IGCSE Physics 0625 command words explained

• State: give a clear fact, value or law with no explanation. Example: state the speed of light in a vacuum (3.0 × 10⁸ m/s).
• Give: a short answer from the data or from memory. Example: give the unit of power (W).
• Name: use the exact physics term. Example: name the quantity measured by a voltmeter (potential difference).
• Identify: pick out the right one. Example: identify which letter on the wave diagram shows the amplitude.
• Define: give the precise meaning, often "per unit". Example: density is mass per unit volume.

• Calculate: work out a number from the data. Write the equation, substitute, and give the answer with a unit. Example: a car travels 150 m in 6.0 s, so v = 150 ÷ 6.0 = 25 m/s.
• Determine: get one definite answer from the information, often a graph reading, gradient or area. Example: determine the acceleration from the gradient of a speed–time graph.
• Show that: the answer is printed, so the marks are for your working. Show the equation and substitution and give one more significant figure than printed. Example: show that the weight of a 5.0 kg mass is about 50 N: W = mg = 5.0 × 9.8 = 49 N.

Free lesson: Rearranging equations

• Explain: say why or how, using "because" and a physics idea. Example: a gas pressure rises when heated because the particles move faster and hit the walls more often and with more force.
• Describe: say what happens or what you see, step by step. Example: describe how to measure the density of a stone using a measuring cylinder and a balance.
• Justify: back up an answer with evidence, such as a number or calculation from the data.
• Comment: give an informed opinion and the physics reason behind it.

• Compare: give similarities or differences, mentioning both things. Example: sound travels faster in water than in air.
• Deduce: reach a conclusion from the data given. Point to the clue you used.
• Predict: say what will happen, following the pattern or equation. Example: if frequency doubles at the same speed, the wavelength halves.
• Suggest: apply your physics to an unfamiliar situation. More than one answer can be accepted.

• Sketch: a simple freehand graph or diagram showing key features. Label the axes. Example: sketch the current–voltage graph for a filament lamp.
• Draw: an accurate diagram or graph. Use a ruler for rays and circuit wires, with arrows on rays.
• Complete: fill in every gap in a table, diagram or sentence, and check the units in the headings.

• Calculators are allowed on every paper. Give numerical answers as decimals, not fractions.
• Equation first, then substitution, then answer with its unit.
• Convert units before substituting: 1 km = 1000 m, 1 kW = 1000 W, 1 minute = 60 s.
• Round to 2 or 3 significant figures only at the end.
• Read scales to the nearest half of the smallest division.

Free lessons: Units and prefixes · Significant figures and standard form