Topic 5 Practice Paper: Pressure — mark scheme
IGCSE · Cambridge IGCSE Physics (Extended (Core + Supplement))
Mark scheme
Pressure
Topic 5 Practice Paper · Maximum mark: 30
Notes for markers
- Award one mark for each point marked [1], up to the marks shown for the part.
- Accept answers worded differently that show the same understanding.
- Units are required where the answer line shows one. ecf: allow an error carried forward.
Section A: Multiple-choice questions[10 marks]
| Question | Answer and marking points | Marks |
|---|---|---|
| Total for Question 1 | 1 | |
| Total for Question 2 | 1 | |
| Total for Question 3 | 1 | |
| Total for Question 4 | 1 | |
| Total for Question 5 | 1 | |
| Total for Question 6 | 1 | |
| Total for Question 7 | 1 | |
| Total for Question 8 | 1 | |
| Total for Question 9 | 1 | |
| Total for Question 10 | 1 |
Section B: Structured questions[20 marks]
| Question | Answer and marking points | Marks |
|---|---|---|
| 11(a) | 2 × 0.015 = 0.030 m². [1] | 1 |
| 11(b) | p = 480 ÷ 0.030 = 16 000 Pa.
| 2 |
| 11(c) | It doubles (to about 32 000 Pa): the same weight now acts through half the contact area, and p = F/A with A halved gives p doubled.
| 2 |
| Total for Question 11 | 5 | |
| 12(a) | p = 3600 ÷ 0.090 = 40 000 Pa.
| 2 |
| 12(b) | The force doubles to 7200 N at the same area, so the pressure doubles to 80 000 Pa.
| 2 |
| 12(c) | Area doubled with the same force halves the pressure to 20 000 Pa.
| 2 |
| Total for Question 12 | 6 | |
| 13(a) | A greater depth of water sits above the valve, so the column of water above it weighs more and pushes harder, increasing the pressure at the valve.
| 2 |
| 13(b) | Δp = ρgΔh = 1000 × 9.8 × 8.0 = 78 400 Pa ≈ 78 kPa.
| 2 |
| 13(c) | 1000 × 9.8 × 2.0 = 19 600 Pa ≈ 20 kPa — one quarter of the earlier value, in proportion to the depth.
| 1 |
| Total for Question 13 | 5 | |
| 14(a) | p = 2400 ÷ 0.0020 = 1 200 000 Pa = 1.2 MPa.
| 2 |
| 14(b) | The small pad’s 1.2 MPa exceeds the 800 kPa threshold and would crack the plinth. The wide pad gives 2400 ÷ 0.60 = 4000 Pa (4 kPa), far below the threshold — choose the wide pad.
| 2 |
| Total for Question 14 | 4 |
— End of mark scheme —