GCSE Combined Science Physics key terms and definitions
13 Physics terms with their meanings, in alphabetical order. Each comes from a Yumio Physics lesson or the plain-words glossary, and links to the topic where it is taught.
Yumio is not affiliated with, endorsed by or connected to AQA, Pearson Edexcel or any other exam board.
- Acceleration
- How quickly the speed changes. It is the change in speed divided by the time taken.
- Current
- The flow of electric charge round a circuit, measured in amps.
- Density
- How much mass is packed into each unit of volume.
- Energy
- The ability to make things happen. It is measured in joules, and it is never used up, only moved or changed.
- Force
- A push or a pull. It is measured in newtons.
- Frequency
- How many waves pass a point each second, measured in hertz.
- Potential difference
- The push that moves charge round a circuit, measured in volts.
- Power
- How fast energy is transferred. It is energy divided by time, measured in watts.
- Pressure
- How much force is pressing on each unit of area.
- Resistance
- How hard it is for current to flow, measured in ohms. More resistance means less current.
- Speed
- How far something goes in each unit of time.
- Velocity
- Speed in a stated direction.
- Wavelength
- The distance from one point on a wave to the same point on the next wave.
Quantities, symbols and units
The quantities that appear in the physics equations, with the symbol used and the SI unit. Learn these pairs: a missing or wrong unit loses marks.
| Quantity | Symbol | Unit |
|---|---|---|
| Acceleration | a | m/s² |
| Area of the surface | A | m² |
| Change in momentum | Δp | kg m/s |
| Change in thermal energy | ΔE | J |
| Change in velocity | Δv | m/s |
| Charge flow | Q | C |
| Current | I | A |
| Density | ρ | kg/m³ |
| Density of the liquid | ρ | kg/m³ |
| Distance | s | m |
| Distance from the pivot | d | m |
| Distance moved along the line of action | s | m |
| Distance travelled | s | m |
| Efficiency (a fraction, or × 100 for a percentage) | efficiency | |
| Elastic potential energy | Eₑ | J |
| Energy transferred | E | J |
| Extension | e | m |
| Final velocity | v | m/s |
| Force | F | N |
| Force normal to the surface | F | N |
| Frequency | f | Hz |
| Gravitational field strength | g | N/kg |
| Gravitational potential energy | Eₚ | J |
| Height | h | m |
| Height of the column | h | m |
| Initial velocity | u | m/s |
| Kinetic energy | Eₖ | J |
| Length of conductor in the field | l | m |
| Magnetic flux density | B | T |
| Mass | m | kg |
| Moment | M | Nm |
| Momentum | p | kg m/s |
| Period | T | s |
| Potential difference | V | V |
| Power | P | W |
| Pressure | p | Pa |
| Pressure of the gas | p | Pa |
| Primary current | Iₚ | A |
| Primary potential difference | Vₚ | V |
| Resistance | R | Ω |
| Resultant force | F | N |
| Secondary current | Iₛ | A |
| Secondary potential difference | Vₛ | V |
| Specific heat capacity | c | J/kg°C |
| Specific latent heat | L | J/kg |
| Speed | v | m/s |
| Spring constant | k | N/m |
| Temperature change | Δθ | °C |
| Thermal energy for a change of state | E | J |
| Time | t | s |
| Time taken | t | s |
| Total input energy transfer | E(total) | J |
| Turns on the primary coil | nₚ | turns |
| Turns on the secondary coil | nₛ | turns |
| Useful output energy transfer | E(useful) | J |
| Velocity | v | m/s |
| Volume | V | m³ |
| Volume of the gas | V | m³ |
| Wave speed | v | m/s |
| Wavelength | λ | m |
| Weight | W | N |
| Work done | W | J |
See every equation and whether it is given or must be learned.
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