From 2027, O-Level Physics is sat as SEC G3 Physics K323. How the 160 marks split across three papers, two worked questions with our own marking points, the topics that cost the most marks, a practical skills checklist and a Sec 3 to Sec 4 plan.
To score A1 in SEC (O-Level) Physics in 2027, your child needs to be strong on all three papers of G3 Physics K323, which replaces 6091: a 40-question multiple choice paper (30%), an 80-mark structured paper (50%) and a 40-mark practical exam (20%). That is 160 marks over 4 hours 35 minutes. About 55% of the theory marks test applying physics to new situations, and only about 15% test pure recall, so memorising notes is not enough. No formula list is mentioned anywhere in the syllabus, and every relationship is written as "recall and apply", so equations have to be known cold. In our experience, A1 students are rarely the ones who know the most. They are the ones who lose the fewest marks to units, graphs and careless working.
Compulsory structured questions, last two worth 20 marks together
1 h 45 min (whole paper)
70
50% (whole paper)
2 Section B
Answer one of two questions
10
3 Section A
1 to 2 compulsory experiments
55 min
20
20% (whole paper)
3 Section B
One compulsory experiment
55 min
20
Share of the K323 grade carried by each paper
Paper 1 multiple choice30 %
Paper 2 structured and free response50 %
Paper 3 practical20 %
03060
SEAB, G3 Physics K323 syllabus for 2027, scheme of assessment.
Paper 2 decides the grade, so time control over 1 hour 45 minutes matters as much as content. One of its last two questions is data-based: a stem of unfamiliar information that your child must read, interpret and use. It cannot be rehearsed from notes.
Pure Physics asks for more application than Combined Science
SEAB sets the theory papers at about 45% knowledge with understanding and about 55% handling information and solving problems. Combined Science is weighted 50 to 50, with more marks for recall.
Pure Physics K323 against the Physics half of Combined Science K326 and K327
Point
Pure Physics K323
Physics in Combined Science
Theory marks for applying and solving
About 55%
About 50%
Theory marks for pure recall
About 15%
About 20%
Physics structured paper
1 h 45 min, 80 marks
1 h 15 min, 65 marks
Practical
1 h 50 min, 40 marks, Physics only
1 h 30 min, 30 marks, shared with the other science
In practice, a K323 student meets more questions set in contexts they have never seen. The Combined Science guide covers the other route.
Worked question 1: a velocity-time graph worth 9 marks
This is a question we wrote in the style of Paper 2 Section A. The marking points are our own scheme, not SEAB's.
Part
Model working
Our marking points
(a)
a = (8.0 - 0) ÷ 4.0 = 2.0 m/s²
M1 change in velocity over time. A1 2.0 m/s² with unit
M1 distance is area under the graph. M1 all three areas correct. A1 72 m
(c)
Average speed = 72 ÷ 12 = 6.0 m/s
M1 total distance over total time (12 s). A1 6.0 m/s
(d)
Deceleration = 8.0 ÷ 2.0 = 4.0 m/s², F = 60 × 4.0 = 240 N
M1 F = ma with the braking acceleration. A1 240 N
Where marks usually go:
In (c), averaging the speeds (0, 8.0 and 0) instead of dividing total distance by total time. The answer looks reasonable, which is why it survives checking.
In (b), using the gradient instead of the area. Gradient of a velocity-time graph is acceleration. Area is displacement.
In (d), quoting 240 N without saying it acts against the motion when a later part asks about direction.
Worked question 2: a transformer and an electricity bill
This one joins electromagnetic induction with practical electricity. The marking points are again our own.
Part
Model answer
Our marking points
(a)
Ns = 2000 × 12 ÷ 240 = 100 turns
M1 Vp/Vs = Np/Ns. A1 100
(b)
I = P ÷ V = 36 ÷ 12 = 3.0 A
B1 3.0 A
(c)
VpIp = VsIs, so Ip = 36 ÷ 240 = 0.15 A
M1 power in equals power out for an ideal transformer. A1 0.15 A
(d)
A steady current gives a constant magnetic field in the iron core. The field linking the secondary coil does not change, so no e.m.f. is induced.
B1 field in core is constant. B1 no changing field, so no induced e.m.f.
(e)
Energy = 0.036 kW × 150 h = 5.4 kWh. Cost = 5.4 × 30 = 162 cents, or S$1.62
M1 power in kW times hours. A1 S$1.62
The answer in (d) is where many students write "d.c. cannot pass through a transformer". That earns nothing. The mark goes to the chain: steady current, steady field, no change, no induced e.m.f. In (e), the common slip is using 36 W instead of 0.036 kW, which gives an answer a thousand times too large.
The topics that cost the most marks, and why
These are the patterns we see most often when marking Sec 4 scripts. They are our observations, not SEAB data.
Topic
Where the marks go
What fixes it
Kinematics graphs
Mixing up gradient and area, or displacement-time and velocity-time graphs
Label every graph question "gradient means, area means" before starting
Dynamics and free body diagrams
Missing forces, or showing an action-reaction pair on one body
Draw only forces acting on the chosen body, each with a labelled arrow
D.C. circuits with thermistors and LDRs
Saying "resistance changes" without saying which way and what happens to the p.d.
Write the full chain: light up, resistance down, share of p.d. down
Electromagnetic induction
Vague "it cuts the field" answers
Say what changes, that an e.m.f. is induced, and which way it opposes the change
Thermal physics
Confusing temperature with internal energy during melting or boiling
Use particle language about potential and kinetic energy
Light
Ray diagrams drawn freehand, or refraction bending the wrong way
Use a ruler, arrows on rays, and the normal drawn first
Units and significant figures
Bare numbers, or 7 figures copied from the calculator
Final answers to 2 or 3 significant figures, always with a unit
Electricity and Magnetism alone holds 7 of the 20 syllabus topics, from Static Electricity to Electromagnetic Induction. A student weak there cannot reach A1 on strength in mechanics alone.
Paper 3 checklist: 40 practical marks to bank
SEAB's syllabus lists the habits Paper 3 examiners look for. We have turned them into a checklist for every school practical.
1Read to full precisionRecord 22.0 °C on a thermometer marked in 1 °C steps, not 22 °C. Record 12.0 cm on a millimetre rule, not 12 cm. Estimate between marks to better than half a division.
2Head every columnPut the quantity and unit in each heading with a slash, such as "l / cm" or "t / s".
3Match significant figuresGive calculated values to the same number of significant figures as the least precise raw reading. Give ratios as decimals to 2 or 3 significant figures.
4Choose sensible scalesUse more than half the graph paper in each direction, with 2 cm representing 1, 2 or 5 units. Label both axes with quantity and unit.
5Plot cleanlyPlot to better than half a small square, using small crosses or circled dots. Large dots lose marks.
6Draw a fair lineA straight best-fit line should have points spread evenly on both sides along its whole length.
7Take a big gradient triangleThe triangle should cover at least half the line. Quote the gradient to 2 or 3 significant figures, with a unit.
8Name real errorsState a specific source of error, how it affects the result, and a practical improvement. "Human error" scores nothing.
Planning is worth 15% of the practical: identifying variables, outlining a method, explaining how the data leads to a conclusion, and stating safety precautions. The syllabus lists sources of error and improvements, not percentage uncertainty calculations, so spend the time on clear, specific error statements.
No formula list: what to memorise
Our O-Level Physics formula sheet is a revision aid for this. Rewrite it from memory weekly in Sec 4 and check it. The syllabus also states that the acceleration of free fall near the Earth is about 10 m/s², and beta radiation means beta-minus particles only.
A Sec 3 to Sec 4 plan for an A1
Sec 3 Term 1 to 2Measurement, kinematics and dynamicsBuild graph habits now. Every velocity-time question gets gradient and area labelled.
Sec 3 Term 3 to 4Energy, pressure, thermal physics and wavesStart a units and definitions list. Do one timed Paper 2 style question a week.
Sec 4 Term 1 to 2Electricity, magnetism and radioactivityThe heaviest block of the syllabus. Join circuits, induction and cost questions in mixed practice.
Sec 4 Term 2 to 3Practical and data-based questionsRun the Paper 3 checklist in every school practical. Practise unfamiliar data stems.
Sec 4 Term 3 to examsFull papers under timePaper 1 in 1 hour, Paper 2 in 1 hour 45 minutes, then mark strictly.
January 2028ResultsSEAB releases SEC results in January of the following year.
SEAB says science practical exams take place before the written papers, which run from October to November. The exact 2027 dates have not been published yet, so check your child's school calendar.
Common questions
What score do you need for A1 in SEC Physics?
SEAB does not publish grade boundaries for G3 Physics, and they can move from year to year. Treat consistent performance across all three papers as the goal, rather than a fixed percentage.
Is a formula sheet given in the O-Level Physics exam?
No formula list is mentioned in the K323 syllabus, and each relationship is described as "recall and apply". Your child must know every equation from memory.
How much is the Physics practical worth from 2027?
Paper 3 is worth 20% of the grade. It is a formal 1 hour 50 minute practical exam for 40 marks, split into two 55-minute sections.
Which Physics topic is hardest to score in?
Electricity and Magnetism covers 7 of the 20 topics, so it carries the most content. In our experience, electromagnetic induction and thermistor circuits lose the most marks to vague explanations.
Do significant figures really cost marks?
Yes. SEAB states that missing units, units on ratios and answers to an unsuitable number of significant figures are liable to be penalised. Two or three significant figures with a unit is a safe default.
When should my child start preparing for the practical?
From Sec 3. The practical is 20% of the grade and is built from habits like recording readings and plotting graphs, which take months to become automatic.
Written by Denzel Tan, Mathematics & Science Tutor, The Singapore Syllabus. Biology undergraduate · 2 years' tutoring experience in Mathematics and Science (Primary 4 to Secondary 4). More about Denzel
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