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Primary General Studies: Energy and Saving Power (Paper 1 (basics))
Primary General Studies: Energy and Saving Power (Paper 1 (basics))
Paper one starts from basic energy ideas: renewable and non-renewable sources, why saving power matters, and converting watt hours into units, then compares a filament bulb with an LED.
Direct answers For concept questions, name the source first and then explain; for calculations, write power times time before computing.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: Primary General Studies: Energy and Saving Power |
| Level | parts of a closed circuit, conductors against insulators, series against parallel, adding up battery voltage, and electrical safety |
02 Questions (10 items)
- FoundationWhat is a renewable energy source?
- FoundationName two non-renewable energy sources.
- FoundationWhy should we save electricity?
- IntermediateA 60 watt filament bulb is used 4 hours a day. How many watt hours does it use in a day?
- IntermediateA 9 watt LED lamp is also used 4 hours a day. How many watt hours does it use in a day?
- IntermediateA television uses 5 watts on standby for 20 hours a day. How many watt hours are wasted daily?
- ChallengeHow many watt hours apart are the two lamps in one day?
- ChallengeHow many units of electricity does that gap save over 30 days?
- ChallengeHow many units does standby use in a month of 30 days?
- Error redoA classmate says that an LED is just as bright, so it must use the same electricity. Is that right?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | Sources such as solar, wind and water power that nature keeps replenishing. | Nature keeps producing them, so they are not used up for good. |
| 2 | Coal and petroleum (natural gas and uranium also belong here). | They take millions of years to form, so once used they are gone. |
| 3 | It cuts the burning of fossil fuels, which lowers carbon emissions and air pollution. | Every unit of electricity not used means less pollution, and that works faster than cleaning up later. |
| 4 | 240 watt hours, which is 0.24 units of electricity. | Energy used equals power times time: 60 × 4 = 240 watt hours. |
| 5 | 36 watt hours, which is 0.036 units. | The LED has a much lower power rating, so it uses far less energy for the same time. |
| 6 | 100 watt hours. | Standby still draws power: 5 × 20 = 100 watt hours. |
| 7 | 204 watt hours. | 240 − 36 = 204 watt hours. |
| 8 | 6.12 units. | 204 × 30 = 6120 watt hours, and dividing by 1000 gives 6.12 units. |
| 9 | 3 units. | 5 × 20 × 30 = 3000 watt hours, which is 3 units. |
| 10 | No. The brightness is similar but the LED has a much lower power rating, and energy used is power times time. | To compare energy use, look at the wattage and the hours, not only at brightness. |
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.
After paper one, take paper two and sort out series against parallel in one pass.Tutor Registration →
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