CIE IGCSE Physics Formula Sheet

Average speed

Distance (m) / time (s); formula: s = d/t.

Average velocity

Displacement (m) / by time (s); formula: v = x/t.

Acceleration

Change in velocity (final - initial) / by time; formula: a = (v - u)/t.

Weight

Mass (kg) x gravitational field strength (ms−2); formula: W = mg.

Force

Mass (kg) x acceleration (ms−2); formula: F = ma.

Density

Mass (kg) / volume (m³); formula: ρ = m/V.

Hooke’s law

Force (N) is proportional to extension (m); formula: F = kx.

Pressure

Force (N) / area (m²); formula: P = F/A.

Fluide pressure (Pa)

density x gravitational field strength x height formula: P = ρgh.

Work

Force (N) x distance moved (m); formula: W = Fd.

Power (work)

Work (J) / time (s); formula: P = W/t.

Kinetic Energy

Half the mass (kg) x velocity squared (ms−1); formula: KE = 1/2 mv².

Gravitational potential energy

Mass (kg) x gravitational field strength (ms−2) and height (m); formula: GPE = mgh.

Efficiency

Useful power output / total power input x 100%; formula: η = Pout/Pin × 100%.

Moment (Nm)

Force (N) x perpendicular distance from pivot; formula M = Fd

sum of clockwise moments (Nm)

sum of anticlockwise moments (Nm); formula F1d1 = F2d2

Momentum (kgms^-1)

Mass (kg) x velocity (ms−1); formula: p = mv.

Impulsive Force (N)

change in momentum (kgms^-1) / time (s); Formula F = change in p / t

Impulse

Change in momentum (kgms−1); formula: Δp = mv - mu.

Boyle’s Law

Pressure1 (Pa) x Volume1 (m³) = Pressure2 (Pa) x Volume2 (m³); formula: P1V1 = P2V2.

Specific heat capacity

Energy (J) is mass (kg) x specific heat capacity (Jkg⁻¹°C⁻¹) times temperature change (°C); formula: Q = mcθ.

Temperature in celsius (C)

temperature in kelvin - 273.15; formula C = K - 273.15

Wave speed

Frequency (Hz) x wavelength (m); formula: V = fλ.

Frequency (Hz)

1 / period (s); formula 1/T

Refractive index (angles)

Ratio of the sine of the angle of incidence to the sine of the angle of refraction; formula: n = sin i/sin r.

Refractive Index (speed)

speed of light in vacuum / speed of light in material; formula n = c/v

Refractive index (critical angle)

1 / sine of critical angle; formula n= 1/sinc

Current

Charge (C) / time (s); formula: I = Q/t.

Voltage (charge)

Energy transferred (J) / charge (C); formula: V = W/Q.

Voltage (V)

current (A) x resistance (Ω); formula: V = IR

Power (electricity)

Current (A) x voltage (V); formula: P = IV.

Power Loss (W)

current² (A) x resistance (Ω); formula P = I²R

energy transferred (J) current

current (A) x voltage (V) x time (s); formula W = IVt

Energy transferred (J) power

power (W) x time (s); formula W = Pt

resistors in series; total resistance

sum of individual resistors

resistors in parallel

1/total resistance = 1/sum of individual resistors

resistance with wires

resistivity (ohm m) x length (m) / area (m²); formula R = pl / A

Transformers voltage and coil ratio

Ratio of voltage in secondary coil to voltage in primary coil equals ratio of turns on secondary to turns on primary; formula: Vs/Vp = Ns/Np.

transformers voltage and current ratio

voltage in secondary coil/voltage in primary coil = current in primary coil / current in secondary coil; formula Vs/Vp = Ip/Is

Alpha decay

Nuclear reaction where an atom emits an alpha particle; formula: ZX_A → Z-2Y + A-4He.

Beta decay

Nuclear reaction where an atom emits a beta particle; formula: ZX_A → Z+1Y_A + -1e_0.

Gamma Decay

average orbital speed (ms^-1)

2 x pi x average radius of the orbit (m) / orbital period (s); formula v = 2 pi r/T

Hubble's Law/ Hubble Constant

Distance of a far galaxy / speed away from us = 1/Hubble constant; formula: d/v = 1/H₀.
Hubble constant 2.2 × 10^-18 s^-1

speed of light

3.0 × 10⁸ m/s

1 light year

9.5 x 10^15 km