CLAT– Geography

Vocabulary flashcards covering major geographical, environmental and Indian physical geography concepts from the lecture.

Universe

The totality of all space, time, matter and energy, from the tiniest sub-atomic particle to the largest structure.

Solar System

The Sun and all celestial bodies gravitationally bound to it, including 8 planets, dwarf planets, satellites, asteroids, meteors and comets.

Inner Planets

The four rocky planets—Mercury, Venus, Earth, Mars—located closest to the Sun.

Outer Planets

The four gas/ice giants—Jupiter, Saturn, Uranus, Neptune—located beyond the asteroid belt.

Celestial Body

Any natural object in space such as a star, planet, moon, asteroid, comet or meteor.

Astronomy

The scientific study of celestial bodies and phenomena outside Earth’s atmosphere.

Cosmology

The branch of astronomy that studies the origin, structure and evolution of the Universe.

Big Bang Theory

The prevailing explanation that the Universe began from an extremely hot, dense state ~13.8 billion years ago and has been expanding since.

Galaxy

A massive gravitational system of stars, gas, dust and dark matter; billions exist in the Universe.

Milky Way Galaxy

The spiral-shaped galaxy that contains our Solar System; called Aakash Ganga in India.

Constellation

A recognised group of stars forming an apparent pattern; 88 are officially recognised.

Star

A self-luminous sphere of hot gases generating energy via nuclear fusion.

Sirius

The brightest star visible from Earth’s night sky; nicknamed the Dog Star.

Proxima Centauri

The closest known star to the Solar System, located about 4.24 light-years away.

Rotation (Earth)

Earth’s spin on its axis, taking ~23 h 56 m 4 s relative to the stars and causing day and night.

Revolution (Earth)

Earth’s elliptical orbit around the Sun, completed in about 365 days, producing seasons.

Perihelion

The point in Earth’s orbit when it is nearest the Sun (about 3 January).

Aphelion

The point in Earth’s orbit when it is farthest from the Sun (about 4 July).

Apogee

Position where the Moon is farthest from Earth in its orbit (~417 000 km).

Perigee

Position where the Moon is closest to Earth in its orbit.

Solar Eclipse

Occurs when the Moon passes between Sun and Earth, casting a shadow on Earth’s surface (new-moon day).

Lunar Eclipse

Occurs when Earth comes between Sun and Moon, casting Earth’s shadow on the Moon (full-moon day).

Blue Moon

The second full moon occurring within a single calendar month, roughly every 3 years.

Latitude

Imaginary horizontal line on a globe, measured in degrees north or south of the Equator.

Longitude

Imaginary vertical line on a globe, measured in degrees east or west of the Prime Meridian.

Equator

The 0° latitude circle dividing Earth into Northern and Southern Hemispheres.

Tropic of Cancer

The parallel at 23½° N latitude marking the northern limit of direct overhead Sun.

Tropic of Capricorn

The parallel at 23½° S latitude marking the southern limit of direct overhead Sun.

Arctic Circle

Latitude 66½° N; north of it receives at least one 24-hour day/night annually.

Antarctic Circle

Latitude 66½° S; south of it receives at least one 24-hour day/night annually.

Prime Meridian

0° longitude passing through Greenwich, England; reference for GMT.

International Date Line

180° meridian where the calendar date changes by one day when crossed.

Indian Standard Time (IST)

Time based on 82°30′ E longitude; 5 h 30 m ahead of GMT.

Crust

Earth’s outermost solid layer, 8–40 km thick, composed mainly of Sial.

Mantle

Layer beneath the crust extending to ~2900 km, composed largely of Sima.

Core

Earth’s innermost layer (2900–6370 km) composed chiefly of nickel-iron (Nife).

Sial

Upper crustal layer rich in silica and aluminium.

Sima

Lower crust/mantle material rich in silica and magnesium.

Nife

Nickel-iron composition of Earth’s core.

Igneous Rock

‘Primary’ rock formed by cooling and solidification of magma; e.g., granite.

Sedimentary Rock

Rock formed from deposition and compaction of sediments; e.g., limestone.

Metamorphic Rock

Rock altered by heat and pressure from pre-existing rock; e.g., marble.

Petrology

Scientific study of rocks, their origin, structure and composition.

Atmosphere

Envelope of gases surrounding Earth, retained by gravity, essential for life.

Troposphere

Lowest atmospheric layer (0–8/18 km) containing ~90 % of air and weather events.

Stratosphere

Layer from ~18 km to 50 km containing the ozone layer; temperature rises with height.

Mesosphere

50–80 km layer; coldest part of atmosphere (~–90 °C).

Ionosphere

80–400 km layer rich in ions; reflects radio waves for communication.

Exosphere

Outermost atmospheric layer merging into space; extremely thin.

Endogenic Forces

Internal Earth forces such as volcanism and tectonics shaping the crust.

Exogenic Forces

External forces like weathering, erosion and deposition modifying the surface.

Earthquake

Sudden shaking of Earth’s crust due to rapid energy release along faults.

Focus (Hypocentre)

Point within Earth where an earthquake originates.

Epicentre

Point on Earth’s surface directly above the focus of an earthquake.

Richter Scale

Logarithmic scale (0–9) measuring magnitude of seismic energy released.

Mercalli Scale

Qualitative scale measuring earthquake intensity based on observed effects.

Seismology

Scientific study of earthquakes and seismic waves.

Volcano

Surface opening through which magma, gases and ash erupt; process called volcanism.

Active Volcano

Volcano that erupts frequently or shows current activity.

Dormant Volcano

Currently quiet volcano expected to erupt again.

Extinct Volcano

Volcano not expected to erupt again.

Pacific Ring of Fire

Zone encircling the Pacific with ~68 % of the world’s volcanoes and many earthquakes.

Landform

Recognisable natural feature of Earth’s surface, e.g., mountain, plateau, desert.

Continent

Large continuous landmass; Earth has seven (Asia, Africa, N. America, S. America, Antarctica, Europe, Australia).

Fold Mountain

Mountain formed by compression and folding of crustal rocks, e.g., Himalayas.

Block Mountain

Mountain formed by uplift of crustal blocks along faults, e.g., Sierra Nevada.

Volcanic Mountain

Mountain built by successive volcanic eruptions, e.g., Mount Fuji.

Relict Mountain

Eroded remnant of ancient mountains, e.g., Aravalli Range.

Plateau

Elevated flat-topped area rising at least 500 ft above surroundings.

Desert

Region receiving very low annual rainfall (<250 mm); can be hot or cold.

Grassland

Wide plain dominated by grasses; names vary by region (prairie, savanna, etc.).

Hydrosphere

All water on Earth’s surface, underground and in the atmosphere (~70 % of surface).

Pacific Ocean

Largest and deepest ocean; site of Mariana Trench.

Atlantic Ocean

S-shaped second-largest ocean, busiest for trade; longest coastline.

Indian Ocean

Only ocean named after a country; second deepest, houses Sunda Trench.

Arctic Ocean

Smallest, shallowest and least saline ocean.

Mariana Trench

World’s deepest oceanic trench (~11 034 m) in the Pacific.

Lake Baikal

World’s deepest freshwater lake (1637 m) in Siberia.

Lake Tanganyika

World’s longest freshwater lake (660 km) and second deepest.

Strait

Narrow water passage connecting two larger water bodies; e.g., Bering Strait.

Canal

Man-made waterway linking two water bodies; e.g., Suez Canal.

Ocean Current

Large, persistent horizontal flow of ocean water driven by wind, density and Coriolis force.

Spring Tide

Highest tide occurring at full and new moons when Sun, Moon and Earth align.

Neap Tide

Lowest tide occurring at first and third quarter moons when Sun and Moon are at right angles to Earth.

Cyclone

Large-scale low-pressure system with spiral winds; called hurricanes or typhoons regionally.

Hurricane

Tropical cyclone in the North Atlantic & eastern Pacific.

Typhoon

Tropical cyclone in the western Pacific & East Asia.

Willy-Willy

Term for tropical cyclone in Australia.

Monsoon

Seasonal reversing wind system bringing wet (SW) and dry (NE) seasons to South Asia.

Himalayas

Young fold mountain range stretching ~2400 km, forming India’s northern barrier.

Northern Plains

Extensive alluvial plain south of Himalayas, formed by Indus, Ganga and Brahmaputra.

Peninsular Plateau

Old crystalline tableland covering Deccan and Central Highlands of India.

Western Ghats

Mountain chain along India’s west coast, ecological hotspot, meets Eastern Ghats at Nilgiri.

Indian Desert (Thar)

Arid region in NW India mainly in Rajasthan; bordered east by Aravalli Range.

Alluvial Soil

Fertile, fine soil deposited by rivers; dominant in Indo-Gangetic plains.

Black Soil (Regur)

Clayey, dark soil rich in calcium & suitable for cotton; found in Deccan Trap.

Red Soil

Iron-rich, reddish soil formed from crystalline rocks in drier parts of Deccan.

Laterite Soil

Leached, iron-aluminium-rich soil in high rainfall areas; supports tea, coffee, rubber.

Kharif Crops

Monsoon-sown crops (June–Oct) like rice, maize, cotton.

Rabi Crops

Winter-sown crops (Oct–March) like wheat, barley, mustard.