Command words

The verb in a question tells you what the examiner wants. Answering the wrong kind of thing — describing when you were asked to explain, or skipping the working on a ‘show that’ — is one of the easiest ways to lose marks you could have had.

Recall — just state the fact

State / Give / Write down: Give a brief fact or answer with no explanation and no working. One line is enough. “State the unit of magnetic flux.” — the weber (Wb).
Name: Identify something with a word or short phrase.
Define: Give the precise meaning, often as a word equation or a ‘… is …’ statement. Use the exact terms the mark scheme expects. “Define gravitational field strength.” — the force per unit mass on a small test mass at that point.

Work it out — numbers

Calculate: Work out a numerical answer. Show your working and give a unit, and watch your significant figures.
Determine: Calculate a value, often using data or a reading taken from a graph.
Estimate: Get an answer of the right order of magnitude using sensible assumptions; usually one significant figure is fine.
Show that: Arrive at a result you have already been given. Show every step, and quote your answer to one more significant figure than the given value to prove you did the work. “Show that g ≈ 9.8 N kg⁻¹…” — end with 9.81 to show it really comes out.

Reason — in words

Describe: Say what happens or what something looks like. No reasons are needed — just an accurate account.
Explain: Give the reason or mechanism — a cause and effect, usually signalled by ‘because’. A description on its own will not score. ‘The current falls’ describes; ‘the current falls because the p.d. across the resistor drops’ explains.
Suggest: Apply what you know to an unfamiliar situation and give a reasoned answer. There may be more than one acceptable response.
Compare: Give both similarities and differences, and make each point about both things together, using words like ‘whereas’ or ‘both’.
Justify / Deduce: Support a statement or conclusion with evidence or reasoning, or draw a conclusion that follows from the information given.

Graphs and judgement

Sketch: Draw the correct shape with axes labelled and key features (intercepts, asymptotes, turning points) marked. It need not be to scale, but the proportions should be right.
Plot: Mark the given data points accurately on the axes provided, then draw the line or curve of best fit.
Evaluate: Weigh the points for and against, or the strengths and limitations, and give a supported overall conclusion.

See also the key ideas for each topic and the revision checklist.