Cambridge A-Level Physics 9702: Command words and keywords

Cambridge International A-level Physics (9702) uses the standard Cambridge command words. Mark schemes reward precise physical terminology, correct formulae and units. Method marks are available for correct working even when the final answer is wrong.

Command words in Physics 9702

Command word	What to do	Common mistake
State	Short answer	Overwriting
Define	Precise meaning (often with equation)	Vague
Describe	What happens; no “why”	Adding explanation
Explain	Why/how; use “because”	Only describing
Suggest	Apply to new context	Textbook recall
Calculate	Show working; formula; units	Wrong formula
Show that	Prove given value with calculation	No working
Determine	Numerical answer with working	Guess
Plot	Graph; line of best fit	Wrong scale
Draw	Circuit/ray diagram; correct symbols	Wrong symbols
Sketch	Rough graph/diagram	Too detailed
Predict	What will happen	Unsupported
Compare	Similarities and differences	Listing separately
Evaluate	Judge; conclude with evidence	No conclusion
Deduce	Work out from information	Guess

Keywords examiners look for

Mechanics

Term	Use correctly	Avoid
Velocity	Vector; direction matters	Speed
Acceleration	Change in velocity / time	”Getting faster”
Force	N	Wrong unit
Weight	mg; N	Mass (kg)
Mass	kg	Weight (N)
Momentum	mv; kg m/s	Wrong unit
Impulse	Change in momentum; FΔt	”Force”
Work done	F × d; J	”Effort”
Power	Energy / time; W	”Strength”
Efficiency	(useful / total) × 100%	Wrong formula
Resultant force	Net force	Single force
Centre of mass	Point where mass acts	”Middle”
Moment	Force × perpendicular distance	”Turning effect” (vague)
Torque	Moment of force	Moment
Angular velocity	ω; rad/s	”Spin”
Centripetal force	Towards centre; mv²/r	”Outward force”

Waves and quantum

Term	Use correctly	Avoid
Phase difference	Radians or degrees	”Out of sync”
Coherence	Constant phase difference	”Same”
Interference	Superposition of waves	”Meeting”
Diffraction	Spreading at gap/edge	”Bending”
Photoelectric effect	Electrons ejected by photons	”Light knocks electrons”
Wave-particle duality	Light/electrons as wave and particle	”Both”
Photon	Quantum of EM radiation	”Particle of light”
De Broglie wavelength	λ = h/p	Wrong formula

Electricity and fields

Term	Use correctly	Avoid
Potential difference	Work per unit charge	”Voltage”
e.m.f.	Energy per unit charge from source	Pd
Internal resistance	Resistance of source	”Resistance”
Capacitance	C = Q/V; F	”Stores charge”
Electric field strength	Force per unit charge	”Field”
Magnetic flux	Φ = BA; Wb	”Field”
Flux linkage	NΦ	”Flux”
Faraday’s law	Induced e.m.f. ∝ rate of change of flux	”Flux change”
Lenz’s law	Induced current opposes change	”Opposes”

Nuclear and radioactivity

Term	Use correctly	Avoid
Binding energy	Energy to separate nucleons	”Nuclear energy”
Mass defect	Difference in mass	”Lost mass”
Half-life	Time for half to decay	”Half the time”
Activity	Decays per second; Bq	”Radiation”
Decay constant	λ	”Constant”
Irradiation	Exposed to radiation	Contamination
Contamination	Radioactive material on/in body	Irradiation

Tips for Physics 9702

1. Learn formulae with correct symbols and units
2. Show working in every calculation
3. Check units—convert before substituting
4. Use syllabus terms—check mark scheme
5. Suggest—apply to the specific scenario
6. Past papers + mark schemes show acceptable wording

How Tutopiya helps

Tutopiya supports Physics 9702 with tutors who use past papers and examiner reports. Explore A-level resources or book a free trial.

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Based on Cambridge International A-level Physics 9702 syllabus. Check the latest syllabus for your exam series.