Numbers
Edexcel GCSE Combined Science Physics 1SC0
Key Concepts of Physics
Motion and Forces
Topic overviewScalar and vector quantitiesExamples of vectors and scalars, and velocitySpeed, distance, time and distance-time graphsAcceleration and the equation v squared minus u squaredVelocity-time graphs and free fallMeasuring speed in the laboratory, and typical everyday speedsNewton's first law, and investigating force, mass and accelerationNewton's second and third lawsWeight, mass and gravitational field strengthReaction time, stopping distance and large decelerationsFactors affecting stopping distance and reaction time
Conservation of Energy
Waves
Light and the Electromagnetic Spectrum
Topic overviewProperties of electromagnetic wavesInvestigating refraction in glass blocksThe groups of the electromagnetic spectrumThe continuous spectrum, and what our eyes can detectHow radiation is generated, and why danger rises with frequencyHarmful effects of excessive exposure to radiationUses of electromagnetic radiation
Radioactivity
Topic overviewThe atom and the size of atomsIsotopes, atomic number and mass numberRelative masses and charges of subatomic particlesElectron orbits and energy levelsForming ions, and how the atomic model changedTypes of ionising radiationBackground radiation and detecting radioactivityAlpha, beta and gamma, and their penetrating powerBeta-minus and beta-plus decayEffects of decay on atomic number and mass numberBalancing nuclear equationsActivity and the becquerelHalf-life and the randomness of decayHalf-life calculationsThe dangers of ionising radiationSafety precautions, contamination and irradiation
Energy – Forces Doing Work
Topic overviewEnergy stores and energy transfer diagramsChanging a system's energy, and measuring work doneWork done and the energy changes it causesGravitational potential and kinetic energy calculationsDissipation and wasted energyPower as the rate of energy transferThe watt, and calculating efficiency
Forces and Their Effects
Electricity and Circuits
Topic overviewThe atom, and drawing circuit diagramsSeries and parallel circuitsPotential difference and the voltmeterEnergy transferred by moving chargeCurrent, charge and measuring currentResistance and the equation V = IRResistors in series and in parallelDesigning circuits to test componentsInvestigating resistance in circuitsCurrent-potential difference graphs for componentsLight-dependent resistors and thermistorsThe heating effect of an electric currentUses of the heating effect, and the equation E = IVtPower as energy transferred per secondCalculating electrical powerEnergy transfer in domestic devices, and power ratingsDirect and alternating currentAlternating current and the UK mains supplyLive and neutral wires, earthing and fusesFuses in the live wire, mains voltages and electrical dangers
Magnetism and the Motor Effect
Electromagnetic Induction
Particle Model
Topic overviewKinetic theory and differences in densityCalculating density, and investigating itChanges of state and internal energySpecific heat capacitySpecific latent heat and thermal insulationInvestigating the specific heat capacity of waterGas pressure and the motion of particlesAbsolute zero and the kelvin scale
Conservation of Energy
Calculating efficiency
- 3 things to know
- Paper 5
Overview
The efficiency equation, why efficiency has no unit, and calculating efficiency as a decimal or a percentage, the useful energy transferred, the total energy supplied and the energy wasted by devices, lamps and kettles.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
A device is supplied with 120 J and usefully transfers 30 J. Calculate its efficiency.
Numbers
A lamp is supplied with 200 J and transfers 15 J as light. Calculate its efficiency as a percentage.
Questions from this subtopic
Each one with the model answer underneath.
- 1
State the equation used to calculate the efficiency of a device.
Model answer
Efficiency = useful energy transferred by the device ÷ total energy supplied to the device.
- 2
Explain why efficiency has no unit.
Model answer
It is the ratio of two energies, so the units cancel.
- 3
A device is supplied with 120 J and usefully transfers 30 J. Calculate its efficiency.
Model answer
Efficiency = 30 ÷ 120 = 0.25.
- 4
A lamp is supplied with 200 J and transfers 15 J as light. Calculate its efficiency as a percentage.
Model answer
Efficiency = (15 ÷ 200) × 100 = 7.5%.
- 5
A device with an efficiency of 0.8 is supplied with 500 J. Calculate the useful energy it transfers.
Model answer
Useful energy = 0.8 × 500 = 400 J.
- 6
A machine usefully transfers 90 J and has an efficiency of 0.6. Calculate the total energy supplied to it.
Model answer
Total energy = 90 ÷ 0.6 = 150 J.
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