This is an original, chapter-wise study digest of the NCERT Class XI textbook Fundamentals of Physical Geography. It paraphrases the syllabus content in compact form for CAPF revision and does not reproduce the book's text. Read the full NCERT once, then use this to revise. The booklist context is in booklist and the source policy is in sources index.
CAPF tests physical geography mainly as clean static facts and clear mechanisms (why the monsoon reverses, why fold mountains form, why western coasts of continents are wet in the temperate belt). Memorise the definitions and the cause-effect chains.
- Geography studies the spatial variation of physical and human phenomena and their interrelation. Physical geography deals with the natural environment; human geography deals with people and their activities.
- Branches relevant to CAPF: geomorphology (landforms), climatology (atmosphere and weather), hydrology (water), oceanography (oceans), and biogeography (life).
- Two approaches: systematic (study one element worldwide) and regional (study all elements in one region).
- Big Bang theory: the universe began about 13.7 billion years ago from a singularity that expanded; galaxies formed from gas clouds. Edwin Hubble's observation that galaxies are receding supports an expanding universe.
- Nebular hypothesis (Laplace, refined later): the Sun and planets condensed from a rotating disc of gas and dust about 4.6 billion years ago.
- Earth's evolution: a hot molten body cooled; heavier material (iron, nickel) sank to form the core, lighter material rose to form the crust (differentiation). Degassing released water vapour and gases that formed the early atmosphere and oceans.
- Moon: most accepted view is the giant impact ("Big Splat"), a Mars-sized body striking the early Earth.
- Sources of information: direct (mining, drilling, volcanic material) and indirect (density, gravity, magnetism, meteorites, and crucially seismic waves).
- Earthquake waves: body waves (P and S) travel through the interior; surface waves (L) travel along the surface and cause most destruction.
- P-waves (primary, longitudinal) are fastest and pass through solids, liquids and gases.
- S-waves (secondary, transverse) pass only through solids; their failure to pass through the outer core proves the outer core is liquid.
- Shadow zones: P-wave shadow zone roughly 105 to 145° from the epicentre; S-wave shadow zone beyond 105° (a wider zone), confirming the liquid outer core.
- Layered structure: crust (thin; continental SIAL, oceanic SIMA), mantle (Mohorovicic discontinuity separates crust and mantle), outer core (liquid) and inner core (solid iron-nickel, NIFE).
See geomorphology earth interior and plate tectonics for the exam-level treatment.
- Continental Drift (Alfred Wegener, 1912): a single supercontinent Pangaea, surrounded by Panthalassa, split into Laurasia (north) and Gondwanaland (south). Evidence: jigsaw fit of coasts, matching rocks and fossils across oceans, placer deposits, and tillite (glacial) beds.
- Sea-floor spreading (Harry Hess): new oceanic crust forms at mid-oceanic ridges and moves outward; supported by palaeomagnetism (symmetrical magnetic stripes either side of ridges) and the youth of oceanic crust.
- Plate tectonics: the lithosphere is broken into seven major and several minor plates that move over the asthenosphere. Three boundary types:
- Divergent (constructive): plates move apart; new crust forms (mid-Atlantic ridge).
- Convergent (destructive): plates collide; subduction or mountain-building (Himalayas from the Indo-Australian and Eurasian collision).
- Transform (conservative): plates slide past each other (San Andreas Fault).
- The driving force is mantle convection currents.
- Mineral: a naturally occurring inorganic substance with a definite chemical composition. Rocks are aggregates of minerals.
- Three rock types:
- Igneous (formed from cooling magma/lava; intrusive like granite, extrusive like basalt). The original "primary" rocks.
- Sedimentary (deposition and compaction of sediments; in layers/strata; sandstone, limestone, shale). May contain fossils.
- Metamorphic (existing rocks changed by heat/pressure; limestone to marble, sandstone to quartzite, coal to graphite, shale to slate).
- The rock cycle: rocks transform from one type to another over geological time.
- Endogenic (internal) forces: diastrophism (folding, faulting, plate movement) and volcanism; build relief.
- Exogenic (external) forces: weathering, erosion, transport and deposition by water, wind, ice and waves; wear down relief (denudation).
- Weathering: mechanical (physical breakup, for example frost action, exfoliation), chemical (solution, oxidation, carbonation), and biological. Weathering prepares material for erosion and forms soil.
- Mass movement: slow (creep, solifluction) to rapid (landslides, slumps).
- Running water (most important in humid regions): forms valleys, gorges, waterfalls, meanders, ox-bow lakes, flood plains, deltas, alluvial fans.
- Groundwater (karst topography in limestone): sinkholes, caves, stalactites and stalagmites.
- Glaciers: U-shaped valleys, cirques, moraines, fjords.
- Wind (arid regions): mushroom rocks, deflation hollows, sand dunes, loess.
- Waves and currents (coasts): cliffs, sea caves, beaches, spits, bars.
- Composition: nitrogen (about 78 percent), oxygen (about 21 percent), argon, carbon dioxide and trace gases, plus water vapour and dust.
- Layers by height: troposphere (weather occurs here; temperature falls with height), stratosphere (contains the ozone layer; temperature rises with height), mesosphere (coldest; meteors burn), thermosphere/ionosphere (reflects radio waves; aurora), exosphere.
- Normal lapse rate: temperature falls about 6.5° Celsius per 1000 metres in the troposphere.
See climatology atmosphere and winds.
- Insolation: incoming solar radiation. The Earth receives only a tiny fraction of the Sun's output. The atmosphere is mainly heated from below by terrestrial (long-wave) radiation.
- Heat budget: incoming and outgoing radiation balance over the year, keeping global temperature stable. The greenhouse effect traps long-wave radiation and warms the surface.
- Temperature controls: latitude, altitude, distance from the sea (continentality), ocean currents, prevailing winds, cloud cover and aspect.
- Inversion of temperature: temperature rises with height (reverses the normal pattern), common on clear, calm winter nights in valleys.
- Air pressure falls with height. Pressure belts: equatorial low, subtropical high, subpolar low, polar high.
- Planetary winds (Coriolis force deflects them, right in the Northern Hemisphere): trade winds, westerlies, polar easterlies.
- Cyclones: tropical cyclones (warm-core, over warm tropical seas, very destructive) and temperate (mid-latitude, frontal) cyclones. An anticyclone has high pressure at the centre with diverging winds.
- Air masses and fronts: warm front, cold front, occluded front and stationary front.
- Humidity: absolute (actual water vapour per volume) and relative (percent of saturation). Dew point is the temperature at which air becomes saturated.
- Condensation forms: dew, frost, fog, mist and clouds (cirrus, cumulus, stratus, nimbus and combinations).
- Precipitation types by cause: convectional (heating, equatorial), orographic (relief; windward wet, leeward dry rain-shadow) and cyclonic/frontal.
- Koppen classification uses temperature and rainfall to define climate groups (A tropical, B dry, C warm temperate, D cold, E polar, plus H highland).
- Greenhouse gases (carbon dioxide, methane, nitrous oxide, CFCs) intensify warming. Global warming raises sea levels and shifts climate zones.
- Past climate is read from tree rings, ice cores, pollen and sediments.
- The hydrological cycle moves water between ocean, atmosphere and land. Oceans hold about 97 percent of Earth's water.
- Ocean relief: continental shelf (rich fishing grounds), continental slope, deep-sea plain (abyssal), mid-oceanic ridges, trenches (Mariana Trench is the deepest point).
- See oceanography for currents, tides and salinity.
- Waves (wind energy), tides (gravitational pull of the Moon and Sun; spring tides at new and full moon, neap tides at quarters) and currents (warm and cold; influence coastal climate and fisheries, for example the Gulf Stream warming Western Europe).
- Salinity averages about 35 parts per thousand; highest in enclosed warm seas with high evaporation.
- The biosphere is the zone where land, air and water support life. An ecosystem links living organisms (biotic) and the non-living environment (abiotic) through energy flow and nutrient cycling.
- Food chains, food webs and trophic levels: energy decreases at each higher level (the 10 percent rule).
- Biodiversity: genetic, species and ecosystem diversity. Loss is driven by habitat destruction, over-exploitation, pollution and invasive species.
- Conservation: protected areas (national parks, sanctuaries, biosphere reserves), the Convention on Biological Diversity, and the IUCN Red List (which classifies species as vulnerable, endangered, critically endangered).
- Direct one-liners: order of atmospheric layers, deepest ocean trench, which seismic wave proves the liquid core, rock type of marble.
- Mechanism statements: orographic rainfall and rain shadow, Coriolis deflection direction, why oceanic crust is young.
- Match the following: rock to type, landform to agent, plate boundary to example.
- Which seismic wave does not travel through liquids, thereby proving the outer core is liquid? (Answer: S-wave / secondary wave.) Authored practice, not a verbatim PYQ.
- The collision of which two plates raised the Himalayas? (Answer: Indo-Australian and Eurasian plates.) Authored practice, not a verbatim PYQ.