IGCSE · 26 September 2026 · 7 min read
IGCSE Physics modular Unit 1 and Unit 2: content, codes and revision
Searching for 'Physics Unit 1' can return International A-Level courses, linear IGCSE papers and modular IGCSE material. For the modular International GCSE discussed here, the qualification is 4XPH1 and the unit codes are 4WPH1 and 4WPH2. Those identifiers are the first filter for your revision resources.
This guide helps you organise the assessed content and practise it usefully. It is not a replacement for the full specification: the topic map below is deliberately compact, while your detailed checklist should use every applicable statement in the official document.
Check the complete component code
Unit 1 is 4WPH1/1P and Unit 2 is 4WPH2/1P. Notice that both paper references end in 1P: it is the 4WPH1 or 4WPH2 part that distinguishes the unit. Each contributes half of the qualification. This prevents a common search mistake in which a student assumes anything called Paper 1 must belong to Unit 1.
Make the code visible on your revision folder, saved paper names and lesson enquiries. If a resource instead says WPH11, it concerns International AS Physics rather than this IGCSE unit. If it says 4PH1/1P, it is the linear IGCSE paper. Similar-looking codes are an administrative detail with a practical consequence: they determine whether your timed practice represents the right assessment.
Unit 1: build connections across the topic map
The broad Unit 1 map is forces and motion, electricity, energy resources and transfers, plus matter content involving density, pressure and changes of state. Study the exact specification statements within those areas, including the bold P material. The modular unit is not restricted to the non-P content of linear Paper 1.
Connect related ideas while preserving their meanings. Work done is an energy transfer; power is its rate. Electrical power connects voltage and current. Density relates mass and volume, while pressure relates force and area. A mixed revision session can ask you to identify which relationship fits several short situations, so that choosing the equation becomes part of the practice.
Unit 2: avoid overlooking the second part of matter
Unit 2 brings together waves, the ideal-gas-molecule part of matter, magnetism and electromagnetism, radioactivity and particles, and astrophysics. The matter topic is split between units. Do not place an entire chapter labelled solids, liquids and gases in Unit 1 and assume there is nothing from that area to revisit for Unit 2.
Organise explanations around a model and the evidence that supports it. For a gas, connect particle motion and wall collisions to pressure. For induction, connect a change in magnetic conditions to an induced voltage. For radioactive decay, separate the random behaviour of an individual nucleus from the predictable statistical pattern in a large sample. Then practise a question that changes one condition.
Worked Unit 1 example: electrical power and transferred energy
An original question describes a 6.0 V supply delivering a steady 0.40 A to a device for 50 s. Power is P = VI = 6.0 × 0.40 = 2.4 W. Energy transferred is E = Pt = 2.4 × 50 = 120 J. An alternative route uses charge: Q = It = 20 C, then E = QV = 20 × 6.0 = 120 J.
The agreement between the methods checks the relationship between the quantities. Now predict what happens if the operating time doubles while voltage and current remain unchanged. Power remains 2.4 W, but energy becomes 240 J. If you doubled the power as well, review the distinction between a rate and a total. This original example illustrates reasoning, not a claim about a forthcoming paper.
Worked Unit 2 example: wave speed without confusing motion
A wave has frequency 25 Hz and wavelength 0.80 m. Its speed is v = fλ = 25 × 0.80 = 20 m/s. If a second wave travels at the same speed with frequency 50 Hz, its wavelength is λ = v / f = 20 / 50 = 0.40 m. Doubling frequency at fixed speed halves wavelength.
State the fixed condition when explaining the trend. Changing frequency does not justify keeping wavelength fixed at the same time if the wave speed is unchanged. Also distinguish the speed of wave propagation from the oscillatory motion of particles in a medium. A clear diagram or explanation should identify which motion the question asks about before using a number.
Practical and mathematical skills belong in both units
Do not reserve experimental thinking for a separate revision week. When studying a relationship, ask how you could measure the quantities, what you would vary, what you would control and how you would judge the resulting data. Written practical questions require a method that fits the actual investigation rather than a memorised list of generic improvements.
For a current–voltage investigation, describe the meter arrangement and consider changes in temperature when interpreting resistance. For a wave measurement, identify how wavelength is obtained and which repeated measurements would reduce the effect of random variation. A good correction explains why an improvement helps, and whether it addresses random variation, a systematic offset or a limitation in the method.
Use a unit checklist that records independent evidence
For each specification area, keep three short records: something you can explain, a question you can solve without prompts and a mistake you still need to revisit. Mark a topic as needing work when the explanation is vague or the solution requires a hint, even if it felt familiar during a lesson. Familiarity and independent performance are different checks.
Build a revision session by selecting one weak area and one previously studied area. Use matched questions from official modular materials or carefully filtered linear resources, then correct your answers and schedule a fresh attempt. When asking for teaching, include the unit code and your attempted work. That gives the teacher a precise starting point and keeps the course support aligned with your exam entry.
Questions, explained
Choose a question for a direct answer, then explore the explanation and supporting resources. Each answer has its own link to save or share.
Is modular IGCSE Physics Unit 2 harder than Unit 1?
The units are designed at the same qualification standard and have equal weighting. Different topic strengths can make one feel harder to a particular student. Compare your independent performance across the content rather than assuming the later unit number means a higher tier.
Do modular Physics students need the bold P content?
Yes. Both modular units include the additional P statements within their assigned content. The linear rule excluding those statements from Paper 1 does not apply to modular Unit 1. Follow the modular specification's own unit map when deciding what to revise.
Why does the Unit 2 Physics paper code end in 1P?
The modular unit is identified by 4WPH2; its component reference is 4WPH2/1P. Unit 1 is 4WPH1/1P. Read the complete reference rather than interpreting the final 1P by itself. The linear paper 4PH1/1P belongs to a different assessment structure.
Where can I find more modular IGCSE Physics practice?
Start with the official modular sample materials and released papers. You can also use relevant linear questions after matching their content to the unit specification. Keep questions outside the current unit separate, and do not use the total score from an unfiltered linear paper as a modular unit result.