9702 Physics Formula Sheet & 9618 Paper 2 Pseudocode

9702 · 2025–2027

Physics data & formulae

The constants and formulae printed in Papers 1, 2 and 4, grouped for quick lookup.

Physical constants

Quantity	Symbol & value
Acceleration of free fall	g = 9.81 m s⁻²
Speed of light	c = 3.00 × 10⁸ m s⁻¹
Elementary charge	e = 1.60 × 10⁻¹⁹ C
Unified atomic mass unit	1 u = 1.66 × 10⁻²⁷ kg
Proton rest mass	m_p = 1.67 × 10⁻²⁷ kg
Electron rest mass	m_e = 9.11 × 10⁻³¹ kg
Avogadro constant	N_A = 6.02 × 10²³ mol⁻¹
Molar gas constant	R = 8.31 J K⁻¹ mol⁻¹
Boltzmann constant	k = 1.38 × 10⁻²³ J K⁻¹
Gravitational constant	G = 6.67 × 10⁻¹¹ N m² kg⁻²
Permittivity of free space	ε₀ = 8.85 × 10⁻¹² F m⁻¹
Coulomb constant	1/(4πε₀) = 8.99 × 10⁹ m F⁻¹
Planck constant	h = 6.63 × 10⁻³⁴ J s
Stefan–Boltzmann constant	σ = 5.67 × 10⁻⁸ W m⁻² K⁻⁴

AS formulae · Papers 1 & 2

Uniform accelerations = ut + ½at²

Uniform accelerationv² = u² + 2as

Hydrostatic pressureΔp = ρgΔh

UpthrustF = ρgV

Doppler effectfₒ = fₛv/(v ± vₛ)

Electric currentI = Anvq

Series resistorsR = R₁ + R₂ + …

Parallel resistors1/R = 1/R₁ + 1/R₂ + …

A Level formulae · Paper 4

Gravitational potentialφ = −GM/r

Gravitational P.E.Eₚ = −GMm/r

Ideal gas pressurep = ⅓(Nm/V)⟨c²⟩

Simple harmonic motiona = −ω²x

SHM velocityv = v₀ cos ωt

SHM velocityv = ±ω√(x₀² − x²)

Electric potentialV = Q/(4πε₀r)

Electrical P.E.Eₚ = Qq/(4πε₀r)

Series capacitors1/C = 1/C₁ + 1/C₂ + …

Parallel capacitorsC = C₁ + C₂ + …

Capacitor dischargex = x₀e^(−t/RC)

Hall voltageV_H = BI/(ntq)

Alternating currentx = x₀ sin ωt

Radioactive decayx = x₀e^(−λt)

Decay constantλ = 0.693/t_½

Stefan–Boltzmann lawL = 4πσr²T⁴

Doppler redshiftΔλ/λ ≈ Δf/f ≈ v/c

9701 · 2025–2027

Chemistry reference data

Numerical constants and qualitative-analysis observations in one compact sheet.

Official course page ↗

For the current 2025–2027 syllabus, the former Chemistry Data Booklet is no longer issued with Papers 1, 2 and 4. Treat this as a revision reference, not a list of data guaranteed to be printed in the exam.

Useful numerical data

Quantity	Value
Avogadro constant, N_A	6.02 × 10²³ mol⁻¹
Molar gas constant, R	8.31 J K⁻¹ mol⁻¹
Faraday constant, F	9.65 × 10⁴ C mol⁻¹
Ionic product of water, K_w	1.00 × 10⁻¹⁴ mol² dm⁻⁶ at 298 K
Molar gas volume at room conditions	24.0 dm³ mol⁻¹
Specific heat capacity of water	4.18 J g⁻¹ K⁻¹

Common formulae

Amountn = m/M

Concentrationc = n/V

Ideal gaspV = nRT

Calorimetryq = mcΔT

Enthalpy per moleΔH = −q/n

pHpH = −log₁₀[H⁺]

Acid dissociationKₐ = [H⁺][A⁻]/[HA]

Gibbs energyΔG = ΔH − TΔS

ElectrolysisQ = It

Electrode potentialE°cell = E°right − E°left

Qualitative analysis: ions and gases

Species	Test	Positive observation
NH₄⁺	Add aqueous NaOH; warm	Ammonia evolved; damp red litmus turns blue
CO₃²⁻	Add dilute acid	Effervescence; CO₂ turns limewater milky
Cl⁻ / Br⁻ / I⁻	Acidify with dilute HNO₃, then add AgNO₃	White / cream / yellow precipitate
SO₄²⁻	Acidify, then add aqueous Ba²⁺	White precipitate
H₂	Apply a lighted splint	Squeaky pop
O₂	Insert a glowing splint	Splint relights
CO₂	Bubble through limewater	Limewater turns milky
NH₃	Use damp red litmus	Litmus turns blue

9701 · chemistry reference

Periodic table

A separate quick-reference tab for element symbols and the group patterns used throughout CIE A Level Chemistry.

9701 course page ↗

The interactive table from the 9701 Chemistry notes. Select an element to view its atomic mass, group, period, electron configuration and common oxidation states.

Elements by period

Period	Elements
1	H hydrogen · He helium
2	Li lithium · Be beryllium · B boron · C carbon · N nitrogen · O oxygen · F fluorine · Ne neon
3	Na sodium · Mg magnesium · Al aluminium · Si silicon · P phosphorus · S sulfur · Cl chlorine · Ar argon
4	K potassium · Ca calcium · Sc scandium · Ti titanium · V vanadium · Cr chromium · Mn manganese · Fe iron · Co cobalt · Ni nickel · Cu copper · Zn zinc · Ga gallium · Ge germanium · As arsenic · Se selenium · Br bromine · Kr krypton
5	Rb rubidium · Sr strontium · Y yttrium · Zr zirconium · Nb niobium · Mo molybdenum · Tc technetium · Ru ruthenium · Rh rhodium · Pd palladium · Ag silver · Cd cadmium · In indium · Sn tin · Sb antimony · Te tellurium · I iodine · Xe xenon
6	Cs caesium · Ba barium · lanthanoids (La–Lu) · Hf hafnium · Ta tantalum · W tungsten · Re rhenium · Os osmium · Ir iridium · Pt platinum · Au gold · Hg mercury · Tl thallium · Pb lead · Bi bismuth · Po polonium · At astatine · Rn radon
7	Fr francium · Ra radium · actinoids (Ac–Lr) · Rf rutherfordium · Db dubnium · Sg seaborgium · Bh bohrium · Hs hassium · Mt meitnerium · Ds darmstadtium · Rg roentgenium · Cn copernicium · Nh nihonium · Fl flerovium · Mc moscovium · Lv livermorium · Ts tennessine · Og oganesson

Exam-useful groups

Group	What to remember
2	Be, Mg, Ca, Sr, Ba — outer-shell configuration ns²; hydroxide solubility increases down the group.
7 / 17	F, Cl, Br, I — halogens; oxidising power decreases down the group, while halide ions become stronger reducing agents.
18	He, Ne, Ar, Kr, Xe — noble gases; full outer shell and very low reactivity.
d-block	Sc–Zn and related transition elements — variable oxidation states, coloured compounds and complex-ion chemistry are most exam-relevant.

9700 · 2025–2027

Biology mathematical formulae

The A Level formulae Cambridge states candidates will be given when needed, plus degrees-of-freedom formulae that must be known.

Official syllabus ↗

Ecology, genetics and statistics

Hardy–Weinbergp + q = 1

Hardy–Weinbergp² + 2pq + q² = 1

Lincoln indexN = (n₁ × n₂) / m₂

Simpson's diversityD = 1 − Σ(n/N)²

Chi-squaredχ² = Σ((O − E)²/E)

Sample standard deviations = √(Σ(x − x̄)²/(n − 1))

Standard errorSE = s/√n

95% confidence intervalx̄ ± (2 × SE)

Two-sample t-testt = (x̄₁ − x̄₂)/√(s₁²/n₁ + s₂²/n₂)

Pearson correlationr = Σ(x−x̄)(y−ȳ) / ((n−1)sₓsᵧ)

Spearman rankrₛ = 1 − 6ΣD²/(n³ − n)

χ² degrees of freedom · knowv = c − 1

t-test degrees of freedom · knowv = n₁ + n₂ − 2

Symbol key

Symbol	Meaning	Symbol	Meaning
p, q	Allele frequencies	n	Sample size or number of individuals of a type
n₁	Number captured first time	n₂	Total captured second time
m₂	Marked individuals recaptured	N	Estimated population or total individuals
O, E	Observed and expected values	D	Difference between paired ranks

9618 · Paper 2 · 2026

Cambridge pseudocode

Compact syntax reference for declarations, control structures, subroutines and file handling.

Official 2026 guide ↗

Variables, constants & arrays

DECLARE Score : INTEGER
DECLARE Average : REAL
DECLARE Name : STRING
DECLARE Initial : CHAR
DECLARE Found : BOOLEAN

CONSTANT MaxSize = 100
Score ← 0

DECLARE Names : ARRAY[1:30] OF STRING
DECLARE Grid : ARRAY[1:3, 1:3] OF CHAR
Grid[Row, Column] ← 'X'

Selection

IF Score >= 50 THEN
   OUTPUT "Pass"
ELSE
   OUTPUT "Try again"
ENDIF

CASE OF Choice
   1 : OUTPUT "One"
   2 : OUTPUT "Two"
   OTHERWISE : OUTPUT "Unknown"
ENDCASE

Iteration

FOR Index ← 1 TO 10
   OUTPUT Index
NEXT Index

WHILE Value <> 0
   INPUT Value
ENDWHILE

REPEAT
   INPUT Value
UNTIL Value = 0

Procedures & functions

PROCEDURE ShowTotal(BYVAL Total : INTEGER)
   OUTPUT Total
ENDPROCEDURE

CALL ShowTotal(Score)

PROCEDURE AddOne(BYREF Value : INTEGER)
   Value ← Value + 1
ENDPROCEDURE

FUNCTION Square(Value : REAL) RETURNS REAL
   RETURN Value * Value
ENDFUNCTION

Area ← Square(Length)

Operators & functions

Type	Syntax
Arithmetic	`+ − * / DIV MOD`
Comparison	`= <> < <= > >=`
Boolean	`AND OR NOT`
Strings	`RIGHT, LENGTH, MID, LCASE, UCASE`; join with `&`
Numbers	`INT(x), RAND(x)`

Text file handling

OPENFILE "Data.txt" FOR READ
WHILE NOT EOF("Data.txt")
   READFILE "Data.txt", Line
   OUTPUT Line
ENDWHILE
CLOSEFILE "Data.txt"

OPENFILE "Data.txt" FOR APPEND
WRITEFILE "Data.txt", NewLine
CLOSEFILE "Data.txt"