5054_s26_gt — 2026 May-June Physics 5054 Grade Threshold · Cambridge CAIE O Level

Calculations using wrong values from a circuit — applying e.m.f. across one resistor instead of the total resistance

“Most answers assumed that the e.m.f. of 12 V was across the 400 ohm resistor rather than the total resistance of 700 ohm. Candidates needed to use the total resistance to find the current in the circuit.”— 5054 Paper 2, May/June 2023

How to fix: In a series circuit, the e.m.f. of the supply equals the total voltage across ALL components. Always calculate total resistance first (add series resistors), then use V = IR with the total resistance to find the current. Only then use that current to find the voltage across individual resistors.

Confusing momentum with moment of a force, and errors in conservation of momentum calculations

“A significant number of candidates could not define momentum or confused momentum with the moment of a force.”— 5054 Paper 2, May/June 2023

How to fix: Momentum = mass x velocity (a property of a moving object). Moment = force x perpendicular distance from the pivot (a turning effect). In conservation of momentum problems, after a collision where objects stick together, the combined mass is the sum of BOTH masses. Write: m1v1 + m2v2 = (m1 + m2) x v_final.

Giving descriptions instead of physical explanations — stating what happens without saying why

“Many candidates gave detailed explanations for questions, whilst others stated answers rather than explaining them and applying the physical principles.”— 5054 Paper 2, May/June 2023

How to fix: When a question says 'explain', you must give the scientific reason. A description says WHAT happens; an explanation says WHY it happens. For example, do not just say 'the object accelerates' — say 'there is a resultant force acting on the object, so by Newton's second law it accelerates in the direction of the force'.