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IGCSE Physics syllabus map Cambridge IGCSE Physics 0625

Formula sheet

Every equation and relationship the 0625 syllabus asks you to recall and use, in syllabus order, with what each symbol means and its unit. Each equation links the Physiworld lesson that teaches it; lessons open with a free account. The revision notes explain each topic with worked examples.

Core every candidate Supplement Extended candidates only

No equation sheet in the exam. Cambridge does not print these in 0625 papers, so every row here has to be learned. Core candidates need the Core rows; Extended candidates need all of them.

Motion

Equation	What it says, symbols and units	Lesson
R = √(F₁² + F₂²) 1.1Supplement	The resultant of two forces (or velocities) at right angles, by Pythagoras; or find it with a scale drawing. R resultant, N or m/s F₁, F₂ the two vectors at right angles, N or m/s	Dynamics 9 · Forces at an Angle
v = st 1.2Core	Speed is the distance travelled each second. v speed, m/s s distance, m t time, s	Dynamics 5 · Distance–Time Graphs
average speed = total distance travelledtotal time taken 1.2Core	Use the whole journey, stops included.	Dynamics 5 · Distance–Time Graphs
distance = area under a speed–time graph 1.2Core	For constant speed or constant acceleration, the area under the line is the distance travelled.	Dynamics 5 · Velocity–Time Graphs
g ≈ 9.8 m/s² 1.2Core	Near the Earth's surface, an object in free fall accelerates at about 9.8 m/s² if air resistance is small. g acceleration of free fall, m/s²	Gravity 1 · Free Fall
a = ΔvΔt 1.2Supplement	Acceleration is the change in velocity each second; a deceleration is a negative acceleration. a acceleration, m/s² Δv change in velocity, m/s Δt time taken, s	Dynamics 5 · Velocity–Time Graphs

Mass, weight and density

Equation	What it says, symbols and units	Lesson
g = Wm 1.3Core	Gravitational field strength is the force on each kilogram, and it equals the acceleration of free fall. g gravitational field strength, N/kg W weight, N m mass, kg	Gravity 1 · Mass & Weight
W = mg 1.3Core	Weight is the gravitational force on a mass; on Earth g is about 9.8 N/kg. W weight, N m mass, kg g gravitational field strength, N/kg	Gravity 1 · Mass & Weight
ρ = mV 1.4Core	Density is the mass of each cubic metre of a material; a solid less dense than a liquid floats in it. ρ density, kg/m³ m mass, kg V volume, m³	Fluids 1 · Density

Forces and momentum

Equation	What it says, symbols and units	Lesson
resultant = sum of forces along a line 1.5.1Core	Forces in the same direction add; forces in opposite directions subtract.	Dynamics 4 · Resultant Force
k = Fx 1.5.1Supplement	The spring constant is the force for each metre of extension, up to the limit of proportionality. F force, N k spring constant, N/m x extension, m	Dynamics 6 · Hooke’s Law
F = ma 1.5.1Supplement	A resultant force accelerates a mass, in the direction of the force. F resultant force, N m mass, kg a acceleration, m/s²	Dynamics 1 · Newton’s Second Law
moment = F × d 1.5.2Core	The turning effect of a force grows with the force and with its perpendicular distance from the pivot. moment N m F force, N d perpendicular distance from the pivot, m	Dynamics 7 · Moments
sum of clockwise moments = sum of anticlockwise moments 1.5.2Core	Core: one force on each side of the pivot. Supplement: any number of forces. In equilibrium there is no resultant force and no resultant moment.	Dynamics 7 · The Principle of Moments
p = mv 1.6Supplement	Momentum is mass times velocity, and it has a direction. p momentum, kg m/s m mass, kg v velocity, m/s	Dynamics 2 · Momentum
impulse = FΔt = Δ(mv) 1.6Supplement	A force acting for a time changes the momentum by that amount. impulse N s F force, N Δt time the force acts, s Δ(mv) change in momentum, kg m/s	Dynamics 2 · Impulse
total momentum before = total momentum after 1.6Supplement	In a collision or explosion with no outside force, the total momentum does not change.	Dynamics 2 · Conservation of Momentum
F = ΔpΔt 1.6Supplement	Resultant force is the rate of change of momentum, so a longer impact time means a smaller force. F resultant force, N Δp change in momentum, kg m/s Δt time taken, s	Dynamics 2 · Impulse

Energy, work and power

Equation	What it says, symbols and units	Lesson
E_k = ½mv² 1.7.1Supplement	Energy of a moving object; double the speed and the kinetic energy is four times as big. E_k kinetic energy, J m mass, kg v speed, m/s	Dynamics 3 · Kinetic Energy
ΔE_p = mgΔh 1.7.1Supplement	Energy gained by a mass lifted through a height, near the Earth's surface. ΔE_p change in gravitational potential energy, J m mass, kg g gravitational field strength, N/kg Δh change in height, m	Dynamics 3 · Energy Conservation
W = Fd = ΔE 1.7.2Core	The work a force does is the energy it transfers. W work done, J F force, N d distance moved in the direction of the force, m ΔE energy transferred, J	Dynamics 3 · Work Done
efficiency = useful energy outputtotal energy input (× 100%) 1.7.3Supplement	The share of the input that ends up useful; the same with useful power output over total power input. Never more than 100%. efficiency a ratio or a percentage	Dynamics 3 · Power
P = Wt = ΔEt 1.7.4Core	Power is how fast work is done or energy is transferred; 1 W is 1 J each second. P power, W W work done, J ΔE energy transferred, J t time, s	Dynamics 3 · Power

Pressure

Equation	What it says, symbols and units	Lesson
p = FA 1.8Core	Pressure is force per unit area: the same force on a bigger area gives a smaller pressure. p pressure, Pa (N/m²) F force at right angles to the surface, N A area, m²	Fluids 3 · Pressure
Δp = ρgΔh 1.8Supplement	Pressure in a liquid rises with depth and with the liquid's density. Δp change in pressure, Pa ρ density of the liquid, kg/m³ g gravitational field strength, N/kg Δh change in depth, m	Fluids 3 · Pressure & Depth

Thermal physics

Equation	What it says, symbols and units	Lesson
T (in K) = θ (in °C) + 273 2.1.3Core	Absolute zero, −273 °C, is 0 K; a change of 1 °C is a change of 1 K. T temperature, K θ temperature, °C	Thermal 5 · Absolute Zero
pV = constant 2.1.3Supplement	For a fixed mass of gas at constant temperature, halve the volume and the pressure doubles (p₁V₁ = p₂V₂). p pressure, Pa V volume, m³	Thermal 8 · Squeeze a Gas
c = ΔEmΔθ 2.2.2Supplement	Specific heat capacity is the energy needed to raise 1 kg of a material by 1 °C. c specific heat capacity, J/(kg °C) ΔE energy transferred, J m mass, kg Δθ temperature change, °C	Thermal 1 · Specific Heat Capacity

Waves and light

Equation	What it says, symbols and units	Lesson
v = fλ 3.1Core	Wave speed is frequency times wavelength, for every kind of wave. v wave speed, m/s f frequency, Hz λ wavelength, m	Waves 1 · Wave Speed
angle of incidence = angle of reflection 3.2.1Core	Both angles are measured from the normal.	Optics 2 · Mirror law
n = speed of light in a vacuum (or air)speed of light in the material 3.2.2Supplement	Refractive index says how many times slower light travels in the material. n refractive index	Optics 1 · Slower in Glass
n = sin isin r 3.2.2Supplement	How strongly a material bends light entering it from air. n refractive index i angle of incidence, ° r angle of refraction, °	Optics 3 · Snell’s Law
n = 1sin c 3.2.2Supplement	Beyond the critical angle, light inside the material is totally internally reflected. n refractive index c critical angle, °	Optics 3 · Trapped Light
c = 3.0 × 10⁸ m/s 3.3Supplement	All electromagnetic waves travel at this speed in a vacuum, and at about the same speed in air. c speed of electromagnetic waves, m/s	Waves 6 · The EM Spectrum

Electricity

Equation	What it says, symbols and units	Lesson
I = Qt 4.2.2Supplement	Current is the charge passing a point each second. I current, A Q charge, C t time, s	Electricity 3 · Current
E = WQ 4.2.3Supplement	E.m.f. is the energy a source gives each coulomb of charge it moves round the circuit. E e.m.f., V W work done by the source, J Q charge, C	Electricity 3 · Potential Difference
V = WQ 4.2.3Supplement	Potential difference is the energy each coulomb transfers as it passes through a component. V potential difference, V W work done (energy transferred), J Q charge, C	Electricity 3 · Potential Difference
R = VI 4.2.4Core	Resistance is the potential difference needed for each ampere of current. R resistance, Ω V potential difference, V I current, A	Electricity 3 · Resistance
R ∝ l and R ∝ 1A 4.2.4Supplement	A longer metal wire has more resistance; a thicker one has less. R resistance, Ω l length, m A cross-sectional area, m²	Electricity 9 · A Wire’s Resistance
P = IV 4.2.5Core	Electrical power is current times potential difference. P power, W I current, A V potential difference, V	Electricity 5 · Power & Fuses
E = IVt 4.2.5Core	Energy an electric current transfers in a time t. E energy, J I current, A V potential difference, V t time, s	Electricity 10 · Paying for Energy
energy (kW h) = power (kW) × time (h) 4.2.5Core	The kilowatt-hour is the unit on an electricity bill: cost = energy in kW h × price per kW h.	Electricity 10 · Paying for Energy
R = R₁ + R₂ + … 4.3.2Core	Resistances in series add up; so do the e.m.f.s of cells in series. R combined resistance, Ω	Electricity 5 · Series
1R = 1R₁ + 1R₂ 4.3.2Supplement	Two resistors in parallel have less resistance than either one alone. R combined resistance, Ω	Electricity 5 · Parallel
current in = current out (junction); p.d.s add in series; parallel branches share one p.d. 4.3.2Supplement	The three rules for sharing current and potential difference in a circuit.	Electricity 5 · Parallel
R₁R₂ = V₁V₂ 4.3.3Supplement	A potential divider shares the supply p.d. in proportion to the two resistances. R₁, R₂ the two resistances, Ω V₁, V₂ the p.d. across each, V	Electricity 9 · Potential Dividers

Electromagnetism

Equation	What it says, symbols and units	Lesson
V_pV_s = N_pN_s 4.5.6Core	A transformer changes an alternating voltage in the ratio of its turns. V_p, V_s p.d. across primary and secondary coil, V N_p, N_s number of turns on each coil	Electricity 11 · Building the Grid
I_pV_p = I_sV_s 4.5.6Supplement	For a 100% efficient transformer, power in equals power out: step the voltage up and the current goes down. I_p, I_s current in primary and secondary coil, A V_p, V_s p.d. across each coil, V	Electricity 11 · Why Such High Voltage?
P = I²R 4.5.6Supplement	Power lost heating a resistance; a smaller current wastes much less, which is why the grid uses high voltage. P power, W I current, A R resistance, Ω	Electricity 11 · Why Such High Voltage?

Nuclear physics

Equation	What it says, symbols and units	Lesson
after n half-lives, fraction left = (½)ⁿ 5.2.4Core	Half-life is the time for half the undecayed nuclei of an isotope to decay. n number of half-lives	Nuclear 2 · Half-Life

Space physics

Equation	What it says, symbols and units	Lesson
v = 2πrT 6.1.1Supplement	Average orbital speed is the distance round the orbit divided by the time for one orbit. v average orbital speed, m/s r average radius of the orbit, m T orbital period, s	Gravity 8 · Moons and Machines
1 light-year = the distance light travels through space in one year 6.2.2Core	A unit of distance, not of time, used for the distances between stars and galaxies.	Space 1 · Light-Years
1 light-year ≈ 9.5 × 10¹⁵ m 6.2.2Supplement	The distance light travels through space in one year.	Space 1 · Light-Years
H₀ = vd 6.2.3Supplement	Further galaxies move away faster; current estimate H₀ ≈ 2.2 × 10⁻¹⁸ per second. H₀ Hubble constant, 1/s v speed the galaxy moves away, m/s d distance to the galaxy, m	Space 6 · Hubble’s Law
dv = 1H₀ 6.2.3Supplement	An estimate of the age of the Universe: run the expansion backwards to a single point.	Space 6 · Hubble’s Law

Written in Physiworld's own words from the 0625 syllabus for exams from 2026. Section numbers are the syllabus's.

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