中文（繁體）
中文（简体）
English
S4 Physics: Heat Capacity and Heat Transfer Paper 4 (everyday use, flow rates and radiation)
S4 Physics: Heat Capacity and Heat Transfer Paper 4 (everyday use, flow rates and radiation)
Paper 4 leaves the classroom: heaters, heating curves, heat loss and radiation, all tracked with the same E = mc dT.
Quick answer 315 kJ; 28,800 J; radiation needs no medium and crosses a vacuum; dark rough surfaces; 7 minutes; 100 C; 70 per cent; 14.3 C; 23.1 C; heat capacity and specific heat capacity have different units.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 questions |
| Suggested time | 25 minutes |
| Difficulty mix | Foundation 4 · Intermediate 3 · Challenge 2 · Error redo 1 |
| Chapter | Chapter: S4 Physics: Heat Capacity and Heat Transfer |
| Level | S4 |
02 Questions (10 items)
- Foundation1.5 kg of water is heated from 30 C to 80 C. Find the energy needed at 4,200 J per kg per degree.
- Foundation0.8 kg of aluminium rises 40 degrees. Find the energy absorbed at 900 J per kg per degree.
- FoundationWhat most distinguishes radiation from conduction and convection?
- FoundationWhich colour and texture absorbs radiant heat best?
- IntermediateA 2 kW heater raises 4 kg of water from 20 C to 70 C. Ignoring losses, how many minutes does it take?
- IntermediateOne kilogram of water rises from 20 C to 60 C in 5 minutes at constant power. After another 5 minutes at the same power, what is the temperature?
- IntermediateA heater takes in 300 kJ and the water absorbs 210 kJ. Find the efficiency.
- ChallengeAn instant heater runs at 3 kW with a flow of 0.05 kg per second. By how much does the water warm, to one decimal place?
- ChallengeA 300 W heater runs 3 minutes in 0.5 kg of water with 10 per cent lost. Find the temperature rise to one decimal place.
- Error redoA student writes the heat capacity of a body of water as 12,600 J per kg per degree. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 315,000 J (315 kJ) | The rise is 50 degrees, so 1.5 times 4,200 times 50 gives 315,000 J. |
| 2 | 28,800 J | 0.8 times 900 times 40 gives 28,800 J. |
| 3 | Radiation is electromagnetic waves and needs no medium, so it crosses a vacuum | Conduction and convection need particles while radiation does not, so the Sun reaches us through space. |
| 4 | Dark and rough, such as matt black | Dark rough surfaces absorb strongly while pale shiny ones reflect most of the radiation. |
| 5 | 7 minutes | The energy is 840,000 J, which at 2,000 W takes 420 s, or 7 minutes. |
| 6 | 100 C | Each 5 minutes adds 40 degrees, so from 60 C the next 5 minutes reach 100 C. |
| 7 | 70 per cent | 210 over 300 is 0.7, or 70 per cent, with the remaining 90 kJ lost to air and container. |
| 8 | 14.3 C | Each second supplies 3,000 J, so per kilogram it gives 3,000 over 210, or 14.3 degrees. |
| 9 | 23.1 C | The supply is 54,000 J, 90 per cent of it is 48,600 J, and dividing by 2,100 gives 23.1 degrees. |
| 10 | Heat capacity is in J per degree, while J per kg per degree belongs to specific heat capacity. | Heat capacity already includes the mass, so no per-kilogram term appears; mixing the units hides a factor of m. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Find a tutor freeTutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.
