Written by IGCSEPhysics Content Team · Physics subject adviser: K. S. Tan, 15+ years teaching IGCSE Physics · Checked against the Cambridge IGCSE Physics (0625) 2026 to 2028 syllabus
The IGCSE Physics exam provides an equation sheet. However, some equations are NOT on the sheet. You must memorise these.
Equations not on the sheet
Motion:
- Average speed = total distance / total time
Forces:
- Weight = mass x gravitational field strength (W = mg)
- Moment = force x perpendicular distance from pivot
Pressure:
- Pressure = force / area (p = F/A)
- Pressure in a liquid = height x density x gravitational field strength (p = h rho g)
Energy:
- Efficiency = useful energy output / total energy input (x 100%)
- Efficiency = useful power output / total power input (x 100%)
Waves:
- Wave speed = frequency x wavelength (v = f lambda)
Electricity:
- Charge = current x time (Q = It)
- Voltage = current x resistance (V = IR)
- Power = current x voltage (P = IV)
- Power = current^2 x resistance (P = I^2 R)
- Energy = power x time (E = Pt)
- Energy = current x voltage x time (E = IVt)
- Resistors in series: R_total = R1 + R2 + …
- Resistors in parallel: 1/R_total = 1/R1 + 1/R2 + …
Transformers (Extended):
- Vp/Vs = Np/Ns
- VpIp = VsIs (for an ideal transformer)
Equations given on the sheet
These are provided in the exam, so you do not need to memorise them, but you must know how to use them:
- s = d/t (speed)
- a = (v-u)/t (acceleration)
- F = ma (force)
- p = mv (momentum)
- Ek = 0.5 mv^2 (kinetic energy)
- Ep = mgh (gravitational potential energy)
- E = mc delta T (specific heat capacity)
- E = mL (specific latent heat)
What to do with this list
Write each equation on one side of a flashcard and its meaning on the other. Test yourself daily until you can write all of them from memory without hesitation.
Need Help Applying This?
A 0625 specialist can work through the student's current paper or question and help identify whether the main difficulty is content, mathematics, practical reasoning or exam technique.