Key term
CCEA A-Level Physics 1210
Physical Quantities, Scalars and Vectors
Moments and Equilibrium
Linear Motion and Dynamics
Newton's Laws of Motion
Linear Momentum and Impulse
Work, Energy and Power
Current, Charge and Potential Difference
Resistance and Resistivity
Topic overviewResistance and Ohm's lawOhmic and non-ohmic behaviourResistors in series and in parallelInvestigating current, voltage and resistance in series and parallel circuitsElectrical power and energy in resistive circuitsResistivity and the equation R = ρl/AMeasuring the resistivity of a metalCurrent–voltage characteristics of a conductor, a lamp and a diodeResistance, temperature and superconductivity
Internal Resistance and Potential Dividers
Topic overviewInternal resistance and terminal potential differenceConsequences of internal resistance for external circuitsMeasuring electromotive force and internal resistanceThe potential divider and variable outputPotential dividers in lighting and heating control circuitsLoaded potential dividers and output voltage calculations
Waves
Refraction
Lenses
Superposition, Interference and Diffraction
Topic overviewSuperposition of wavesStanding waves, nodes and antinodesStanding waves on stretched stringsStanding waves in a pipe closed at one endMeasuring the speed of sound with a resonance tubeConditions for observable interferencePath difference and phase differenceYoung's double slitDiffraction at a single slitThe diffraction grating
Quantum Physics
Wave-Particle Duality
Astronomy
Practical Skills and Data Analysis
Topic overviewChoosing and using measuring instrumentsPrecision, accuracy and recording measurementsUsing the cathode ray oscilloscope to measure voltage and frequencyTables, graphs and presenting resultsLinearising a relationship and using the gradientAbsolute and percentage uncertaintyCombining uncertainties and uncertainty on a graphRandom and systematic error, reliability and refining an experiment
Deformation of Solids
Thermal Physics
Topic overviewBoyle's law, Charles's law and the pressure lawThe ideal gas equation pV = nRTThe Avogadro constant, the mole and pV = NkTInternal energy and the distribution of molecular energyThe kinetic theory equation pV = ⅓Nm⟨c²⟩Average molecular kinetic energy and temperatureAbsolute zero and the kelvin scaleSpecific heat capacity and the electrical method
Uniform Circular Motion
Simple Harmonic Motion
Topic overviewDefining simple harmonic motion and a = −ω²xDisplacement, velocity and acceleration: x = A cos ωtThe simple pendulum and T = 2π√(l/g)The loaded spiral spring and T = 2π√(m/k)SHM graphs and finding velocity from a gradientFree vibrations, forced vibrations and resonanceDamping: light, critical and over-damping
The Nucleus and Radioactive Decay
Topic overviewAlpha-particle scattering and the nuclear atomNuclear radius and nucleon numberThe density of nuclear matterAlpha, beta and gamma radiation: nature, penetration and rangeNuclear equations and changes in nucleon and proton numberThe random and exponential nature of radioactive decayActivity, the decay constant and A = −λNExponential decay calculations with A = A₀e^(−λt)Half-life and measuring it
Nuclear Energy, Fission and Fusion
Gravitational Fields
Electric Fields
Capacitors
Magnetic Fields
Charged Particles and Accelerators
Charged Particles and Accelerators
Relativistic mass increase
- 3 things to know
- Unit A2 2
Overview
Recall questions on what happens to mass as a particle approaches the speed of light, the equation with every symbol, why the effect is unnoticed at everyday speeds, worked factors at 0.99c and at 0.50c, why a particle with mass can never reach the speed of light, the consequences for accelerator design, and E = mc² with the electron rest energy.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Why is relativistic mass increase not noticed at everyday speeds?
Numbers
Calculate the factor by which the mass of a particle increases at 0.99c.
Questions from this subtopic
Each one with the model answer underneath.
- 1
What happens to the mass of a particle as it is accelerated towards the speed of light?
Model answer
Its mass increases above its rest mass, and the increase becomes very large as the speed approaches that of light.
- 2
Give the equation for relativistic mass and define each symbol.
Model answer
m = m₀/√(1 − v²/c²), where m is the mass at speed v, m₀ the rest mass, v the speed and c the speed of light.
- 3
What is the rest mass of a particle?
Model answer
Its mass measured in a frame in which it is at rest.
- 4
Why is the effect not noticed at everyday speeds?
Model answer
v²/c² is utterly negligible at ordinary speeds, so the square root is indistinguishable from one.
- 5
Calculate the factor by which the mass of a particle increases at 0.99c.
Model answer
1 − 0.99² is 0.0199, whose square root is 0.141, so the mass is 1 ÷ 0.141, which is 7.1 times the rest mass.
- 6
Calculate the mass increase factor at half the speed of light.
Model answer
1 − 0.25 is 0.75, whose square root is 0.866, so the mass is 1.15 times the rest mass.
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