Cambridge IGCSE Physics 0625 Syllabus Practice Flashcards

A set of vocabulary-style flashcards covering the key physical quantities, definitions, and formulas from the 2026-2028 Cambridge IGCSE Physics (0625) syllabus.

Speed

Defined as distance travelled per unit time; recall and use the equation $v = \frac{s}{t}$

Velocity

Defined as speed in a given direction

Acceleration

Defined as the change in velocity per unit time; recall and use the equation $a = \frac{\Delta v}{\Delta t}$

Mass

A measure of the quantity of matter in an object at rest relative to the observer

Weight

A gravitational force on an object that has mass

Gravitational field strength ($g$)

Defined as force per unit mass; recall and use the equation $g = \frac{W}{m}$. Near the surface of the Earth, it is approximately $9.8\,\text{N/kg}$

Density ($\rho$)

Defined as mass per unit volume; recall and use the equation $\rho = \frac{m}{V}$

Spring constant ($k$)

Defined as force per unit extension; recall and use the equation $k = \frac{F}{x}$

Limit of proportionality

The point on a load–extension graph beyond which the extension is no longer directly proportional to the load

Moment of a force

A measure of its turning effect; defined as $\text{force} \times \text{perpendicular distance from the pivot}$

Centre of gravity

The point through which the whole weight of an object acts

Momentum ($p$)

Defined as $\text{mass} \times \text{velocity}$; recall and use the equation $p = mv$

Impulse

Defined as $\text{force} \times \text{time}$ for which the force acts; recall and use the equation $\text{impulse} = F\Delta t = \Delta(mv)$.

Kinetic energy ($E_k$)

Recall and use the equation $E_k = \frac{1}{2}mv^2$

Gravitational potential energy ($\Delta E_p$)

Recall and use the equation for the change in energy $\Delta E_p = mg\Delta h$

Work ($W$)

Calculated using the equation for mechanical working $W = Fd = \Delta E$, where mechanical work done is equal to the energy transferred

Efficiency

The percentage of energy or power that is useful: $(\%)\,\text{efficiency} = \frac{\text{useful energy output}}{\text{total energy input}} \times 100\%$

Power ($P$)

Defined as work done per unit time or energy transferred per unit time; recall and use equations $P = \frac{W}{t}$ and $P = \frac{\Delta E}{t}$

Pressure ($p$)

Defined as force per unit area: $p = \frac{F}{A}$. For liquids, use $\Delta p = \rho g\Delta h$

Absolute zero

The lowest possible temperature ($-273^{\circ}\text{C}$) where the particles have the least kinetic energy

Specific heat capacity ($c$)

The energy required per unit mass per unit temperature increase; recall and use the equation $c = \frac{\Delta E}{m\Delta\theta}$

Transverse Wave

A wave where the direction of vibration is at right angles to the direction of propagation (e.g., electromagnetic radiation or water waves)

Longitudinal Wave

A wave where the direction of vibration is parallel to the direction of propagation (e.g., sound waves)

Refractive Index ($n$)

The ratio of the speeds of a wave in two different regions, or $n = \frac{\sin(i)}{\sin(r)}$

Critical Angle ($c$)

The angle of incidence in a denser medium for which the angle of refraction in the less dense medium is $90^{\circ}$. Related to the refractive index by $n = \frac{1}{\sin(c)}$

Monochromatic

Visible light consisting of a single frequency

Ultrasound

Sound with a frequency higher than $20\,\text{kHz}$

Electric current ($I$)

Charge passing a point per unit time: $I = \frac{Q}{t}$. Conventional current flows from positive to negative

Electromotive force (e.m.f.)

The electrical work done by a source in moving a unit charge around a complete circuit, measured in volts ($V$)

Potential difference (p.d.)

The work done by a unit charge passing through a component, measured in volts ($V$)

Resistance ($R$)

Recall and use the equation; $R = \frac{V}{I}$

Proton number ($Z$)

The number of protons in the nucleus of an atom (atomic number)

Nucleon number ($A$)

The total number of protons and neutrons in a nucleus (mass number)

Isotope

Atoms of the same element that have more than one nuclear form, differing in the number of neutrons they contain

Background radiation

Ionising radiation that is always present in the environment, from sources like radon gas, rocks, food, and cosmic rays

Half-life

The time taken for half the nuclei of a particular isotope in any sample to decay

Light-year

The distance travelled in space by light in one year; equal to $9.5 \times 10^{15}\,\text{m}$

Redshift

An increase in the observed wavelength of electromagnetic radiation emitted from receding stars and galaxies

Hubble constant ($H_0$)

The ratio of the speed at which a galaxy is moving away from the Earth to its distance from the Earth; currently estimated at $2.2 \times 10^{-18}\,\text{s}^{-1}$

Accuracy

A measurement result that is described as being close to the true value

Precision

How close the measured values of a quantity are to each other