Physics › Equations › To learn

A-level physics equations to memorise

These 34 equations are not printed in the AQA data booklet. They are grouped by unit; each link opens the equation, its conditions and the lesson in which it is derived.

34 equations · 15 units.

How many are actually yours

21 of them are core, and everybody sits those. The other 13 sit in the five option units, of which you take one: Electronics 4, Medical physics 4, Astrophysics 3, Engineering physics 1, Turning points 1. So the number you personally have to carry is 22 to 25. The option headings below say which is which.

What the booklet does print

Anything the booklet prints, you do not need to memorise. Every candidate sits every paper with the same booklet on the desk, options included: the constants, the algebra and geometry, the particle tables, and the standard results for waves, mechanics, materials, electricity, circular motion, simple harmonic motion, thermal physics, the fields, capacitors and nuclear decay. It prints the whole quark and lepton table, so those questions are about using it. The 34 below are what is left of the 214 equations the notes display once the booklet is accounted for.

The list

By unit, in the order the course runs.

MEASUREMENTS

• Percentage uncertaintyUncertainty and error

MECHANICS

• Weight from massMass and weight
• MomentumMomentum and impulse

WAVES

• Phase difference from path difference dProgressive waves
• Harmonic wavelengths on a string of length LStationary waves on strings
• Constructive interference conditionInterference and Young's double slit
• Destructive interference conditionInterference and Young's double slit
• Grating spacing from N lines per metreDiffraction gratings

PARTICLES

• Specific chargeConstituents of the atom

ELECTRICITY

• Electrical energy transferred in time tSeries, parallel and power
• Potential divider outputThe potential divider and its output

THERMAL PHYSICS

• Work done by a gas at constant pressureIdeal gases and the gas laws

GRAVITATIONAL FIELDS

• Orbit condition: gravity as the centripetal forceOrbits and satellites
• Kepler's third law, from NewtonOrbits and satellites
• Escape velocityOrbits and satellites

CAPACITANCE

• Halving time for a discharging capacitorThe time constant and exponential decay

MAGNETIC FIELDS

• Radius of a charge's circular path in a fieldForce on a moving charge

NUCLEAR PHYSICS

• Activity falling with timeRadioactive decay and the decay constant
• Closest approach: the alpha's kinetic energyNuclear radius and density
• Nuclear density from R₀Nuclear radius and density
• Neutron energy kept in an elastic moderator collisionNuclear reactors and safety

ELECTRONICS · OPTION

• Current in a zener regulator's series resistorZener diodes and semiconductor sensors
• Cut-off frequency of an RC filterBand-pass, band-stop and RC filters
• The gain-bandwidth equationNegative feedback amplifiers
• Frequency after n dividing stagesFlip-flops, counters and clocks

ENGINEERING PHYSICS · OPTION

• Acceleration along the arc at radius rRotational motion and the angular equations

ASTROPHYSICS · OPTION

• Collecting power and objective diameterResolving power, collecting power and the CCD
• Radiation flux from luminosity and distanceThe apparent magnitude scale
• Observed frequency from a source moving towards youThe Doppler effect and red shift

TURNING POINTS · OPTION

• Kinetic energy at a relativistic speedLength contraction, mass and energy

MEDICAL PHYSICS · OPTION

• Depth of a boundary from its echo timeUltrasound imaging
• Maximum photon energy from the tube voltageThe physics of diagnostic X-rays
• Intensity of a wave from its power and areaIntensity, loudness and the decibel scale
• Relative intensity level of two soundsIntensity, loudness and the decibel scale

Every equation the library displays, printed or not, is indexed on the equation index; if you know what an equation looks like but not what it is called, the search box holds all 214 of them by their own symbols. The flashcards drill this same list, under these same names.