Convection Quiz
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5 questions, one answer each
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1. In which states of matter can convection occur?
- A. A. Solids only
- B. B. Liquids and gases only
- C. C. Solids and liquids only
- D. D. All three states equally
2. What causes heated fluid to rise during convection?
- A. A. It becomes more dense than the surrounding fluid
- B. B. It becomes less dense than the surrounding fluid
- C. C. It gains extra mass when heated
- D. D. It is pushed up by cooler fluid from above
3. In the potassium permanganate experiment, what shows that a convection current is occurring?
- A. A. The water turns completely clear
- B. B. A visible purple trail rises from the heated crystal through the water
- C. C. The crystal sinks to the very bottom and stays still
- D. D. Bubbles form only at the surface of the water
4. Explain why a room heater is usually positioned near the floor rather than near the ceiling.
- A. A. So warmed air near the heater rises and sets up a convection current that circulates heat through the room
- B. B. Because heaters near the ceiling would conduct heat too slowly
- C. C. Because cool air always rises regardless of heater position
- D. D. Position makes no difference to how a room heats up
5. A car radiator cools engine coolant using both conduction and convection. Which statement correctly describes the roles of each process?
- A. A. Conduction carries heat through the air; convection carries heat through the metal fins
- B. B. Conduction carries heat through the metal fins to their surface; convection carries the heat away via rising warmed air around the fins
- C. C. Only convection is involved, as metals cannot conduct heat
- D. D. Only conduction is involved, as air cannot convect heat