Numbers
OCR A-Level Physics A H556
Practical Skills in the Written Papers
The Practical Endorsement
Topic overviewAnalogue and digital measuring instrumentsImproving accuracy with repeat timing, fiducial markers and plumb linesTiming, calipers and micrometersConstructing and testing circuitsSignal generators and oscilloscopesGenerating and measuring wavesData loggers, modelling software and ionising radiation
Physical Quantities and Units
Making Measurements and Analysing Data
Nature of Quantities
Motion
Forces in Action
Work, Energy and Power
Materials
Newton’s Laws of Motion and Momentum
Charge and Current
Energy, Power and Resistance
Electrical Circuits
Waves
Topic overviewProgressive waves and their propertiesThe wave equationReflection, refraction and diffractionWave graphs and intensityThe electromagnetic spectrumPolarisationRefraction and refractive indexCritical angle and total internal reflectionThe principle of superpositionInterference, coherence and path differenceTwo-source interference, Young's double-slit experiment and the diffraction gratingForming stationary wavesStationary waves on strings and in air columnsMeasuring the speed of soundNode spacing, amplitude and phase in stationary wavesHarmonics and the fundamental mode
Quantum Physics
Thermal Physics
Topic overviewThermal equilibrium and absolute temperatureThe kinetic model of solids, liquids and gasesBrownian motion and internal energySpecific heat capacityMeasuring specific heat capacitySpecific latent heatMeasuring specific latent heatMoles, the Avogadro constant and kinetic theoryGas laws, the ideal gas equation and r.m.s. speedMaxwell-Boltzmann distribution, Boltzmann constant and internal energy
Oscillations
Gravitational Fields
Astrophysics and Cosmology
Topic overviewThe solar system and the birth of a starThe death of a low-mass starSupernovae, neutron stars and black holesThe Hertzsprung-Russell diagramEnergy levels and emission spectraAbsorption spectra and spectral linesPhoton energy and the diffraction gratingWien's law and Stefan's lawAstronomical distances, parallax and the cosmological principleDoppler shift and Hubble's lawThe expanding universe and the Big BangEvidence for the Big Bang and dark energy
Capacitors
Topic overviewCapacitance and charging a capacitorCapacitors in seriesCapacitors in parallel and combined circuitsEnergy stored by a capacitorCharging and discharging through a resistorInvestigating capacitor dischargeThe time constantIterative modelling, exponential decay and the constant-ratio property
Electric Fields
Electromagnetism
Nuclear and Particle Physics
Topic overviewAlpha-particle scattering and the nuclear modelProton number, nucleon number and isotopesThe strong nuclear force and nuclear radiusParticles, antiparticles and hadronsLeptons and the quark modelQuark composition and chargesBeta decay in the quark modelRadioactive decay and the three radiationsNuclear decay equationsActivity, decay constant and half-lifeExponential decay and radioactive datingMass-energy equivalenceAnnihilation, mass defect and binding energyBinding energy per nucleon and induced fissionThe fission reactor and nuclear wasteNuclear fusion and balancing nuclear equations
Electrical Circuits
Potential dividers
- 2 things to know
- Papers 2 and 3
Overview
Recall questions on potential dividers and potentiometers, the potential divider equation and calculations, sensing circuits with LDRs and thermistors, and investigating how output voltage varies with light or temperature.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Process
How does the resistance of a light-dependent resistor (LDR) change with light intensity?
Questions from this subtopic
Each one with the model answer underneath.
- 1
Calculate the output voltage when input voltage = 11.5 V, first resistance = 4000 Ω, second resistance = 3600 Ω.
Model answer
Output voltage = (3600 ÷ (4000 + 3600)) × 11.5 = 5.45 V.
- 2
What is a potential divider?
Model answer
A circuit that uses resistors in series to produce an output voltage that is a fraction of the input voltage.
- 3
What is a potentiometer?
Model answer
A three-terminal variable resistor that can be used as a continuously adjustable potential divider.
- 4
State the potential divider equation for the output voltage across the second resistor.
Model answer
Vₒᵤₜ = (R₂ / (R₁ + R₂)) × Vᵢₙ
- 5
In a two-resistor potential divider, what is the relationship between the ratio of potential differences and the ratio of resistances?
Model answer
V₁/V₂ = R₁/R₂
- 6
How does the resistance of a light-dependent resistor (LDR) change with light intensity?
Model answer
The resistance decreases as the light intensity incident upon it increases.
Other ways to work this
The same content, four other ways.
What is inside Levo
Six ways to work the same material.
Every question in Electrical Circuits, 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.
Or £46 a year, about £3.83 a month. Cancel anytime.