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IGCSE Physics Formula Sheet (0625)
IGCSE Physics Formula Sheet
Cambridge IGCSE Physics (0625) | Key Equations by Topic
Based on official Cambridge syllabus 2026-2028
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Featured Equations
Across motion, forces, energy, waves & electricity#1v = d / t
Speed = distance / time
v = Speed (m/s)
d = Distance (m)
t = Time (s)
d = Distance (m)
t = Time (s)
#2W = m × g
Weight = mass × gravitational field strength
W = Weight (N)
m = Mass (kg)
g = 9.8 N/kg on Earth
m = Mass (kg)
g = 9.8 N/kg on Earth
#3F = m × a
Resultant force (Extended) = mass × acceleration (Newton's 2nd law)
F = Force (N)
m = Mass (kg)
a = Acceleration (m/s²)
m = Mass (kg)
a = Acceleration (m/s²)
#4KE = ½ × m × v²
Kinetic energy (Extended) = ½ × mass × speed²
KE = Kinetic energy (J)
m = Mass (kg)
v = Speed (m/s)
m = Mass (kg)
v = Speed (m/s)
#5ρ = m / V
Density = mass / volume
ρ = Density (kg/m³)
m = Mass (kg)
V = Volume (m³)
m = Mass (kg)
V = Volume (m³)
#6p = F / A
Pressure = force / area
p = Pressure (N/m² or N/cm²; Pa is Extended)
F = Force (N)
A = Area (m²)
F = Force (N)
A = Area (m²)
#7v = f × λ
Wave speed = frequency × wavelength
v = Wave speed (m/s)
f = Frequency (Hz)
λ = Wavelength (m)
f = Frequency (Hz)
λ = Wavelength (m)
#8V = I × R
Potential difference = current × resistance (Ohm's law)
V = pd (volts, V)
I = Current (A)
R = Resistance (Ω)
I = Current (A)
R = Resistance (Ω)
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1. Measurement & Motion
M = 10⁶, k = 10³, c = 10⁻², m = 10⁻³
Multipliers - mega, kilo, centi, milli
Extended also: G = 10⁹ (giga), μ = 10⁻⁶ (micro), n = 10⁻⁹ (nano)
Extended also: G = 10⁹ (giga), μ = 10⁻⁶ (micro), n = 10⁻⁹ (nano)
C = 2πr, A = πr²
Circle - circumference and area
Rectangle area = length × width
Triangle area = ½ × base × height
Block volume = length × width × height
Cylinder volume = πr² × height
Rectangle area = length × width
Triangle area = ½ × base × height
Block volume = length × width × height
Cylinder volume = πr² × height
Average = total / number measured
Measuring multiples - average for a small length or short time
Example: period = time for many complete swings / number of swings
Results count as equal if within ± 10%
Example: period = time for many complete swings / number of swings
Results count as equal if within ± 10%
Resultant² = a² + b²
Two vectors at right angles (Extended) - find the resultant by calculation or scale drawing
a, b = Two forces or two velocities only
a, b = Two forces or two velocities only
v = d / t
Speed = distance / time
v = Speed (m/s)
d = Distance (m)
t = Time (s)
Tip: "How far per second?"
v = Speed (m/s)
d = Distance (m)
t = Time (s)
Tip: "How far per second?"
Average speed = total d / total t
Average speed = total distance / total time
Use the whole journey: total distance (m), total time (s)
Use the whole journey: total distance (m), total time (s)
a = Δv / Δt
Acceleration (Extended) = change in velocity / time
a = Acceleration (m/s²)
Δv = Change in velocity, final - initial (m/s)
Δt = Time taken (s)
Deceleration = negative acceleration
a = Acceleration (m/s²)
Δv = Change in velocity, final - initial (m/s)
Δt = Time taken (s)
Deceleration = negative acceleration
Speed = gradient
Distance-time graph - gradient of a straight section = speed
Read d and t from the straight section
Read d and t from the straight section
Distance = area under line
Speed-time graph - area under the line = distance travelled
For constant speed or constant acceleration
For constant speed or constant acceleration
Acceleration = gradient
Speed-time graph (Extended) - gradient = acceleration
Read Δv and Δt from the line
Read Δv and Δt from the line
2. Mass, Weight & Density
W = m × g
Weight = mass × gravitational field strength
W = Weight (Newtons)
m = Mass (kg)
g = Gravitational field strength (9.8 N/kg on Earth)
Same as acceleration of free fall (about 9.8 m/s²)
W = Weight (Newtons)
m = Mass (kg)
g = Gravitational field strength (9.8 N/kg on Earth)
Same as acceleration of free fall (about 9.8 m/s²)
ρ = m / V
Density = mass / volume
ρ (rho) = Density (kg/m³ or g/cm³)
m = Mass (kg)
V = Volume (m³)
An object floats if less dense than the liquid
Extended also: a liquid floats on a denser liquid if they do not mix
ρ (rho) = Density (kg/m³ or g/cm³)
m = Mass (kg)
V = Volume (m³)
An object floats if less dense than the liquid
Extended also: a liquid floats on a denser liquid if they do not mix
3. Forces
Resultant = add or subtract
Resultant force - same direction: add; opposite directions: subtract
Two or more forces along one straight line
Two or more forces along one straight line
F = m × a
Force (Extended) = mass × acceleration (Newton's 2nd Law)
F = Force (Newtons)
m = Mass (kg)
a = Acceleration (m/s²)
F = Force (Newtons)
m = Mass (kg)
a = Acceleration (m/s²)
k = F / x
Spring constant (Extended) = force / extension (Hooke's Law)
k = Spring constant (N/m)
F = Force (Newtons)
x = Extension (metres)
k = Spring constant (N/m)
F = Force (Newtons)
x = Extension (metres)
Moment = F × d
Moment = force × perpendicular distance from pivot
Moment in Newton-metres (Nm)
F = Force (Newtons)
d = Perpendicular distance from pivot (metres)
Moment in Newton-metres (Nm)
F = Force (Newtons)
d = Perpendicular distance from pivot (metres)
Clockwise moment = anticlockwise moment
Principle of moments - no resultant moment when balanced
One force each side of the pivot (Core)
More forces each side: add the moments on each side (Extended)
One force each side of the pivot (Core)
More forces each side: add the moments on each side (Extended)
4. Momentum (Extended)
p = m × v
Momentum = mass × velocity
p = Momentum (kg m/s)
m = Mass (kg)
v = Velocity (m/s)
p = Momentum (kg m/s)
m = Mass (kg)
v = Velocity (m/s)
Δp = mv - mu
Change in momentum = final momentum - initial momentum
Δp = Change in momentum (kg m/s)
v = Final velocity (m/s)
u = Initial velocity (m/s)
Δp = Change in momentum (kg m/s)
v = Final velocity (m/s)
u = Initial velocity (m/s)
F = Δp / Δt
Resultant force = change in momentum / time
F = Resultant force (Newtons)
Δp = Change in momentum (kg m/s)
Δt = Time taken (seconds)
F = Resultant force (Newtons)
Δp = Change in momentum (kg m/s)
Δt = Time taken (seconds)
Impulse = F × Δt
Impulse = force × time = change in momentum
Impulse (Newton-seconds, Ns or kg m/s)
F = Force (Newtons)
Δt = Time interval (s)
Impulse (Newton-seconds, Ns or kg m/s)
F = Force (Newtons)
Δt = Time interval (s)
Total p before = total p after
Conservation of momentum - total momentum stays the same
p = Momentum (kg m/s)
Use for simple problems in one dimension
p = Momentum (kg m/s)
Use for simple problems in one dimension
5. Energy, Work & Power
Eₖ = ½mv²
Kinetic energy (Extended) = ½ × mass × velocity²
Eₖ = Kinetic Energy (Joules)
m = Mass (kg)
v = Velocity (m/s)
Eₖ = Kinetic Energy (Joules)
m = Mass (kg)
v = Velocity (m/s)
ΔEₚ = m × g × Δh
Change in gravitational PE (Extended) = mass × g × change in height
ΔEₚ = Change in potential energy (J)
m = Mass (kg)
g = 9.8 N/kg
Δh = Change in height (m)
ΔEₚ = Change in potential energy (J)
m = Mass (kg)
g = 9.8 N/kg
Δh = Change in height (m)
Total energy before = total energy after
Conservation of energy - total energy stays the same
Simple examples and flow diagrams (Core)
Multi-stage examples and Sankey diagrams (Extended)
Simple examples and flow diagrams (Core)
Multi-stage examples and Sankey diagrams (Extended)
W = F × d = ΔE
Work done = force × distance moved = energy transferred
W = Work (Joules)
F = Force (Newtons)
d = Distance (metres)
ΔE = Energy transferred (Joules)
W = Work (Joules)
F = Force (Newtons)
d = Distance (metres)
ΔE = Energy transferred (Joules)
P = W / t = ΔE / t
Power = work done / time = energy transferred / time
P = Power (Watts)
W = Work (Joules)
ΔE = Energy transferred (Joules)
t = Time (seconds)
P = Power (Watts)
W = Work (Joules)
ΔE = Energy transferred (Joules)
t = Time (seconds)
Efficiency = useful out / total in × 100%
Efficiency (Extended) = useful output / total input × 100%
Efficiency in %, works for energy (J) or power (W)
Efficiency in %, works for energy (J) or power (W)
6. Pressure
p = F / A
Pressure = force / area
p = Pressure (N/m² or N/cm²; Pascals, Pa, is Extended)
F = Force (Newtons)
A = Area (m²)
p = Pressure (N/m² or N/cm²; Pascals, Pa, is Extended)
F = Force (Newtons)
A = Area (m²)
Δp = ρ × g × Δh
Change in pressure in a liquid (Extended) = density × g × change in depth
Δp = Pressure change (Pa)
ρ = Density (kg/m³)
g = 9.8 N/kg
Δh = Change in depth (metres)
Δp = Pressure change (Pa)
ρ = Density (kg/m³)
g = 9.8 N/kg
Δh = Change in depth (metres)
7. Thermal Physics
T (K) = θ (°C) + 273
Temperature conversion - Celsius to Kelvin
T = Absolute temperature (Kelvin)
θ (theta) = Temperature (°Celsius)
Absolute zero = -273 °C (0 K)
T = Absolute temperature (Kelvin)
θ (theta) = Temperature (°Celsius)
Absolute zero = -273 °C (0 K)
pV = constant
Boyle's Law (Extended) - pressure × volume = constant (fixed mass of gas, constant temperature)
p = Pressure (Pascals)
V = Volume (m³ or cm³)
p = Pressure (Pascals)
V = Volume (m³ or cm³)
ΔE = m × c × Δθ
Specific heat capacity (Extended) - energy = mass × SHC × temp change
ΔE = Energy (Joules)
m = Mass (kg)
c = Specific heat capacity in J/(kg °C)
Δθ = Temp change (°C)
ΔE = Energy (Joules)
m = Mass (kg)
c = Specific heat capacity in J/(kg °C)
Δθ = Temp change (°C)
Water: melts at 0 °C, boils at 100 °C
Melting and boiling of water - at standard atmospheric pressure
Temperature stays constant while melting or boiling
Temperature stays constant while melting or boiling
8. Waves, Light & Sound
v = f × λ
Wave equation - speed = frequency × wavelength
v = Wave speed (m/s)
f = Frequency (Hertz, Hz)
λ (lambda) = Wavelength (metres)
v = Wave speed (m/s)
f = Frequency (Hertz, Hz)
λ (lambda) = Wavelength (metres)
i = r
Law of reflection - angle of incidence = angle of reflection
i = Angle of incidence (degrees)
r = Angle of reflection (degrees)
Both measured from normal
i = Angle of incidence (degrees)
r = Angle of reflection (degrees)
Both measured from normal
n = v₁ / v₂
Refractive index (Extended) = ratio of wave speeds in two regions
n = Refractive index (no unit)
v₁ = Speed in air (m/s)
v₂ = Speed in the material (m/s)
n = Refractive index (no unit)
v₁ = Speed in air (m/s)
v₂ = Speed in the material (m/s)
n = sin i / sin r
Refractive index (Extended) (Snell's Law) - n = sin(incidence) / sin(refraction)
n = Refractive index (no unit)
i = Angle of incidence in air
r = Angle of refraction in the material
n = Refractive index (no unit)
i = Angle of incidence in air
r = Angle of refraction in the material
n = 1 / sin c
Critical angle (Extended) - equation for total internal reflection; Core needs only the meaning of the term
n = Refractive index, c = Critical angle (degrees) - angle of incidence, inside the material, at which the angle of refraction is 90°
n = Refractive index, c = Critical angle (degrees) - angle of incidence, inside the material, at which the angle of refraction is 90°
Speed of light = 3.0 × 10⁸ m/s
Electromagnetic waves (Extended) - speed in a vacuum, about the same in air
Core needs only: all travel at the same high speed in a vacuum
Core needs only: all travel at the same high speed in a vacuum
Speed of sound = 330-350 m/s
Sound - approximate speed in air
Extended also: usually faster in solids than liquids, and in liquids than gases
Extended also: usually faster in solids than liquids, and in liquids than gases
Human hearing = 20 Hz to 20 000 Hz
Audible range - approximate
Ultrasound = above 20 kHz
Ultrasound = above 20 kHz
Distance = speed × time
Ultrasound depth or distance (Extended) - from wave speed and time
A pulse travels there and back, so halve the echo time
A pulse travels there and back, so halve the echo time
9. Electricity
I = Q / t
Current (Extended) = charge / time
I = Current (Amperes)
Q = Charge (Coulombs)
t = Time (seconds)
I = Current (Amperes)
Q = Charge (Coulombs)
t = Time (seconds)
V = W / Q
Potential difference (p.d.) (Extended) = work done / charge
V = p.d. (Volts)
W = Work done (Joules)
Q = Charge (Coulombs)
Core needs only the definition, not this equation
V = p.d. (Volts)
W = Work done (Joules)
Q = Charge (Coulombs)
Core needs only the definition, not this equation
E = W / Q
Electromotive force (e.m.f.) (Extended) = work done / charge
E = e.m.f. (Volts)
W = Work done (Joules)
Q = Charge (Coulombs)
Core needs only the definition, not this equation
E = e.m.f. (Volts)
W = Work done (Joules)
Q = Charge (Coulombs)
Core needs only the definition, not this equation
V = I × R
Ohm's Law - voltage = current × resistance
V = Voltage (Volts)
I = Current (Amperes)
R = Resistance (Ohms, Ω)
V = Voltage (Volts)
I = Current (Amperes)
R = Resistance (Ohms, Ω)
P = I × V
Electrical power = current × voltage
P = Power (Watts)
I = Current (Amperes)
V = Voltage (Volts)
Fuse: find I = P / V, then choose the next rating above
P = Power (Watts)
I = Current (Amperes)
V = Voltage (Volts)
Fuse: find I = P / V, then choose the next rating above
E = P × t
Electrical energy = power × time (or E = I×V×t)
E = Energy (Joules)
P = Power (Watts)
t = Time (seconds)
E = Energy (Joules)
P = Power (Watts)
t = Time (seconds)
E (kW h) = P (kW) × t (h)
Kilowatt-hour (kW h) - energy used by 1 kW in 1 hour
Cost = energy used (kW h) × price per kW h
Cost = energy used (kW h) × price per kW h
P = I² × R
Power loss in cables (why high voltage = less loss) (Extended)
P = Power (Watts)
I = Current (Amperes)
R = Resistance (Ohms)
P = Power (Watts)
I = Current (Amperes)
R = Resistance (Ohms)
10. Resistance & Circuits
E = E₁ + E₂ + ...
Combined e.m.f. - sources in series: add the e.m.f.s
E = e.m.f. (Volts)
E = e.m.f. (Volts)
Rₜ = R₁ + R₂ + ...
Series resistance - total = sum of all resistances
R = Resistance (Ohms, Ω)
In series: same current flows through all
R = Resistance (Ohms, Ω)
In series: same current flows through all
R ∝ L
Resistance ∝ length (Extended) - Core needs only: longer wire = more resistance
R = Resistance (Ω)
L = Length (m)
Double length = double resistance
R = Resistance (Ω)
L = Length (m)
Double length = double resistance
R ∝ 1/A
Resistance ∝ 1/area (Extended) - Core needs only: thicker wire = less resistance
R = Resistance (Ω)
A = Cross-sectional area (m²)
Double area = half resistance
R = Resistance (Ω)
A = Cross-sectional area (m²)
Double area = half resistance
Total I in = total I out
Currents at a junction (Extended) - sum in = sum out
I = Current (Amperes)
I = Current (Amperes)
V = V₁ + V₂ + ...
Series p.d.s (Extended) - total p.d. = sum of p.d.s across components
V = p.d. (Volts)
V = p.d. (Volts)
1/Rₜ = 1/R₁ + 1/R₂
Parallel resistance (Extended) - reciprocal sum of resistances
R = Resistance (Ohms, Ω)
In parallel: same voltage across all
R = Resistance (Ohms, Ω)
In parallel: same voltage across all
R₁ / R₂ = V₁ / V₂
Potential divider (Extended) - ratio of resistances = ratio of voltages
R₁, R₂ = The two resistors (Ohms, Ω)
V₁, V₂ = Voltage across each resistor (Volts)
R₁, R₂ = The two resistors (Ohms, Ω)
V₁, V₂ = Voltage across each resistor (Volts)
11. Transformers
Vₚ/Vₛ = Nₚ/Nₛ
Transformer equation - voltage ratio = turns ratio
V = Voltage (Volts)
N = Number of turns
p = primary coil, s = secondary coil
V = Voltage (Volts)
N = Number of turns
p = primary coil, s = secondary coil
IₚVₚ = IₛVₛ
Transformer power (Extended) - power in = power out (100% efficiency)
I = Current (Amperes)
V = Voltage (Volts)
Power = I × V (Watts)
I = Current (Amperes)
V = Voltage (Volts)
Power = I × V (Watts)
12. Nuclear Physics
Proton +1, neutron 0, electron -1
Relative charges - of the particles in an atom
Protons and neutrons are in the nucleus; electrons orbit it
Protons and neutrons are in the nucleus; electrons orbit it
Neutrons = A - Z
Number of neutrons = nucleon number - proton number
A = Nucleon number (mass number)
Z = Proton number (atomic number)
A = Nucleon number (mass number)
Z = Proton number (atomic number)
AZX
Nuclide notation - A at the top, Z at the bottom, X = element symbol
Extended also: Z sets the relative charge of the nucleus, A its relative mass
Extended also: Z sets the relative charge of the nucleus, A its relative mass
Corrected = measured - background
Corrected count rate (Extended) = measured count rate - background count rate
Core needs only: count rates in counts/s or counts/min
Core needs only: count rates in counts/s or counts/min
Neutron → proton + electron
Beta emission (Extended) - change in the nucleus
Core needs only: in α-decay or β-decay the nucleus becomes a different element
Core needs only: in α-decay or β-decay the nucleus becomes a different element
α: A - 4, Z - 2
Decay equations (Extended) - effect on A and Z
β: A unchanged, Z + 1
γ: A and Z unchanged
β: A unchanged, Z + 1
γ: A and Z unchanged
Half-life
Half-life = time for half of the nuclei of an isotope in a sample to decay
Measured in s, min, h, days, weeks or years
After each half-life, half of the remaining nuclei have decayed
Measured in s, min, h, days, weeks or years
After each half-life, half of the remaining nuclei have decayed
13. Space Physics
Earth: 24 hours, 365 days
Earth and Moon - approximate times
Earth rotates once in about 24 hours
Earth orbits the Sun in about 365 days
Moon orbits the Earth in about one month
Earth rotates once in about 24 hours
Earth orbits the Sun in about 365 days
Moon orbits the Earth in about one month
v = 2πr / T
Average orbital speed (Extended) = circumference / orbital period
v = Average orbital speed (m/s)
r = Average orbital radius (metres)
T = Orbital period (seconds)
v = Average orbital speed (m/s)
r = Average orbital radius (metres)
T = Orbital period (seconds)
Time = distance / speed of light
Light travel time - for long distances such as across the Solar System
Time (s), distance (m), speed of light (m/s)
Time (s), distance (m), speed of light (m/s)
1 light-year = 9.5 × 10¹⁵ m
Light-year (Extended) - value in metres
Core needs only: distance light travels through space in one year
Core needs only: distance light travels through space in one year
Milky Way ≈ 100 000 light-years
Milky Way - approximate diameter
One of many billions of galaxies
One of many billions of galaxies
H₀ = v / d
Hubble's Law (Extended) - Hubble constant = recession speed / distance
v = Recession speed (m/s)
H₀ = Hubble constant (≈2.2×10⁻¹⁸ s⁻¹)
d = Distance (metres)
v = Recession speed (m/s)
H₀ = Hubble constant (≈2.2×10⁻¹⁸ s⁻¹)
d = Distance (metres)
d / v = 1 / H₀
Age of the Universe (Extended) - estimate from the Hubble constant
d = Distance of a far galaxy (metres)
v = Speed it is moving away (m/s)
H₀ = Hubble constant (s⁻¹)
d = Distance of a far galaxy (metres)
v = Speed it is moving away (m/s)
H₀ = Hubble constant (s⁻¹)
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LumiExams.com | Cambridge IGCSE Physics (0625) | Syllabus 2026-2028
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Frequently Asked Questions
What formulas do I need to memorize for IGCSE Physics?
IGCSE Physics (0625) uses key formulas covering motion (v=d/t, and a=Δv/Δt for Extended), forces (W=mg, and F=ma for Extended), energy (KE=½mv² and GPE=mgh, both Extended), electricity (V=IR, P=IV), waves (v=fλ), and more. No formula sheet is given in the exam, so you need to learn them.
Are formulas provided in the IGCSE Physics exam?
No. Cambridge does not provide a formula sheet for IGCSE Physics. The syllabus asks you to recall and use the equations. Papers 1 to 4 state g = 9.8 m/s² on the front page. Other data is given in the question, except values the syllabus expects you to know, such as the speed of sound in air. So learn the key equations, such as v=d/t, F=ma (Extended), V=IR and the energy formulas (KE and GPE are Extended). Our formula sheet groups them by topic.
How do I use this IGCSE Physics formula sheet?
1) Subscribe with your email to unlock the formula sheet. 2) Click 'Download as PDF' or use Ctrl+P to print. 3) Use the color-coded sections to find formulas by topic. 4) Practice with our worked examples page for step-by-step solutions.
What topics are covered in this Physics formula sheet?
The formula sheet groups key equations into 13 sections: Measurement & Motion, Mass/Weight/Density, Forces, Momentum, Energy/Work/Power, Pressure, Thermal Physics, Waves, Light & Sound, Electricity, Resistance & Circuits, Transformers, Nuclear Physics, and Space Physics.
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