Numbers
AQA A-Level Physics 7408
Measurements and Their Errors
Particles and Radiation
Topic overviewConstituents of the atomStable and unstable nucleiParticles, antiparticles and photonsParticle interactionsClassification of particlesQuarks and antiquarksApplications of conservation lawsThe photoelectric effectCollisions of electrons with atomsEnergy levels and photon emissionWave-particle duality
Waves
Mechanics and Materials
Electricity
Further Mechanics and Thermal Physics
Fields and Their Consequences
Topic overviewFieldsNewton's lawGravitational field strengthGravitational potentialOrbits of planets and satellitesCoulomb's lawElectric field strengthElectric potentialCapacitanceParallel plate capacitorEnergy stored by a capacitorCapacitor charge and dischargeMagnetic flux densityMoving charges in a magnetic fieldMagnetic flux and flux linkageElectromagnetic inductionAlternating currentsTransformers
Nuclear Physics
AstrophysicsOptional topic
Topic overviewAstronomical telescope consisting of two converging lensesReflecting telescopesSingle dish radio telescopes, I-R, U-V and X-ray telescopesAdvantages of large diameter telescopesClassification by luminosityAbsolute magnitude, MClassification by temperature, black-body radiationPrinciples of the use of stellar spectral classesThe Hertzsprung-Russell (HR) diagramSupernovae, neutron stars and black holesDoppler effectHubble's lawQuasarsDetection of exoplanets
Medical PhysicsOptional topic
Topic overviewPhysics of visionDefects of vision and their correction using lensesEar as a sound detection systemSensitivity and frequency responseDefects of hearingSimple ECG machines and the normal ECG waveformUltrasound imagingFibre optics and endoscopyMagnetic resonance (MR) scannerThe physics of diagnostic X-raysImage detection and enhancementAbsorption of X-raysCT scannerImaging techniquesHalf-lifeGamma cameraUse of high-energy X-raysUse of radioactive implantsImaging comparisons
Engineering PhysicsOptional topic
Turning Points in PhysicsOptional topic
Topic overviewCathode raysThermionic emission of electronsSpecific charge of the electronPrinciple of Millikan's determination of the electronic charge, eNewton's corpuscular theory of lightSignificance of Young's double slits experimentElectromagnetic wavesThe discovery of photoelectricityWave–particle dualityElectron microscopesThe Michelson-Morley experimentEinstein's theory of special relativityTime dilationLength contractionRelativistic mass and energy
ElectronicsOptional topic
Topic overviewMOSFET (metal-oxide semiconducting field-effect transistor)Zener diodePhotodiodeHall effect sensorDifference between analogue and digital signalsLC resonance filtersThe ideal operational amplifierInverting amplifier configurationNon-inverting amplifier configurationSumming amplifier configurationReal operational amplifiersCombinational logicSequential logicAstablesPrinciples of communication systemsTransmission mediaTime-division multiplexingAmplitude (AM) and frequency modulation (FM) techniques
Engineering Physics
- 12 subtopics
- 52 things to know
- Paper 3, section B
- Paper 3 Section B, one optional topic of five
What Engineering Physics covers
Engineering physics is one of the five optional topics, sat on Paper 3. It has two halves: rotational dynamics, which mirrors linear mechanics with moment of inertia in place of mass, and thermodynamics, which covers the gas processes and the engines built on them.
Where it is assessed
Paper 3, section B
One optional topic, chosen from five.
Check the AQA specification ↗The 12 subtopics
Each one has its own page.
- Concept of moment of inertiaMoment of inertia as resistance to angular acceleration, and why shape matters as much as mass.Open →
- Rotational kinetic energyThe ½Iω² formula, and the flywheel as an energy store.Open →
- Rotational motionAngular displacement, velocity and acceleration, the rotational equations of motion, and the graphs.Open →
- Torque and angular accelerationTorque as the rotational analogue of force, and T = Iα.Open →
- Angular momentumConservation of angular momentum, angular impulse, and the spinning skater.Open →
- Work and powerWork done by a torque, power transmitted by a rotating shaft, and the effect of friction.Open →
- First law of thermodynamicsQ = ΔU + W, the sign conventions, and isothermal and adiabatic changes.Open →
- Non-flow processesIsothermal, adiabatic, constant pressure and constant volume changes, and the work done in each.Open →
- The p–V diagramReading work from the area under a curve, cyclic processes, and the direction of the loop.Open →
- Engine cyclesThe four-stroke petrol and diesel cycles, indicator diagrams, and input, brake and friction power.Open →
- Second Law and enginesWhy a heat engine must reject heat, thermal efficiency, and the maximum theoretical efficiency.Open →
- Reversed heat enginesRefrigerators and heat pumps, the coefficient of performance, and why it can exceed one.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Why do a disc and a hoop of equal mass and radius differ in moment of inertia?
Key term
In rotational motion, what quantity plays the same role as mass does in linear motion?
Numbers
How is rotational kinetic energy calculated, and what does I represent?
Process
How does stored energy depend on angular velocity, and what limits a flywheel's speed?
Numbers
Explain why centripetal stresses in a flywheel increase with rotational speed
Process
What is angular displacement, and how does angular speed differ from angular velocity?
Numbers
How is angular velocity calculated, what is angular acceleration, and how does angular speed differ from angular velocity?
Numbers
What do the gradients of the angular displacement and angular velocity graphs give?
Numbers
Why does the slope of an ω–t graph give angular acceleration, how is its instantaneous value found, and what does the area under the graph give?
Numbers
What does ω₂ = ω₁ + αt relate, and what do curved and straight graph lines indicate?
Numbers
When is ω₂² = ω₁² + 2αθ used, and what are the translational analogues?
Numbers
What is torque, and how does it relate to moment of inertia and angular acceleration?
Numbers
What do the terms in T = Iα mean, and how does it parallel F = ma?
Numbers
What unit does torque take, what does a net torque cause, and what does r mean in T = Fr?
Numbers
How is angular momentum defined, and when is it conserved?
Numbers
What is angular impulse, and how does it relate to change in angular momentum?
Numbers
When does TΔt = Δ(Iω) apply, and why does a skater spin faster with arms pulled in?
Numbers
How is final angular velocity found after an impulse, and how does a gymnast use this?
Numbers
How is work done by a torque calculated, and what unit does it take?
Numbers
How is power transmitted by a rotating shaft calculated, and what reduces useful output?
Key term
Where does frictional torque typically arise in rotating machinery?
Numbers
What does the first law of thermodynamics state, and what does Q represent?
Numbers
What do W and ΔU represent, and which wider principle does the first law apply?
Numbers
What sign does W take when a gas expands, and when it is compressed?
Numbers
What is the first law rearranged for ΔU, and what sign does Q take when a system gains, then loses, energy by heating?
Numbers
What happens to internal energy in an isothermal change, and what defines an adiabatic one?
Numbers
What is the ideal gas equation, and what is ΔV in a constant volume process?
Numbers
What do p and R represent in the gas equation, and what holds for an adiabatic change?
Numbers
How is work at constant pressure calculated, and what stays fixed in an isothermal change?
Numbers
In an adiabatic change how does work relate to ΔU, what work is done at constant volume, and where does heat supplied at constant volume go?
Process
What happens to the temperature of a gas during an adiabatic expansion?
Key term
During an adiabatic compression, is work done on the gas or by the gas?
Numbers
What do the symbols in W = pΔV mean, and what does an anticlockwise loop indicate?
Process
What is a cyclic process, how is the work done in a single process found from a p–V diagram, and how is the net work per cycle found?
Process
If a cyclic process traces a clockwise loop on a p–V diagram, is net work done by the gas or on the gas?
Numbers
How is input power calculated, and what is calorific value?
Numbers
What is the brake power formula, what do its symbols mean, and how is friction power defined?
Numbers
What does overall efficiency measure, and what does friction power represent?
Numbers
How are thermal and mechanical efficiency calculated, and what does the latter represent?
Key term
In a four-stroke engine, how many crankshaft revolutions are required for each cylinder to complete one power stroke?
Key term
How can indicator diagrams be used to assess efficiency losses in a real engine?
Numbers
How is the efficiency of a heat engine defined and calculated?
Numbers
What sets the maximum theoretical efficiency, and what temperature scale must be used?
Key term
Why must a heat engine reject heat, and where does QH come from?
Numbers
What would happen to the maximum theoretical efficiency of a heat engine if the cold reservoir temperature could be reduced to absolute zero?
Process
In a CHP scheme, how is the heat that would otherwise be wasted (QC) used?
Numbers
How is the coefficient of performance of a refrigerator defined, and what is Q_C?
Numbers
When does the temperature-based COP formula apply, and what is Qₕ?
Numbers
How is heat pump COP calculated, and what scale must temperatures use?
Numbers
Why must Celsius not be used in COP formulae, and why can COP exceed one?
Numbers
What is a heat pump's ideal COP in terms of temperatures, why does it deliver more energy than the work put in, and why is a COP above one no breach of energy conservation?
Take Engineering Physics further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Torque vs Power
Torque: turning effect of a force about an axis. Power: rate of energy transfer.
Elastic collision vs Inelastic collision
Elastic collision: total kinetic energy conserved. Inelastic collision: total kinetic energy not conserved.
Heat engine vs Refrigerator
Heat engine: device converting thermal energy into work. Refrigerator: device using work to transfer heat from cold to hot.
Questions from this topic
Each one with the model answer underneath.
- 1
State the formula for the moment of inertia of a point mass.
Model answer
I = mr², where I is moment of inertia, m is mass, and r is the perpendicular distance from the axis of rotation.
- 2
Define the moment of inertia of a point mass in words.
Model answer
The moment of inertia of a point mass is the product of its mass and the square of its perpendicular distance from the axis of rotation.
- 3
What does the symbol r represent in the equation I = mr² for a point mass?
Model answer
The perpendicular distance from the mass to the axis of rotation.
- 4
Calculate the moment of inertia when mass = 3.6 kg, distance from axis = 0.4 m.
Model answer
Moment of inertia = 3.6 × 0.4 × 0.4 = 0.576 kg m².
- 5
State the formula for the moment of inertia of an extended object.
Model answer
I = Σmr², where the sum is taken over all constituent mass elements, each multiplied by the square of its perpendicular distance from the axis of rotation.
- 6
Explain why the moment of inertia of an extended object is calculated as a summation rather than a single product.
Model answer
An extended object consists of many mass elements at different distances from the axis, so each element's contribution (mr²) must be summed to find the total moment of inertia.
What is inside Levo
Six ways to work the same material.
Engineering Physics revision questions
- What does Engineering Physics cover in AQA A-Level Physics?
- 12 subtopics: concept of moment of inertia, rotational kinetic energy, rotational motion, torque and angular acceleration, angular momentum, work and power, first law of thermodynamics, non-flow processes, the p–v diagram, engine cycles, second law and engines and reversed heat engines. Each one has its own page with questions and model answers.
- How is Engineering Physics organised?
- By the AQA 7408 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Engineering Physics, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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