Cambridge IGCSE Physics (0625) Paper 2 — Past Papers, Formulas & Complete Study Guide

📚 Table of Contents

1. Paper 2 Overview & Exam Structure
2. Topic 1 — Motion, Forces & Energy
3. Topic 2 — Thermal Physics
4. Topic 3 — Waves
5. Topic 4 — Electricity & Magnetism
6. Topic 5 — Nuclear Physics
7. Topic 6 — Space Physics
8. Exam Strategies & Tips
9. Past Papers Archive (2016–2024)

1. Paper 2 Overview & Exam Structure

Cambridge IGCSE Physics (syllabus code 0625) is administered by Cambridge Assessment International Education (CAIE) and is one of the most widely studied science qualifications worldwide. Students in Years 10 and 11 (ages 14–16) typically sit this exam, and the qualification is recognised for entry into A-Levels, the International Baccalaureate, and university foundation programmes.

The IGCSE Physics course is offered at two levels: Core and Extended. Core students are eligible for grades C–G, while Extended students can achieve the full range of grades from A* to G. Paper 2 is exclusively for Extended tier students and tests both the core content and the additional Extended subject matter.

Exam Format at a Glance

• Paper type: Multiple Choice (Extended)
• Duration: 45 minutes
• Total marks: 40
• Questions: 40 four-option multiple-choice questions (A, B, C, D)
• Weighting: 30% of the total IGCSE Physics grade
• Calculator: Not permitted in Paper 2
• Formula sheet: Not provided — all formulas must be memorised
• Negative marking: None — always answer every question

Questions in Paper 2 are arranged in syllabus topic order — starting with Motion and ending with Space Physics. This predictable structure lets you mentally orient yourself as you move through the paper. If you feel confident in electricity but less so in thermal physics, you can manage your time accordingly.

Paper 2 is sat alongside Paper 4 (Extended Theory, 2 hours) and Paper 6 (Alternative to Practical). Together these three papers make up the complete Extended tier assessment. Paper 2 and Paper 4 together account for 80% of your grade, making them the most important components to prepare for.

2. Topic 1 — Motion, Forces & Energy

Motion, Forces and Energy is the largest topic in the IGCSE Physics syllabus and usually generates the most questions in Paper 2. It forms the backbone of classical mechanics — the physics of how objects move, what changes their motion, and how energy is stored, transferred, and converted between forms.

2.1 Kinematics — Describing Motion

Kinematics describes motion without asking what causes it. The five key scalar and vector quantities — distance, displacement, speed, velocity, and acceleration — must be clearly understood. Scalar quantities have magnitude only (distance, speed, time, mass, energy, temperature). Vector quantities have both magnitude and direction (displacement, velocity, acceleration, force, weight, momentum).

Distance–time graphs and speed–time graphs are consistently tested. On a distance–time graph, the gradient equals speed; a horizontal line indicates rest; a curve indicates changing speed. On a speed–time graph, the gradient equals acceleration and the area under the graph equals the total distance travelled. Free fall under gravity (ignoring air resistance) produces a constant downward acceleration of \( g \approx 10 \text{ m/s}^2 \) near the Earth's surface.

2.2 Newton's Three Laws of Motion

Newton's First Law: An object remains at rest or moves in a straight line at constant speed unless acted on by a resultant (net) force. This property of matter is called inertia. The greater the mass, the greater the inertia.

Newton's Second Law: The resultant force on an object is equal to the product of its mass and acceleration, in the direction of the resultant force.

Newton's Third Law: When object A exerts a force on object B, object B exerts a force on A that is equal in magnitude, opposite in direction, and of the same type. These are sometimes called "Newton's Third Law pairs" or "action–reaction pairs" — they always act on different objects.

2.3 Weight, Mass & Gravitational Field Strength

Mass is the amount of matter in an object (measured in kg) and is constant everywhere in the universe. Weight is the gravitational force acting on a mass and varies with location. On Earth, \( g \approx 10 \text{ N/kg} \); on the Moon, \( g \approx 1.6 \text{ N/kg} \).

2.4 Momentum & Impulse

Momentum is a vector quantity representing the "quantity of motion" of an object. The principle of conservation of momentum states that the total momentum of a closed (isolated) system is constant — no external forces may act on the system. This principle is essential for solving collision and explosion problems.

2.5 Turning Effects, Moments & Pressure

The moment of a force about a pivot is the product of the force and the perpendicular distance from the line of action of the force to the pivot. The principle of moments states that for an object in rotational equilibrium, the sum of clockwise moments equals the sum of anti-clockwise moments about any point.

2.6 Work, Kinetic Energy, Potential Energy & Power

The law of conservation of energy states that energy cannot be created or destroyed — only transformed from one form to another. In any real system, some energy is always dissipated as thermal (heat) energy due to friction or air resistance, which reduces efficiency. A perfectly efficient machine would have efficiency = 100%, but this is impossible in practice.

3. Topic 2 — Thermal Physics

Thermal physics explains how energy is stored and transferred at the particle level. A firm grasp of the kinetic particle model underpins all of this topic, from gas laws to heat transfer mechanisms.

3.1 The Kinetic Particle Model

All matter is composed of particles (atoms or molecules) in constant, random motion. The state of matter — solid, liquid, or gas — depends on the arrangement and energy of these particles. In a solid, particles vibrate about fixed positions; in a liquid, particles move randomly but remain close together; in a gas, particles move rapidly and are far apart with negligible forces between them.

Temperature is a measure of the mean kinetic energy of the particles. As temperature rises, particles move faster on average. Brownian motion — the random, jittery movement of pollen grains or smoke particles visible under a microscope — is direct evidence for the existence of fast-moving invisible particles. Diffusion is the net movement of particles from a region of higher concentration to a lower one, and it occurs faster in gases than liquids because particles move more freely.

3.2 Temperature Scales

The Celsius scale (\(°C\)) is defined by two fixed points: 0°C (ice point — pure melting ice at standard pressure) and 100°C (steam point — steam from boiling pure water at standard pressure). The Kelvin scale (K) is the absolute thermodynamic scale, with 0 K defined as absolute zero — the lowest theoretically possible temperature, at which particles have minimum internal energy.

3.3 The Gas Laws

For a fixed mass of gas, three experimental laws describe how pressure, volume, and temperature relate to one another when one variable is held constant. All gas law calculations involving temperature must use Kelvin, not Celsius.

3.4 Specific Heat Capacity & Specific Latent Heat

Specific latent heat of fusion (\(L_f\)) is the energy per unit mass required to change a solid into a liquid at constant temperature (melting/freezing). Specific latent heat of vaporisation (\(L_v\)) is the energy per unit mass needed to change a liquid into a gas at constant temperature (boiling/condensation). During any change of state, temperature remains constant — energy goes into breaking or forming intermolecular bonds, not raising temperature.

3.5 Conduction, Convection & Radiation

Heat transfers by three mechanisms. Conduction occurs mainly in solids: vibrating particles pass energy to neighbouring particles; metals are excellent conductors because their free electrons carry energy rapidly. Convection occurs only in fluids (liquids and gases): heated fluid expands, becomes less dense, rises , and cooler fluid sinks to replace it, forming a convection current. Radiation is the transfer of energy by infrared electromagnetic waves — it requires no medium (it travels through a vacuum). Dark, matte surfaces are better emitters and absorbers of radiation; light, shiny surfaces are better reflectors and poor emitters.

4. Topic 3 — Waves

Waves transfer energy from one place to another without transferring matter. This topic covers sound waves, light waves, the full electromagnetic spectrum, reflection, refraction, diffraction, and wave properties. It also includes optical instruments and the behaviour of light at boundaries between media.

4.1 General Wave Properties

Transverse waves oscillate perpendicular to the direction of energy propagation (e.g., light, water ripples, all electromagnetic waves). Longitudinal waves oscillate parallel to the direction of energy propagation, creating compressions and rarefactions (e.g., sound waves). Key wave quantities are amplitude, wavelength, frequency, period, and wave speed.

4.2 Reflection, Refraction & Snell's Law

When a wave hits a boundary between two media, part of its energy is reflected and part is refracted (transmitted and changes direction). The law of reflection states that the angle of incidence equals the angle of reflection, both measured from the normal. Refraction occurs because wave speed changes between media — light slows down when entering a denser optical medium, bending toward the normal.

Total Internal Reflection (TIR) occurs when light travels from a denser to a less dense medium and the angle of incidence exceeds the critical angle. The light is completely reflected back into the denser medium — no refraction occurs. TIR is exploited in optical fibres (telecommunications, endoscopes) and diamond cutting to maximise brilliance.

4.3 The Electromagnetic Spectrum

All electromagnetic (EM) waves travel at the speed of light \( c \approx 3 \times 10^8 \text{ m/s} \) in a vacuum. They are transverse waves and require no medium. Arranged in order of increasing frequency (decreasing wavelength), the EM spectrum consists of: Radio waves → Microwaves → Infrared → Visible light → Ultraviolet → X-rays → Gamma rays.

4.4 Sound Waves

Sound is a longitudinal mechanical wave that requires a medium (solid, liquid, or gas) to propagate — it cannot travel through a vacuum. The speed of sound depends on the medium: approximately 340 m/s in air at room temperature, about 1500 m/s in water, and over 5000 m/s in steel. The audible frequency range for humans is approximately 20 Hz to 20,000 Hz (20 kHz). Frequencies above 20 kHz are ultrasound, used in sonar, medical imaging (echocardiography), and industrial flaw detection. The distance formula using echo timing is:

5. Topic 4 — Electricity & Magnetism

Electricity and Magnetism is the second largest topic in Paper 2 and a rich source of formula-based questions. It spans electrostatics, DC circuit analysis, resistance, energy and power calculations, and electromagnetic induction.

5.1 Electric Charge, Current & Potential Difference

Electric charge (\( Q \)) is measured in coulombs (C). Conventional current is defined as the flow of positive charge — in the direction opposite to the flow of electrons. Potential difference (voltage, \( V \)) is the energy transferred per unit charge between two points in a circuit. The electromotive force (e.m.f.) of a source is the energy provided per unit charge to drive charge around the circuit.

5.2 Ohm's Law & Resistance

Ohm's Law states that the current through a conductor is directly proportional to the potential difference across it, provided physical conditions (especially temperature) remain constant. Ohmic conductors obey this law — a resistor at constant temperature is an example. Non-ohmic conductors include filament lamps (resistance increases with temperature) and diodes (conduct in one direction only).

5.3 Series & Parallel Circuits

5.4 Electrical Power & Energy

5.5 Electromagnetic Induction & Transformers

An e.m.f. is induced in a conductor when the conductor cuts magnetic field lines, or when the magnetic flux through a coil changes. This is Faraday's Law. The induced e.m.f. can be increased by: increasing the speed of movement, increasing the number of turns on the coil, or using a stronger magnet. Lenz's Law states that the induced current always opposes the change causing it (conservation of energy).

A transformer uses electromagnetic induction to step AC voltage up or down. Ideal (100% efficient) transformer equations are:

6. Topic 5 — Nuclear Physics

Nuclear Physics explores the structure of the atom, radioactive decay, and the properties of the three types of ionising radiation. Paper 2 typically includes 4–6 questions from this topic, testing knowledge of alpha, beta, and gamma radiation as well as nuclear equations and half-life.

6.1 Atomic Structure

An atom consists of a tiny, dense, positively charged nucleus surrounded by negatively charged electrons in shells. The nucleus contains protons (positively charged) and neutrons (no charge). The proton number (Z) — also called atomic number — gives the number of protons and defines the element. The nucleon number (A) — also called mass number — is the total number of protons and neutrons. Nuclide notation:

6.2 The Three Types of Radioactive Radiation

6.3 Nuclear Decay Equations

6.4 Half-Life

Radioactive decay is a random and spontaneous process — it cannot be triggered or stopped by external conditions (temperature, pressure, chemical state). The half-life (\(t_{1/2}\)) of a radioactive isotope is the time taken for half the nuclei in a sample to decay, reducing the activity or count rate by half.

7. Topic 6 — Space Physics

Space Physics was added to the IGCSE Physics syllabus in the 2016 revision. It covers the life cycles of stars, the structure of the universe, and the evidence for the Big Bang. Paper 2 typically features 2–4 questions from this topic.

7.1 The Solar System & Beyond

Our Solar System consists of the Sun (a medium-sized star), eight planets, dwarf planets, moons, asteroids, and comets. The Sun sits at the centre; planets orbit it in elliptical paths. Distances in space are measured in light-years (the distance light travels in one year: \( \approx 9.46 \times 10^{15} \text{ m} \)) or astronomical units (AU — the mean Earth–Sun distance: \( \approx 1.5 \times 10^{11} \text{ m} \)). Our Solar System belongs to the Milky Way galaxy, which is one of billions of galaxies in the observable universe.

7.2 Stellar Life Cycles

Stars form from clouds of gas and dust called nebulae. Gravity causes a nebula to contract, heating the core until nuclear fusion begins — the star enters the stable main sequence phase (like our Sun). The fate of a star after the main sequence depends on its mass:

• Small/medium star (like the Sun): Red giant → White dwarf → Black dwarf
• Massive star: Red supergiant → Supernova explosion → Neutron star or Black hole

7.3 The Big Bang & Red Shift

The Big Bang theory states that the universe began approximately 13.8 billion years ago from an extremely hot, dense point and has been expanding ever since. The main evidence for this is red shift: light from distant galaxies is shifted toward the red (longer wavelength) end of the spectrum, indicating they are moving away from us. The more distant the galaxy, the greater its red shift and the faster it recedes — Hubble's Law. Additionally, the cosmic microwave background radiation (CMBR) — a faint, uniform microwave radiation detected from all directions — is considered the thermal afterglow of the Big Bang.

8. Exam Strategies & Tips for Paper 2

8.1 Time Management

You have 45 minutes for 40 questions — roughly 67 seconds per question. In practice, about 30–40% of questions are instant recall (under 20 seconds) and 20–30% require a short calculation (up to 90 seconds). Budget your time: aim to finish a first pass in 30 minutes, then review flagged questions in the remaining 15 minutes.

8.2 Strategy for Difficult Questions

1. Read the question stem carefully — identify the topic and the physics principle being tested.
2. Eliminate obviously wrong answers immediately.
3. Use unit analysis (dimensional analysis) to verify formulae on the fly.
4. Watch for qualifier words: always, never, only, mainly — these often signal a trap answer.
5. If genuinely unsure between two options, trust your first instinct and move on.

8.3 Common Mistake Areas

• Forgetting to convert Celsius to Kelvin in gas law calculations.
• Confusing mass and weight — weight is a force (N); mass is measured in kg.
• Mixing up series and parallel rules for resistors vs. capacitors.
• Using diameter instead of radius when calculating area.
• Forgetting the factor of ½ in \( E_k = \frac{1}{2}mv^2 \) and kinetic energy problems.
• Misidentifying the direction of conventional current (opposite to electron flow).

9. Past Papers Archive (2016–2024)

All Cambridge IGCSE Physics (0625) Paper 2 past papers and mark schemes below are sourced from Dynamic Papers. Use the filter buttons to quickly navigate to a specific exam session.