Exam practice

Command words

The single most common reason a student who knows the Physics still drops marks: they answered a different question from the one that was set. These are the command words Cambridge uses and what each one actually demands. Train them until reading the command word is automatic.

The command words, and what each one is really asking for

Command wordWhat it meansWhat that looks like in an exam answer
AssessMake an informed judgement.A judgement with support - not just an opinion.
CalculateWork out from given facts, figures or information.Show the working. A bare number with no method can lose the mark.
CommentGive an informed opinion.State your view, then back it with a reason from the topic.
CompareIdentify and comment on similarities and/or differences.You must give both sides - describing only one caps your marks.
ContrastIdentify and comment on differences.Differences only, but still both sides.
DefineGive precise meaning.One precise sentence. Do not describe or give examples instead.
DescribeState the points of a topic, give characteristics and main features.What it is and what it involves. No reasons required.
DetermineEstablish an answer using the information available.Use the data or information given, not recall.
DiscussWrite about the issue or topic in depth in a structured way.Both sides, organised, with a conclusion.
EvaluateJudge the quality, importance, amount or value of something.Weigh it up and reach a supported judgement. No judgement, no top mark.
ExplainSet out purposes or reasons, make relationships clear, say why and/or how, and support with relevant evidence.Every point needs a reason or consequence. This is where most marks are lost.
GiveProduce an answer from a given source, or recall from memory.Short and direct.
IdentifyName, select or recognise.Just the answer - no explanation needed.
JustifySupport a case with evidence or argument.A claim plus the evidence that supports it.
OutlineSet out the main points.Brief points, no development.
PredictSuggest what may happen based on the information available.Use the information given, not guesswork.
Show (that)Provide structured evidence that leads to a given result.Work through the steps so the result follows.
SketchMake a simple freehand drawing showing the key features, taking care over proportions.Label it. Proportions matter more than artistic quality.
StateExpress in clear terms.One clear fact per mark. Do not waste time developing it.
SuggestApply knowledge and understanding to situations where there are a range of valid responses, in order to make proposals or put forward considerations.Apply it to the situation given - that is what is being tested.
Cambridge publishes these command words in the 9702 syllabus. At AS & A Level the marks usually sit in the equation, the substitution, the unit and the reason - state, show, calculate and explain are where most marks are won and lost.

The difference that matters most

Look at the same knowledge asked three ways. Same topic, three different answers, three different marks.

CommandQuestionAnswer that scores full marks
State (1)State the SI base unit of force.The kilogram metre per second squared (kg m s-2), known as the newton.
Show (2)Show that the kinetic energy of a body can be written as p2/2m, where p is its momentum and m its mass.Kinetic energy = 1/2 m v2 and momentum p = m v, so v = p/m; substituting, 1/2 m (p/m)2 = p2/2m, so Ek = p2/2m.
Explain (3)Explain why the current in a filament lamp increases non-linearly as the potential difference across it is increased.Increasing the potential difference increases the current, which raises the rate at which electrical energy is transferred to thermal energy in the filament; the temperature of the filament therefore rises, so the lattice ions vibrate more, the electrons collide with them more often, and the resistance increases, so the current rises more slowly than the potential difference.
Learn this pattern. Fact. Then consequence. Then the context. Almost every lost mark is a missing middle step.

Command-word trainer

Read the question, decide what the command word demands, write the answer, then compare it with the model answer.