HIGH SCHOOL PHYSICS MASTER BANK
Final-Week Revision Edition — FINAL EXAM HACKS
HOW TO USE THIS IN YOUR FINAL WEEK
Same system as the Chemistry bank: organized by topic cluster (e.g a mix of density with
machines in one structured question).
For each cluster: core facts, key equations, worked examples, and exam traps.
Rhythm: 2–3 clusters/day in the morning, past paper questions on those clusters in the afternoon,
traps list before bed.
PART 0: QUICK-REFERENCE SHEET (memorize this page cold)
Constants
g (acceleration due to gravity) = 10 m/s² (use 9.8 if the paper specifies; the examiner usually
gives you the value to use)
Speed of light in vacuum, c = 3 × 10⁸ m/s
Speed of sound in air ≈ 330–340 m/s (varies with temperature — will be given if needed)
Density of water = 1000 kg/m³ (1 g/cm³)
Atmospheric pressure ≈ 1.0 × 10⁵ Pa (760 mmHg = 76 cmHg)
Master formulae by theme
Mechanics
Density = Mass ÷ Volume (ρ = m/V)
Weight = mass × g (W = mg)
Speed = Distance ÷ Time; Velocity = Displacement ÷ Time
Acceleration = (v − u) ÷ t
Equations of linear motion (constant acceleration): v = u + at; s = ut + ½at²; v² = u² + 2as
Force = mass × acceleration (F = ma)
Momentum = mass × velocity (p = mv); Impulse = Ft = change in momentum
Work = Force × distance moved in direction of force (W = Fd)
Power = Work ÷ Time (P = W/t)
Kinetic energy = ½mv²; Potential energy = mgh
Efficiency (%) = (useful output energy/work ÷ input energy/work) × 100
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Moment of a force = Force × perpendicular distance from pivot
Principle of moments (equilibrium): sum of clockwise moments = sum of anticlockwise
moments
Pressure
Pressure = Force ÷ Area (P = F/A)
Pressure in a fluid = ρgh (density × g × height/depth)
Boyle's Law: P₁V₁ = P₂V₂ (constant temperature)
Combined gas law: P₁V₁/T₁ = P₂V₂/T₂ (T always in Kelvin)
Heat
Heat gained/lost, Q = mcΔθ (mass × specific heat capacity × temperature change)
Heat for a change of state, Q = mL (mass × specific latent heat)
Linear expansivity: expansion = original length × α × temperature change
Waves & Light
Wave equation: v = fλ (speed = frequency × wavelength)
Refractive index, n = sin i ÷ sin r (angle of incidence ÷ angle of refraction) — also n = speed
in vacuum ÷ speed in medium
Lens formula: 1/f = 1/u + 1/v (f=focal length, u=object distance, v=image distance)
Magnification = image height ÷ object height = v/u
Electricity
Ohm's Law: V = IR (Voltage = Current × Resistance)
Power (electrical) = VI = I²R = V²/R
Energy (electrical) = Power × time (in Wh or J, watch units: 1 kWh = "1 unit")
Series circuits: same current throughout; voltages add; R_total = R₁+R₂+R₃...
Parallel circuits: same voltage across each branch; currents add; 1/R_total =
1/R₁+1/R₂+1/R₃...
Charge, Q = It (charge = current × time)
Key unit reminders
Always convert: cm→m (÷100), g→kg (÷1000), minutes→seconds (×60), °C→K (+273),
cm²→m² (÷10,000)
A. MEASUREMENTS & PHYSICAL QUANTITIES
Core facts
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Fundamental (base) quantities: length (m), mass (kg), time (s), temperature (K), electric
current (A) — all other quantities are derived from these.
Instruments and their precision: metre rule (±0.1cm), vernier calipers (±0.01cm, reads
internal/external diameters and depths), micrometer screw gauge (±0.01mm, for very
small/thin objects — has a ratchet to avoid over-tightening).
Vernier calipers reading: main scale reading + (vernier scale division that aligns × 0.01cm).
Micrometer screw gauge reading: main scale (sleeve) reading + (thimble scale reading ×
0.01mm), watch for zero error (adjust final reading by adding/subtracting the zero error).
Significant figures and estimation of error matter in practical papers (Paper 3).
Worked examples
1. A micrometer screw gauge has a zero error of +0.02mm (reads +0.02 when jaws are
closed). A measurement gives a reading of 5.36mm. Find the actual/corrected reading. →
Actual reading = observed reading − zero error = 5.36 − 0.02 = 5.34mm
2. Vernier calipers: main scale reads 2.3cm, and the 4th vernier division aligns with a main
scale line. → Reading = 2.3 + (4 × 0.01) = 2.34 cm
3. State why a set-square and metre rule combination is used to measure the diameter of a
spherical object rather than a metre rule alone. → A metre rule alone cannot give an
accurate reading of a curved edge since it's hard to align the zero mark exactly at the tangent
point; set-squares placed against both sides of the sphere allow the diameter to be read off
perpendicular to the rule accurately.
Exam traps
Zero error sign convention: if the reading when jaws/screw are closed is POSITIVE, you
SUBTRACT it; if NEGATIVE, you ADD it (subtracting a negative). Getting this backwards
is the #1 error here.
Vernier caliper reading formula uses 0.01cm per division; micrometer uses 0.01mm per
division — don't mix them up.
B. FORCE, MASS, WEIGHT & DENSITY
Core facts
Mass = amount of matter in a body, constant everywhere (measured with a beam balance).
Weight = force of gravity on a mass (W=mg), varies with location (less on the moon due to
lower g), measured with a spring balance.
Density = mass ÷ volume; relative density = density of substance ÷ density of water (no
units, it's a ratio).
Finding volume of an irregular solid: displacement method (submerge in a eureka
can/measuring cylinder, volume = volume of water displaced).
Types of forces: gravitational, frictional, tension, upthrust, electrostatic, magnetic, normal