Secondary 4 Geography Physical Geography Quiz

Answer Key - Secondary 4 Geography Quiz (Physical Geography)

Section A: Weather and Climate

1. Weather: Short-term state of the atmosphere at a specific place and time (e.g., rainy today). Climate: Long-term average of weather patterns over a period (usually 30 years). (2m)
2. Rotation causes different parts of the Earth to face the sun at different times. This creates the day-night cycle, leading to diurnal temperature variation (heating during day, cooling at night). (3m)
3. Solar radiation heats the ground $\rightarrow$ air above warms and rises $\rightarrow$ air cools as it ascends $\rightarrow$ water vapor condenses into clouds $\rightarrow$ heavy rain falls. (4m)
4. High angle of incidence of solar radiation; the sun's rays are concentrated over a smaller area, providing more intense heat. (3m)
5. Rainforest: High temp and high rainfall year-round, minimal seasonal variation. Monsoon: High temp year-round, but distinct wet and dry seasons driven by seasonal wind shifts. (4m)
6. Temperature decreases with increasing altitude (lapse rate). Air becomes less dense at higher altitudes, holding less heat. (3m)
7. ITCZ is a low-pressure zone where trade winds converge $\rightarrow$ forces air to rise $\rightarrow$ leads to frequent convectional rainfall and thunderstorms. (4m)

Section B: Climate Change

8. Definition: Long-term shift in global or regional climate patterns. Indicator: Rising global mean temperatures / rising sea levels. (2m)
9. Eruptions release aerosols (sulfur dioxide) into the stratosphere $\rightarrow$ these reflect incoming solar radiation back into space $\rightarrow$ less heat reaches the surface. (3m)
10. Effect: Greenhouse gases (CO2, CH4) trap long-wave radiation emitted from Earth's surface, warming the atmosphere. Activity: Burning of fossil fuels / Deforestation. (4m)
11. Ice has high albedo (reflects sunlight). Melting ice exposes darker ocean/land $\rightarrow$ absorbs more heat $\rightarrow$ increases temperature $\rightarrow$ causes more ice to melt. (4m)
12. Example: Increased temperatures expand the habitat of disease vectors (e.g., mosquitoes), leading to a higher prevalence of diseases like Dengue or Malaria. (3m)
13. Mitigation: Addressing the cause (e.g., switching to solar energy to reduce CO2). Adaptation: Adjusting to the effect (e.g., building sea walls to prevent flooding). (4m)

Section C: Tectonics and Hazards

14. Crust: Thin, rocky outer shell. Mantle: Semi-molten asthenosphere. Core: Dense center (outer liquid, inner solid). (3m)
15. Heat from the core creates currents in the mantle $\rightarrow$ hot magma rises, cools, and sinks $\rightarrow$ this "conveyor belt" motion drags the overlying tectonic plates. (4m)
16. Divergent: Mid-ocean ridges, rift valleys (plates move apart). Convergent: Fold mountains, ocean trenches, volcanic arcs (plates collide). (4m)
17. Plate boundaries are sites of intense friction and pressure buildup (stress). When this stress is released suddenly, it causes an earthquake. (3m)
18. Hazard (magnitude) is constant. However, a country with high Vulnerability (poor building codes, high population density) and low Capacity (poor emergency services, lack of education) will have higher risk/casualties. (5m)
19. Primary: Lava flows, pyroclastic flows, ash fall. Secondary: Lahars (mudflows), tsunamis (if eruption is undersea), climate cooling (ash blocking sun). (4m)
20. Effectiveness: Highly effective in reducing structural collapse and saving lives (e.g., Japan). Limitations: High cost of implementation, difficulty in retrofitting old buildings, does not prevent non-structural damage or panic. (6m)