Units in Science - GCSE Physics
Units in Science
Learners should understand the physical quantities and corresponding units used in GCSE Physics. The use of common symbols is optional, but learners should be able to use the quantities and units in qualitative work and calculations.
The units listed here include SI base units, SI derived units, and accepted units used in the specification.
SI base units
| Physical quantity | Common symbol(s) | SI unit / accepted unit | Unit abbreviation |
|---|---|---|---|
| Length | d: perpendicular distance from a pivot to the line of action of a force h: height or height raised above ground level l: length, for example of a wire s: displacement or distance travelled; displacement of a force along its line of action x: extension, for example of a spring lambda: wavelength | metre | m |
| Mass | m | kilogram | kg |
| Time | t | second | s |
| Temperature | T for kelvin temperature | kelvin | K |
| Current | I | ampere | A |
| Amount of substance | n | mole | mol |
SI derived and accepted units
| Physical quantity | Common symbol(s) | SI unit / accepted unit | Unit abbreviation |
|---|---|---|---|
| Area | A | squared metre | m2 |
| Volume | V | cubic metre; litre; cubic decimetre | m3; l; dm3 |
| Density | rho | kilogram per cubic metre | kg/m3 |
| Temperature | theta: Celsius temperature Delta theta: change in Celsius temperature | degree Celsius | degrees C |
| Pressure | p | pascal | Pa |
| Specific heat capacity | c | joule per kilogram per degree Celsius | J/kg degrees C |
| Specific latent heat | l | joule per kilogram | J/kg |
| Speed | v: final speed or velocity u: initial speed or velocity | metre per second | m/s |
| Force | F: forces generally W: weight or gravitational force | newton | N |
| Gravitational field strength | g | newton per kilogram | N/kg |
| Acceleration | a | metre per squared second | m/s2 |
| Frequency | f | hertz | Hz |
| Energy | E: energy transferred Delta E: change in thermal energy W: work done mechanically or electrically | joule | J |
| Power | P | watt | W |
| Electric charge | Q | coulomb | C |
| Electric potential difference | V | volt | V |
| Electric resistance | R | ohm | Ohm |
| Magnetic flux density | B | tesla | T |
| Moment | M | newton metre | Nm |
| Momentum | p | kilogram metre per second | kg m/s |
| Periodic time | T | second | s |
| Spring constant | k | newton per metre | N/m |
| Number of turns | Np: turns on primary coil Ns: turns on secondary coil | unitless | unitless |
| Efficiency | unitless | unitless |