A-Level · 26 September 2026 · 6 min read
Edexcel IAL Physics Unit 1 and Unit 2: what to study and how to prepare
A unit title tells you where a topic belongs, but it does not yet tell you how to learn it. A student can finish all the Unit 1 notes and still struggle to choose an equation; another can memorise Unit 2 definitions but lose the connection between a circuit diagram and what a meter measures.
This guide turns the two unit labels into a study process with original examples. It refers to the 2018 IAL specification used for students starting in September 2026. Confirm the specification version with your centre if you are joining a later course, and use the official document as the complete content checklist.
Make a topic map and a skill map
For Unit 1, organise mechanics and materials into manageable topics, then connect each to the decisions needed in a question: identifying a resultant force, selecting an energy argument, interpreting a motion graph or relating a material's extension to its dimensions. For Unit 2, organise waves, the particle nature of light and electric circuits in the same way.
Beside each topic, record four forms of evidence: a labelled diagram, an explanation in words, a calculation and a practical or graph question. A tick for 'read the chapter' does not establish that you can do those things. This second map reveals why a familiar topic can still produce low marks in an unfamiliar format.
Unit 1: practise the model before the arithmetic
Try this original example. A 1.2 kg object moves horizontally with a 5.0 N applied force and a 1.4 N opposing resistance. The resultant is 3.6 N, giving a = 3.6/1.2 = 3.0 m s⁻². A diagram separates the two horizontal forces and helps prevent substituting 5.0 N directly into F = ma. Vertical equilibrium is a separate statement about the vertical forces.
Now ask what changes if resistance grows with speed. You should not continue treating the acceleration as constant without checking the conditions. The equation F = ma still describes the instantaneous relationship, but constant-acceleration motion equations need their own justification. This habit of stating the model matters more than memorising a fixed order of formulas.
Unit 1: connect the material graph to physical meaning
Suppose a spring's force–extension graph is a straight line through the origin and reaches 12 N at an extension of 0.030 m. Its stiffness is the gradient, 12/0.030 = 400 N m⁻¹. The elastic energy represented by the area is ½ × 12 × 0.030 = 0.18 J for this linear loading region. The same diagram answers two different questions because gradient and area have different meanings.
Change the horizontal unit to millimetres and the numerical gradient changes, even though the physical spring does not. This is a useful check that you understand the axes rather than merely recognising the graph's shape. When the graph ceases to be linear, revisit which relationships remain valid instead of extending a straight-line formula automatically.
Unit 2: link waves and circuits to measurable quantities
For a wave travelling at 340 m s⁻¹ with frequency 850 Hz, the wavelength is v/f = 0.40 m. Then explain what changes when a wave crosses into a different medium: the source fixes the frequency, while speed and wavelength can change. The calculation and the explanation should support each other; knowing one does not guarantee the other.
For a simple series circuit with ideal 6.0 V supply and resistors of 2.0 Ω and 4.0 Ω, the total resistance is 6.0 Ω and the current is 1.0 A. The potential differences are 2.0 V and 4.0 V. Their sum matches the supply. State the ideal-source assumption and distinguish the common current from the different energy transferred per unit charge across each resistor.
Build practical reasoning alongside the topic
When learning a relationship, ask how you would test it. For a force–extension investigation, identify what changes, what is measured and how you would check for an offset in the extension reading. For a circuit investigation, draw how the measuring instruments connect and explain how a changing temperature could affect the result.
This does not replace supervised practical experience or the official core-practical requirements. It prevents practical reasoning from being treated as a separate vocabulary list at the end of the course. Keep a record of actual experiments and label any invented practice data as practice data. Use the dedicated Unit 3 guide for assessment-focused preparation.
Use a repeatable preparation cycle
Choose one topic and attempt a small question before opening the notes. Read or watch only enough to address the gap, then solve a different question independently. Mark the attempt, name the error and schedule a later retry. Once several topics are secure, mix them so you must decide which model applies rather than relying on a worksheet title.
Near the assessment, practise with the correct WPH11 or WPH12 papers and the conditions your centre confirms. Do not treat completion speed as the only measure: look for repeated unit errors, unexplained assumptions and missing reasoning. For course support, bring the marked attempt and the question you could not resolve. That gives a teacher a more useful starting point than 'I need help with all of Unit 2'.
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.
What is in Edexcel IAL Physics Unit 1?
For the 2018 specification, WPH11 is Mechanics and Materials. Use the specification for the full scope and practise modelling forces and motion, energy reasoning, graphs and material behaviour. Treat this guide as a study route, not a replacement for the complete official list of assessable content.
What is in Edexcel IAL Physics Unit 2?
For the 2018 specification, WPH12 is Waves and Electricity, including the particle nature of light and electric circuits. Combine explanations with diagrams, numerical questions and practical interpretation. Check the exact specification version before relying on a resource simply labelled Unit 2.
Are Units 1 and 2 enough for International AS Physics?
No. Under the 2018 Edexcel International AS structure, Unit 3 is also required. It assesses practical skills related to the earlier units. Include practical learning in your plan from the start and confirm that your centre has entered you for the complete intended qualification.
Should I revise Unit 1 or Unit 2 first?
Use your assessment schedule and a short diagnostic to decide. Prioritise a weak prerequisite or an approaching paper, but keep some practice from the other unit so it stays accessible. A student losing marks through unit conversion needs a different plan from one who knows the calculations but cannot explain wave behaviour.