element containing the same number of protons but different numbers of neutrons.

Plum Pudding Model

An early atomic model proposed by JJ Thomson describing the atom as a sphere of positive charge with negative electrons embedded inside.

Alpha Scattering Experiment

Rutherford's experiment firing alpha particles at thin gold foil, revealing that the atom is mostly empty space with a dense, positively charged nucleus at the centre.

Alpha Radiation (α)

Nuclear radiation consisting of a helium nucleus ($2\text{ }\text{protons} + 2\text{ }\text{neutrons}$), having high ionising power and low penetration (stopped by paper or skin).

Beta Radiation (β)

Nuclear radiation consisting of a fast-moving electron, having medium ionising power and medium penetration (stopped by $5\text{ }\text{mm}$ of Aluminium).

Gamma Radiation (γ)

Nuclear radiation consisting of an electromagnetic wave/photon, having low ionising power and high penetration (absorbed by thick lead or concrete).

Half-Life

The time taken for half of the radioactive nuclei in a sample to decay, or for the count rate of a sample to fall to half its initial value.

Irradiation

The process of exposing an object to radiation without causing the object itself to become radioactive.

Contamination

The unwanted presence of radioactive materials on or inside an object or body, posing a high risk of ionising living tissue.