Physical Geography
Landforms, Atmosphere, Hydrosphere and Biosphere
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Overview
Physical Geography examines the natural environment of Earth—its landforms, air, water, and living systems. For TN TET Paper II Social Studies, this topic forms the foundation for understanding India's and Tamil Nadu's physical features, climate patterns, and resource distribution. Questions typically test your knowledge of how landforms are created, layers of the atmosphere, the water cycle, and ecological relationships.
Mastery here requires understanding processes (how mountains form, why winds blow, how water cycles) rather than just memorising definitions. Expect 3–5 questions combining factual recall with application—such as identifying the atmospheric layer where weather occurs or explaining why deltas form at river mouths.
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Key Concepts
- **Lithosphere** is Earth's solid outer shell comprising the crust and upper mantle; it includes all landforms—mountains, plateaus, and plains.
- **Endogenic forces** (internal—volcanism, earthquakes, folding, faulting) create primary landforms; **exogenic forces** (external—weathering, erosion, deposition) modify them into secondary landforms.
- **Atmosphere** is the gaseous envelope surrounding Earth, held by gravity, essential for life, weather, and climate regulation.
- **Hydrosphere** includes all water on Earth—oceans (97.5%), ice caps, groundwater, rivers, and atmospheric moisture; only about 2.5% is freshwater.
- **Biosphere** is the zone of life where atmosphere, hydrosphere, and lithosphere interact; it extends from ocean depths to about 10 km above sea level.
- **Water cycle** (hydrological cycle) describes continuous movement of water through evaporation, condensation, precipitation, and collection.
- **Ecosystem** is a functional unit where biotic (living) and abiotic (non-living) components interact through energy flow and nutrient cycling.
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Formulas / Key Facts
### Landforms
| Landform | Formation Process | Indian Example | |----------|-------------------|----------------| | Fold Mountains | Compression of tectonic plates | Himalayas | | Block Mountains | Faulting and uplift | Satpura, Vindhya | | Volcanic Mountains | Accumulation of lava/ash | Barren Island (Andaman) | | Plateaus | Uplift or lava accumulation | Deccan Plateau, Chotanagpur | | Plains | Deposition by rivers | Indo-Gangetic Plain | | Deltas | River sediment deposition at mouth | Sundarbans, Kaveri Delta | | V-shaped valleys | River erosion in upper course | Himalayan river valleys |