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P3 General Studies: Hygiene and Infectious Diseases (Paper 3 (challenge))
Tutor Prep Guide · conductors and insulators, power and electricity cost, series and parallel circuits, fuses and earth protection, and safe habits at home
P3 General Studies: Hygiene and Infectious Diseases (Paper 3 (challenge))
Paper three handles deeper ideas: alcohol strength, killing germs by boiling, resistance, the chain of infection and herd immunity, with multi-step calculations.
Direct answers Before calculating, write out the amount and unit at each step, and only at the end turn the answer into per cent, minutes or times.
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: P3 General Studies: Hygiene and Infectious Diseases |
| Level | parts of a closed circuit, conductors against insulators, series against parallel, adding up battery voltage, and electrical safety |
02 Questions (10 items)
- FoundationWhy is disinfecting alcohol usually 70 per cent rather than 95 per cent?
- FoundationWhy does boiling kill germs?
- FoundationWhat is a resistant bacterium?
- IntermediateWhat are three common ways to break the chain of infection?
- IntermediateWhat is herd immunity?
- IntermediateWhy must a whole course of antibiotics be finished?
- ChallengeWashing hands 8 times a day for 20 seconds each time, how many seconds is that in a week, and how many minutes?
- ChallengeA classroom has 30 people and 60.0 per cent of them are vaccinated. How many people is that?
- ChallengeA 250 millilitre bottle of hand wash is used 2 millilitres at a time. How many times will it last?
- Error redoSomeone says a cold can be cured with antibiotics. What is wrong with that?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | Because 70 per cent holds some water, which helps it get into the germ. | Water helps the alcohol pass through the germ coat; a higher strength hardens the coat and works less well. |
| 2 | The heat changes the proteins in the germs and they die. | Boiling water reaches 100 degrees, and most germs cannot survive that heat. |
| 3 | A bacterium that is not killed by the antibiotics usually used. | Using antibiotics wrongly lets the tougher bacteria survive and multiply. |
| 4 | Control the source, cut the route of spread, and protect people who are easily infected. | Breaking any one of the three links makes it hard for the germ to keep spreading. |
| 5 | Enough people are protected that the germ spreads only with difficulty. | When most people are vaccinated, the germ finds fewer people it can infect. |
| 6 | So that no germs are left behind to become resistant. | Symptoms may improve before the germs are gone, and stopping early lets the stronger ones survive. |
| 7 | 1120 seconds, that is 18.7 minutes | Twenty times eight times seven gives 1120 seconds, and dividing by sixty gives 18.7 minutes. |
| 8 | 18 people | Thirty times 0.6 gives 18, so turn the percentage into a decimal and multiply by the total. |
| 9 | 125 times | Two hundred and fifty divided by two gives 125, and the answer is a whole number of times. |
| 10 | Colds are mostly caused by viruses, and antibiotics work only on bacteria. | Error to fix: the wrong antibiotic does nothing and raises the chance of resistant bacteria appearing. |
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.
Paper four clears the conductor, insulator and battery direction misconceptions.Tutor 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.