Exam Hints of The Way Science Works 103-2

1. Why is steel tougher than iron ?

2. What is the major weakness of cement as a construction material ?

3. Sewage water treatment can have primary and advanced treatments, what are the the things to be treated respectively.

4. Why is it not a good idea to raise livestock and poultry in the water collection area of a dam?

5. What is Brownian Motion ? What has this to do with precipitation of dust in water ?

6. Why must alum (Aluminium Sulphate) be added in the purification processes? What is the purpose of adding chlorine to tap water??

7. In which way phosphorus-free washing powder is better than a non phosphorus-free one ?

8. Why electrical power company convert the voltage output of generators into ultra high-voltage electricity for distribution?

9. Why large-size air conditioners and electric baking ovens use 220V power instead of 110V ?

10. At absolute zero temperature, what is happening at microscopic level ?

11. Explain "resonance", and give two examples.

12. A popular type of refrigerant used in the past was ammonia (NH3), what are the shortcomings of using this material ?

13. Explain how dehumidifiers work.

14. How temperature control in a refrigerator is achieved ?