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275 UPSC previous-year questions in Physical Geography, with answers and concise explanations, grouped by topic. Showing the 120 most recent — open a topic for the rest.
Read the Physical Geography notesConsider the following pairs: Region – Country I. Mallorca : Italy II. Normandy : Spain III. Sardinia : France In how many of the above rows is the given information correctly matched?
Why
Mallorca belongs to Spain, Normandy is a region of France, and Sardinia is an island of Italy, all three pairs are incorrectly matched.
Consider the following water bodies: I. Lake Tanganyika II. Lake Tonlé Sap III. Patos Lagoon Through how many of them does the equator pass?
Why
The equator passes through none of these, Lake Tanganyika is south of the equator, Tonlé Sap is in Cambodia (north of equator but far from it), and Patos Lagoon is in southern Brazil.
Consider the following countries: I. United Kingdom II. Denmark III. New Zealand IV. Australia V. Brazil How many of the above countries have more than four time zones?
Why
France (via overseas territories), Russia, and the USA each have more than four time zones; among the listed countries, New Zealand, Australia, and Brazil qualify.
Consider the following information: Region – Name of the mountain range – Type of Mountain
In how many of the above rows is the given information correctly matched?
Why
Only rows 3 and 4 are correct: Appalachians (North America) and Andes (South America) are fold mountains; Vosges is in Europe (not Central Asia) and is a block mountain, while the Alps are fold mountains (not block mountains).
The longest border between any two countries in the world is between:
Why
The Canada–USA border stretches approximately 8,891 km, making it the longest international land border in the world.
Consider the following statements:
Which of the statements given above is/are correct?
Why
The Red Sea is in an extremely arid zone with negligible rainfall, and no major rivers drain into it, making both statements correct.
Consider the following countries:
How many of the above countries have a border with the North Sea?
Why
Only Norway and Germany border the North Sea; Finland borders the Baltic Sea and Russia does not touch the North Sea.
Consider the following countries:
How many of the above-mentioned countries share a land border with Ukraine?
Why
Among the listed countries only Hungary and Romania share a land border with Ukraine; Bulgaria, Czech Republic, Latvia, and Lithuania do not.
Consider the following countries:
Which of the above have borders with Afghanistan?
Why
Tajikistan, Turkmenistan, and Uzbekistan share borders with Afghanistan; Azerbaijan and Kyrgyzstan do not.
Consider the following pairs: River — Flows into
Which of the pairs given above is/are correctly matched?
Why
The Volga flows into the Caspian Sea and the Zambezi drains into the Indian Ocean (Mozambique Channel); the Mekong flows into the South China Sea and the Thames into the North Sea.
Consider the following pairs: Sea — Bordering Country
Which of the pairs given above are correctly matched?
Why
Albania borders the Adriatic Sea, Kazakhstan borders the Caspian Sea, and Morocco borders the Mediterranean Sea; Croatia does not border the Black Sea and Syria does not border the Red Sea.
Consider the following pairs: Regions sometimes mentioned in the news – Country
Which of the pairs given above are correctly matched?
Why
Catalonia is a region of Spain and Mindanao is an island in the Philippines; Crimea is a Ukrainian peninsula (not Hungary) and Oromia is a region in Ethiopia (not Nigeria).
Which of the following has/have shrunk immensely/dried up in the recent past due to human activities?
Select the correct answer using the code given below:
Why
The Aral Sea in Central Asia has drastically shrunk due to diversion of its feeder rivers for irrigation; the Black Sea and Lake Baikal have not dried up.
Mediterranean Sea is a border of which of the following countries?
Select the correct answer using the code given below:
Why
Lebanon and Syria have coastlines on the Mediterranean Sea; Jordan is landlocked except for a small Red Sea coast, and Iraq has no Mediterranean coast.
Which one of the following countries of South-West Asia does not open out to the Mediterranean Sea?
Why
Jordan is essentially landlocked with only a small outlet to the Red Sea at Aqaba and does not border the Mediterranean Sea.
What is the correct sequence of occurrence of the following cities in South-East Asia as one proceeds from south to north?
Select the correct answer using the code given below:
Why
Going south to north: Jakarta (Indonesia) is furthest south, then Singapore, then Bangkok (Thailand), then Hanoi (Vietnam), giving the sequence 3-4-1-2.
Turkey is located between:
Why
Turkey sits between the Black Sea to the north and the Mediterranean Sea (via the Aegean) to the south/west.
Which of the following pairs is correctly matched?
Why
The Atlas Mountains run along the north-western coast of Africa through Morocco, Algeria, and Tunisia; the other pairings are all geographically incorrect.
Between India and east Asia, the navigation-time and distance can be greatly reduced by which of the following?
Which of the statements given above is/are correct?
Why
A canal through the Kra Isthmus would create a shortcut bypassing the Malacca Strait and significantly reduce navigation time; merely deepening the Malacca Strait would not shorten distance.
With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements: I. All types of UAVs can do vertical landing. II. All types of UAVs can do automated hovering. III. All types of UAVs can use battery only as a source of power supply. How many of the statements given above are correct?
Why
None of the statements are correct, not all UAVs can do vertical landing, automated hovering, or run solely on battery power.
Consider the following space missions: I. Axiom-4 II. SpaDeX III. Gaganyaan How many of the space missions given above encourage and support micro-gravity research?
Why
All three missions, Axiom-4 (commercial ISS mission), SpaDeX (space docking experiment), and Gaganyaan (India's human spaceflight), involve micro-gravity research as part of their objectives.
Consider the following statements: Statement I: Giant stars live much longer than dwarf stars. Statement-II: Compared to dwarf stars, giant stars have greater rate of nuclear reactions. Which one of the following is correct in respect of the above statements?
Why
Giant stars burn through their fuel much faster due to higher nuclear reaction rates and therefore have shorter lifespans than dwarf stars, making Statement I false and Statement II true.
Consider the following pairs: Objects in space — Description
How many of the above pairs are correctly matched?
Why
Only Pulsars are correctly described; Cepheids are variable stars (not dust clouds) and Nebulae are clouds of gas and dust (not periodically brightening stars), so only pair 3 is correct.
Which one of the following countries has its own Satellite Navigation System?
Why
Japan operates QZSS (Quasi-Zenith Satellite System), its own regional satellite navigation system, whereas Australia, Canada, and Israel do not have independent navigation satellite systems.
Which one of the following statements best reflects the idea behind the "Fractional Orbital Bombardment System" often talked about in the media?
Why
The Fractional Orbital Bombardment System places a nuclear warhead into low Earth orbit and deorbits it over a target, bypassing traditional missile defence systems.
If a major solar storm (solar-flare) reaches the Earth, which of the following are the possible effects on the Earth?
Select the correct answer using the code given below:
Why
Solar storms can disrupt GPS, damage power grids, cause auroras, disturb satellite orbits, and interrupt polar radio communication, but they do not directly cause tsunamis or forest fires.
Which one of the following is a reason why astronomical distances are measured in light-years?
Why
The light-year is a reliable unit for astronomical distances because the speed of light in a vacuum is constant (~3×10⁸ m/s), making it a universal standard of measurement.
"The experiment will employ a trio of spacecraft flying in formation in the shape of an equilateral triangle that has sides one million kilometres long, with lasers shining between the craft." The experiment in question refers to:
Why
The description matches the eLISA (Evolved Laser Interferometer Space Antenna) mission, designed to detect gravitational waves using a triangular formation of spacecraft with laser interferometry.
Recently, scientists observed the merger of giant black holes billions of light-years away from the Earth. What is the significance of this observation?
Why
The merger of giant black holes generates gravitational waves, and the LIGO/Virgo observatories detected these ripples in space-time, confirming a key prediction of Einstein's general relativity.
For the measurement/estimation of which of the following are satellite images/remote sensing data used?
Select the correct answer using the code given below.
Why
Remote sensing satellites can measure chlorophyll content via spectral reflectance, greenhouse gas emissions via infrared sensors, and land surface temperatures via thermal imaging, all three are valid applications.
Consider the following statements:
Which of the statements given above is/are correct?
Why
Earth's magnetic field has reversed periodically (statement 1 correct), early Earth had little free oxygen and lots of CO₂/methane (statement 2 incorrect), and early life transformed the atmosphere by producing oxygen (statement 3 correct).
In which of the following areas can GPS technology be used?
Which of the above is/are correct?
Why
GPS is used in mobile phones for navigation, in banking for time-stamping transactions, and in power grid synchronisation, making all three applications valid.
Consider the following phenomena:
Which of the above is/are prediction/predictions of Albert Einstein's General Theory of Relativity, often discussed in media?
Why
Einstein's General Theory of Relativity predicts gravitational lensing of light, the expanding universe (via Friedmann equations applied to GR), and the curvature of space-time by mass, all three are correct predictions.
With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements:
Which of the following statements given above is/are correct?
Why
IRNSS (NavIC) has 3 geostationary and 4 geosynchronous satellites (statement 1 correct); it covers India and ~1500 km beyond (not 5500 km) and provides regional not global coverage, making statements 2 and 3 incorrect.
With reference to India's satellite launch vehicles, consider the following statements:
Which of the statements given below is/are correct?
Why
Statement 1 is correct, PSLV launches remote sensing satellites and GSLV launches heavier communication satellites; PSLV satellites are in polar/sun-synchronous orbits (not geostationary), and GSLV Mk III uses a different staging configuration, making statements 2 and 3 incorrect.
What is the purpose of 'evolved Laser Interferometer Space Antenna (eLISA)' project?
Why
eLISA is a planned ESA space mission designed to detect gravitational waves, ripples in space-time, using laser interferometry across spacecraft separated by millions of kilometres.
The terms 'Event Horizon', 'Singularity', 'String Theory' and 'Standard Model' are sometimes seen in the news in the context of:
Why
All four terms, event horizon, singularity, string theory, and the standard model, are concepts from theoretical physics used in the observation and understanding of the universe.
What is 'Greased Lightning-10 (GL-10)', recently in the news?
Why
GL-10 Greased Lightning is a battery-powered, remotely piloted aircraft tested by NASA that can take off and land vertically like a helicopter and fly efficiently like a plane.
With reference to 'Astrosat', the astronomical observatory launched by India, which of the following statements is/are correct?
Select the correct answer using the code given below.
Why
Astrosat is India's first multi-wavelength space observatory, but statement 1 is wrong as other countries (e.g., ESA) also have such observatories, and statement 2 is wrong as Astrosat is ~1513 kg in a ~650 km orbit.
Consider the following statements: The Mangalyaan launched by ISRO
Which of the statements given above is/are correct?
Why
Mangalyaan is indeed the Mars Orbiter Mission (statement 1 correct) and India was the first to succeed on its maiden attempt (statement 3 correct), but India was the fourth space agency to reach Mars orbit (not the second), making statement 2 incorrect.
The term 'Goldilocks Zone' is often seen in the news in the context of:
Why
The Goldilocks Zone (circumstellar habitable zone) refers to the range of distances from a star where conditions are neither too hot nor too cold for liquid water and life, used in the search for Earth-like exoplanets.
In which of the following activities are Indian Remote Sensing (IRS) satellites used?
Select the correct answer using the code given below
Why
IRS satellites are used for Earth observation activities like crop assessment, groundwater location, and mineral exploration, but not for telecommunications (that is INSAT's role) or traffic monitoring.
Which of the following pairs is/are correctly matched? Spacecraft — Purpose:
Select the correct answer using the code given below.
Why
Cassini-Huygens orbited Saturn (not Venus), so pair 1 is wrong; Messenger mapped Mercury, and Voyager 1 and 2 explored the outer solar system, so only pairs 2 and 3 are correctly matched.
Electrically charged particles from space travelling at speeds of several hundred km/sec can severely harm living beings if they reach the surface of the Earth. What prevents them from reaching the surface of the Earth?
Why
Earth's magnetosphere deflects charged solar wind particles toward the poles where they interact with the atmosphere to create auroras, preventing them from reaching populated regions.
Which of the following is/are cited by the scientists as evidence/evidences for the 'continued expansion of universe'?
Select the correct answer using the codes given below:
Why
The Cosmic Microwave Background (CMB) radiation and the redshift of distant galaxies are the two key evidences for the expanding universe; asteroid movement and supernovae are not direct evidence of universal expansion.
What is difference between asteroids and comets?
Which of the statements given above is/are correct?
Why
Statement 1 (composition difference) and statement 3 (comets have tails, asteroids don't) are correct; statement 2 is wrong as comets originate from the Kuiper Belt or Oort Cloud, not between Venus and Mercury.
An artificial satellite orbiting around the earth does not fall down. This is so because the attraction of earth:
Why
Earth's gravity acts as centripetal acceleration keeping the satellite in a curved orbit; since the satellite moves tangentially at orbital speed, this acceleration continuously changes its direction without pulling it down.
Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such an orbit when:
Which is the correct answer using the codes given below:
Why
A geostationary orbit requires the orbit to be geosynchronous, circular, and in the equatorial plane; the altitude ~35,786 km is a consequence, not a separate defining requirement, so options 1, 2, and 3 define it.
In the context of space technology, what is "Bhuvan", recently in the news?
Why
Bhuvan is ISRO's web-based geoportal that provides 3D satellite imagery of India similar to Google Earth, supporting GIS applications and spatial data visualisation.
Consider the following statements: Statement I: In January, in the Northern Hemisphere, the isotherms bend equatorward while crossing the landmasses, and poleward while crossing the oceans. Statement II: In January, the air over the oceans is warmer than that over the landmasses in the Northern Hemisphere. Which one of the following is correct in respect of the above statements?
Why
In January, oceans in the Northern Hemisphere are warmer than adjacent landmasses, causing isotherms to bend poleward over oceans, and this temperature contrast directly explains the isotherm deviation.
Which of the following is/are correct inference/inferences from isothermal maps in the month of January?
Select the answer using the code given below:
Why
In January, oceans are warmer than continents in the Northern Hemisphere, so isotherms bend northward (poleward) over oceans and southward (equatorward) over continents; Statement 2 is wrong because Gulf Stream and North Atlantic Drift are warm currents, not cold.
Consider the following statements:
Statement-I: The temperature contrast between continents and oceans is greater during summer than in winter.
Statement-II: The specific heat of water is more than that of land surface. Which one of the following is correct in respect of the above statements?
Why
The temperature contrast is actually greater in winter (not summer) because continents cool far more than oceans; however, Statement-II is correct since water has a much higher specific heat than land.
Consider the following statements: 1) In the tropical zone, the western sections of the oceans are warmer than the eastern sections owing to the influence of trade winds. 2) In the temperate zone, westerlies make the eastern sections of oceans warmer than the western sections. Which of the statements given above is/are correct?
Why
Trade winds push warm surface water westward in the tropics warming the western ocean margins, while westerlies carry warm water eastward in temperate latitudes making eastern ocean margins warmer.
With reference to Ocean Mean Temperature (OMT), which of the following statements is/are correct?
Select the correct answer using the code given below:
Why
OMT is measured up to the depth of the 26°C isotherm (not fixed at 129 m, which varies by region and season), but pre-monsoon OMT is a valid predictor of monsoon rainfall intensity.
The annual range of temperature in the interior of the continents is high as compared to coastal areas. What is/are the reason/reasons?
Select the correct answer using the codes given below.
Why
The primary reason for higher annual temperature range in continental interiors is the lower specific heat of land compared to water, which causes land to heat up and cool down more rapidly than the ocean.
Consider the following countries: I. Bolivia II. Brazil III. Colombia IV. Ecuador V. Paraguay VI. Venezuela Andes mountains pass through how many of the above countries?
Why
The Andes run through Colombia, Ecuador, Bolivia, and Venezuela (four countries); Bolivia, Brazil, Paraguay and Venezuela are partially correct but Brazil and Paraguay are not Andean countries, the four Andean nations among the list are Colombia, Ecuador, Bolivia, and Venezuela.
Consider the following statements: I. Anadyr in Siberia and Nome in Alaska are a few kilometres from each other, but when people are waking up and getting set for breakfast in these cities, it would be different days. II. When it is Monday in Anadyr, it is Tuesday in Nome. Which of the statements given above is/are correct?
Why
Statement I is correct, Anadyr (Russia) is just west of the International Date Line and Nome (Alaska) is just east, so they are very close geographically but on different calendar days; Statement II is wrong because when it is Monday in Anadyr it is still Sunday in Nome (Anadyr is ahead).
A person stood alone in a desert on a dark night and wanted to reach his village which was situated 5 km east of the point where he was standing. He had no instruments to find the direction but he located the polestar. The most convenient way now to reach his village is to walk in the:
Why
The Polestar (Polaris) lies almost exactly due north; to walk east, one must keep north to the left, so the polestar should be to the walker's left.
Consider the following statements: I. Without the atmosphere, temperature would be well below freezing point everywhere on the Earth's surface. II. Heat absorbed and trapped by the atmosphere maintains our planet's average temperature. III. Atmosphere's gases, like carbon dioxide, are particularly good at absorbing and trapping radiation. Which of the statements given above are correct?
Why
All three statements are correct: without the atmospheric greenhouse effect, Earth's surface would be far below freezing; heat is retained by the atmosphere, and CO2 and similar gases are effective absorbers of longwave radiation.
Consider the following statements:
Statement-I: The atmosphere is heated more by incoming solar radiation than by terrestrial radiation.
Statement-II: Carbon dioxide and other greenhouse gases in the atmosphere are good absorbers of long wave radiation. Which one of the following is correct in respect of the above statements?
Why
Statement I is incorrect because the atmosphere is actually heated more by terrestrial (longwave) radiation from Earth's surface than by direct incoming solar (shortwave) radiation; Statement II is correct as greenhouse gases efficiently absorb longwave radiation.
With reference to the Earth's atmosphere, which one of the following statements is correct?
Why
Water vapour concentrated in the lower troposphere is an effective absorber of infrared (longwave) radiation, making this the correct statement; the other options misstate facts about insolation, the solar spectrum, or visible light.
Consider the following statements: Statement I: The amount of dust particles in the atmosphere is more in subtropical and temperate areas than in equatorial and polar regions. Statement II: Subtropical and temperate areas have less dry winds. Which one of the following is correct in respect of the above statements?
Why
Subtropical and temperate zones do have more dust because of dry, arid conditions, but Statement II is wrong, these regions actually have more dry winds, not less, so it cannot explain the higher dust concentration.
With reference to 'water vapour', which of the following statements is/are correct?
Select the answer using the code given below:
Why
Water vapour does decrease with altitude as temperatures drop, but its concentration is maximum in tropical regions (not the poles), making only statement 1 correct.
Consider the following statements:
Statement-I: Thickness of the troposphere at the equator is much greater as compared to poles.
Statement-II: At the equator, heat is transported to great heights by strong convectional currents. Which one of the following is correct in respect of the above statements?
Why
The troposphere is thicker at the equator (~16 km) than at the poles (~8 km) because intense solar heating drives strong convection, lifting air and moisture to greater heights, which directly explains the greater thickness.
Consider the following statements:
Which of the statements given above is/are correct?
Why
High (cirrus) clouds primarily absorb and re-emit radiation rather than simply reflecting it, and low clouds act mainly to reflect solar radiation (cooling effect), not warm via infrared absorption, so both statements are incorrect as stated.
Why are dewdrops not formed on a cloudy night?
Why
Clouds reflect terrestrial radiation back to Earth, preventing the surface from cooling enough to reach dew point temperature; without sufficient cooling, water vapour cannot condense into dewdrops.
Normally, the temperature decreases with the increase in height from the Earth's surface, because:
Select the correct answer using the codes given below:
Why
Temperature decreases with altitude mainly because the atmosphere is heated from below (Earth's surface radiates longwave heat) and because air density decreases with height, reducing its capacity to retain heat; moisture is actually greater in the lower atmosphere, not the upper.
A layer in the earth's atmosphere called ionosphere facilitates radio communication. Why?
Which of the statements given above is/are correct?
Why
Radio wave reflection in the ionosphere is caused by the presence of free electrons and ions (not ozone), and it is the shorter shortwave radio frequencies (not long wavelengths) that are reflected back to Earth.
The jet aircrafts fly very easily and smoothly in the lower stratosphere. What could be the appropriate explanation?
Which of the statements given above is/are correct in this context?
Why
Both reasons are correct: the lower stratosphere is free of clouds and water vapour (so no turbulence from weather), and air movement is primarily horizontal with no vertical convection, giving smooth, fuel-efficient flight conditions.
Which of the following are the evidences of the phenomenon of continental drift? I. The belt of ancient rocks from Brazil coast matches with those from Western Africa. II. The gold deposits of Ghana are derived from the Brazil plateau when the two continents lay side by side. III. The Gondwana system of sediments from India is known to have its counterparts in six different landmasses of the Southern Hemisphere. Select the correct answer using the code given below.
Why
All three are classic geological evidences cited by Wegener for continental drift, matching rock belts, mineral deposit continuity across continents, and the pan-Southern Hemisphere distribution of Gondwana sediments.
Which of the following phenomena might have influenced the evolution of organisms?
Select the correct answer using the code given below.
Why
Continental drift isolated populations on separated landmasses driving speciation, and glacial cycles created dramatic environmental pressures that shaped evolutionary change, both phenomena significantly influenced the evolution of organisms.
Consider the following statements: Statement I: In the context of effect of water on rocks, chalk is known as a very permeable rock whereas clay is known as quite an impermeable or least permeable rock. Statement II: Chalk is porous and hence can absorb water. Statement III: Clay is not at all porous. Which one of the following is correct in respect of the above statements?
Why
Statement II is correct (chalk is porous and absorbs water, making it permeable) and explains Statement I; Statement III is incorrect because clay does have pores but its particles are so fine that water cannot flow through easily.
Consider the following statements:
Statement-I: Rainfall is one of the reasons for weathering of rocks.
Statement-II: Rain water contains carbon dioxide in solution.
Statement-III: Rain water contains atmospheric oxygen. Which one of the following is correct in respect of the above statements?
Why
Rainwater dissolves atmospheric CO₂ (forming carbonic acid) and also contains dissolved oxygen; both chemically react with minerals in rocks causing chemical weathering, so both statements are correct and both explain Statement I.
Consider the following:
Which of the above are responsible for bringing dynamic changes on the surface of the earth?
Why
All six factors contribute to surface dynamics, solar radiation drives weathering and climate, geothermal energy drives volcanism and plate tectonics, gravity shapes landforms, plate movements cause earthquakes and mountain building, and Earth's rotational and revolutionary motions influence winds, ocean currents, and seasons.
Consider the following statements: Statement I: Scientific studies suggest that a shift is taking place in the Earth's rotation and axis. Statement II: Solar flares and associated coronal mass ejections bombarded the Earth's outermost atmosphere with tremendous amount of energy. Statement III: As the Earth's polar ice melts, the water tends to move towards the equator. Which one of the following is correct in respect of the above statements?
Why
Both Statement II and III are individually correct, but only Statement III (redistribution of meltwater mass towards the equator altering Earth's moment of inertia) explains the observed axial shift; solar flares do not directly cause axial drift.
On June 21 every year, which of the following latitude(s) experience(s) a sunlight of more than 12 hours?
Select the correct answer using the code given below:
Why
On June 21 (summer solstice in the Northern Hemisphere), the Tropic of Cancer gets exactly 13.5 hours of sunlight and the Arctic Circle gets 24 hours; the equator always gets ~12 hours and the Tropic of Capricorn gets less than 12 hours on that date.
In the northern hemisphere, the longest day of the year normally occurs in the:
Why
The summer solstice in the Northern Hemisphere falls on June 21 or 22, which is in the second half of June, making it the longest day of the year.
On 21st June, the Sun:
Why
On June 21 (Northern Hemisphere summer solstice), the Arctic Circle experiences the midnight sun, the sun does not set; the Antarctic Circle, being in polar winter, has no sunlight at this time.
Variations in the length of daytime and night-time from season to season are due to?
Why
The tilt of Earth's axis (approximately 23.5°) relative to its orbital plane causes different parts of Earth to receive sunlight for varying durations as it revolves around the Sun, producing seasonal changes in day length.
Which of the following countries are well known as the two largest cocoa producers in the world?
Why
Côte d'Ivoire and Ghana together account for over 60% of global cocoa production, making them the two largest cocoa producers in the world.
Which one of the following is part of the Congo Basin?
Why
Cameroon's southeastern region falls within the Congo Basin drainage area, while Nigeria, South Sudan, and Uganda lie outside the Congo River's watershed.
Which one of the following lakes of West Africa has become dry and turned into a desert?
Why
Lake Faguibine in Mali has largely dried up due to reduced Niger River flooding and desertification, turning the former lake bed into a desert.
With reference to 'Coriolis force', which of the following statements are correct?
Select the answer using the code given below:
Why
Both statements are correct: Coriolis force is proportional to wind speed (faster winds deflect more) and is indeed maximum at the poles (where the rotation vector is vertical) and zero at the equator.
With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct?
Select the correct answer using the code given below:
Why
The IOD is defined by the difference in sea surface temperature between the western and eastern Indian Ocean (not Pacific), making statement 1 wrong; statement 2 is correct as a positive IOD can counteract El Nino's suppressing effect on the monsoon.
Consider the following statements:
Which of the statements given above is/are correct?
Why
Westerlies blow between roughly 30°–60° in both hemispheres (not 30°N to 60°S), making statement 1 wrong; statement 2 is correct as the western disturbances bringing winter rain to northwest India are embedded in the mid-latitude westerlies.
During a thunderstorm, the thunder in the skies is produced by the:
Select the correct answer using the codes given below.
Why
Thunder is the sound produced by the rapid expansion of air superheated by a lightning bolt, none of the three listed mechanisms (cloud collision, lightning separating clouds, or updrafts) is the actual cause.
Westerlies in southern hemisphere are stronger and persistent than in northern hemisphere. Why?
Which of the statements given above is/are correct?
Why
The Southern Hemisphere has far less landmass, so there is little friction or orographic disruption to weaken the westerlies; Coriolis force is equal in magnitude at the same latitudes in both hemispheres, so statement 2 is incorrect.
La Nina is suspected to have caused recent floods in Australia. How is La Nina different from El Nino?
Which of the statements given above is/are correct?
Why
Both statements are incorrect: La Nina involves unusually cold temperatures in the equatorial Pacific (not Indian Ocean), and La Nina generally enhances the Indian south-west monsoon rather than having no effect.
A new type of El Nino called El Nino Modoki appeared in the news. In this context, consider the following statements:
Which of the statements given above is/are correct?
Why
Statement 1 has the locations reversed, normal El Nino forms in the eastern Pacific and El Nino Modoki in the central Pacific; statement 2 is correct regarding their differing effects on Atlantic hurricane activity.
Consider the following description:
What is this type of climate?
Why
Marine West coast climate is characterised by mild temperatures (low annual range), year-round precipitation due to westerlies, and annual rainfall ranging between 50–250 cm, all of which match the description.
Consider the following statements:
Statement-I: The soil in tropical rain forests is rich in nutrients.
Statement-II: The high temperature and moisture of tropical rain forests cause dead organic matter in the soil to decompose quickly. Which one of the following is correct in respect of the above statements?
Why
Tropical rainforest soils are actually nutrient-poor (laterite soils leached by heavy rainfall), so Statement I is wrong; but Statement II is correct, rapid decomposition under heat and moisture means nutrients are quickly recycled and absorbed by plants, not stored in soil.
'Leaf litter decomposes faster than in any other biome and as a result the soil surface is often almost bare. Apart from trees, the vegetation is largely composed of plant forms that reach up into the canopy vicariously, by climbing the trees or growing as epiphytes, rooted on the upper branches of trees'. This is the most likely description of:
Why
Rapid leaf litter decomposition, bare soil surface, dense canopy, abundant climbers, and epiphytes are all hallmark features of tropical rainforests, where heat and humidity accelerate decomposition.
The vegetation of savannah consists of grassland with scattered small trees, but extensive areas have no trees. The forest development in such areas is generally kept in check by one or more or a combination of some conditions. Which of the following are such conditions?
Select the correct answer using the code given below.
Why
Fire, grazing herbivores, and seasonal (unreliable) rainfall are the primary checks on forest development in savannahs; burrowing animals and soil properties play a minor role in preventing tree establishment.
In the context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into stratosphere?
Why
Both cirrus cloud thinning and stratospheric aerosol injection are proposed geoengineering techniques aimed at reflecting solar radiation and thereby reducing global warming.
'Each day is more or less the same, the morning is clear and bright with a sea breeze; as the sun climbs high in the sky, heat mounts up, dark clouds form, than rain comes with thunder and lightning. But rain is soon over.' Which of the following regions is described in the above passage?
Why
The description of daily convectional afternoon thunderstorms that are brief and intense, with clear mornings and a sea breeze, is the classic pattern of equatorial climate (around 0°–10° latitude).
The seasonal reversal of winds is the typical characteristic of:
Why
Monsoon climate is uniquely characterised by the seasonal reversal of wind direction, onshore (wet) in summer and offshore (dry) in winter, which is not a feature of equatorial or Mediterranean climates.
Which of the following is/are unique characteristic/characteristics of equatorial forests?
Select the correct answer using the codes given below.
Why
All three, a dense multi-layered closed canopy, exceptional species diversity, and abundant epiphytes (orchids, ferns, bromeliads), are hallmark features of equatorial/tropical rainforests.
Which one of the following is the characteristic climate of the Tropical Savannah Region?
Why
Tropical savannah (Sudan type) climate is defined by a distinct alternation of a long dry season and a wet (summer) season, which determines the characteristic grass-woodland vegetation.
A geographical area with an altitude of 400 metres has following characteristics: temperature remains around 28–31°C throughout the year with high rainfall exceeding 1500 mm annually distributed across all months. If this geographic area were to have a natural forest, which one of the following would it most likely be?
Why
High temperatures (28–31°C) year-round with abundant evenly distributed rainfall exceeding 1500 mm at low altitude strongly indicate a tropical rainforest environment.
Consider the following:
How many of the above are products of volcanic eruptions?
Why
Volcanic eruptions eject pyroclastic debris, ash and dust, nitrogen-bearing gases, and sulphur dioxide/hydrogen sulphide, so all four listed items are genuine volcanic products.
Consider the following statements:
Which of the statements given above is/are correct?
Why
P (primary/compressional) waves travel faster than S (secondary/shear) waves and are recorded first; P waves are longitudinal (particles vibrate along direction of travel) while S waves are transverse (particles vibrate perpendicular to travel direction), both statements are correct.
The word 'Denisovan' is sometimes mentioned in media in reference to:
Why
Denisovans are an extinct species or subspecies of archaic humans, identified from DNA and fossils found in Denisova Cave in Siberia, distinct from but related to Neanderthals and modern humans.
Which one of the following sets of elements was primarily responsible for the origin of life on the Earth?
Why
Life is fundamentally built on organic molecules, and the primordial atmosphere/ocean contained Carbon, Hydrogen, Nitrogen (along with oxygen and sulphur) as the key elements for forming amino acids and nucleotides.
With reference to the water on the planet Earth, consider the following statements: 1) The amount of water in the rivers and lakes is more than the amount of groundwater. 2) The amount of water in polar ice caps and glaciers is more than the amount of groundwater. Which of the statements given above is/are correct?
Why
Polar ice caps and glaciers hold roughly 69% of the world's fresh water, which far exceeds groundwater (~30%), while rivers and lakes together hold only a tiny fraction.
Consider the following statements:
Which of the statements given above is/are correct?
Why
Less than 3% of Earth's water is fresh, and of that only a small fraction is accessible (making usable fresh water under 1% of total water), but approximately 69% (not 95%) of fresh water is locked in ice caps and glaciers.
The black cotton soil of India has been formed due to the weathering of:
Why
Black cotton soil (regur) is formed from the weathering of Deccan Trap basaltic lava rocks that erupted through fissures, giving the soil its characteristic dark colour and high moisture retention.
Which of the is/are the possible consequences of heavy sand mining in riverbeds?
Select the correct answer using the code below:
Why
Heavy sand mining disrupts the riverbed aquifer, allowing pollutants to enter groundwater, and lowers the water table; it does not decrease salinity, that is unrelated to sand extraction.
In India, the problem of soil erosion is associated with which of the following?
Select the correct answer using the code given below.
Why
Deforestation is the primary cause of soil erosion in India; terrace cultivation actually helps prevent erosion by slowing runoff, and tropical climate alone does not cause erosion without loss of vegetation cover.
Which of the following statements regarding laterite soils of India are correct?
Select the correct answer using the codes given below.
Why
Laterite soils are red due to iron content and support crops like tapioca and cashew; they are deficient in nitrogen and potash and are found mainly in humid peninsular regions, not Rajasthan or UP.
On the planet earth, most of the freshwater exists as ice caps and glaciers. Out of the remaining freshwater, the largest proportion?
Why
After ice caps and glaciers, groundwater constitutes by far the largest share of remaining freshwater on Earth (~30% of all freshwater), vastly exceeding surface water in rivers and lakes.
Contour Bunding is a method of soil conservation used in?
Why
Contour bunding involves constructing earthen embankments along contour lines on sloping land to intercept runoff and reduce soil erosion; it is used on slopes, not specifically in desert margins, flood plains, or scrublands, making 'none of the above' the correct answer in the context of those specific descriptions.
Consider the following statements: 1) The Global Ocean Commission grants licences for seabed exploration and mining in international waters. 2) India has received licences for seabed mineral exploration in international waters. 3) 'Rare earth minerals' are present on seafloor in international waters. Which of the statements given above are correct?
Why
Seabed mining licences in international waters are granted by the International Seabed Authority (not the Global Ocean Commission), but India does hold such licences and rare earth minerals are indeed found on the deep ocean floor.
Consider the following statements:
Which of the statements given above is/are correct?
Why
Jet streams occur in both hemispheres, so statement 1 is wrong; the eye of a cyclone is actually warmer (not cooler) than its surroundings, so statement 3 is wrong; only statement 2 is correct, only intense tropical cyclones typically develop a clear eye.
In the South Atlantic and South Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason?
Why
The ITCZ rarely moves into the South Atlantic and South-East Pacific, so the low-pressure convergence zone needed to initiate cyclone formation is absent in these regions.
Consider the following statements about Particularly Vulnerable Tribal Groups (PVTGs) in India:
Which of the statements given above are correct?
Why
There are 75 (not 95) officially notified PVTGs; statements 1, 2, and 4 are correct, making option c the right answer.
What explains the eastward flow of the equatorial counter-current?
Why
The North and South Equatorial Currents pile up warm water on the western side of oceans; as they converge and water level rises, a return flow develops eastward as the Equatorial Counter-Current.
Tides occur in oceans and seas due to which of the following?
Select the correct answer using the code given below:
Why
Tides result from the combined gravitational pull of the Moon (primary) and the Sun, while Earth's own gravity keeps ocean water from flying off, so all three forces are involved.
The most important fishing grounds of the world are found in the regions where?
Why
Where warm and cold ocean currents converge, upwelling brings nutrients to the surface, supporting rich plankton growth and consequently dense fish populations.
Consider the following factors:
Which of the above factors influence the ocean currents?
Why
Ocean currents are driven by surface winds and air pressure differences, deflected by Earth's rotation (Coriolis effect), and influenced by water density variations; Earth's revolution (around the Sun) does not directly drive ocean currents.
What could be the main reason/reasons for the formation of African and Eurasian desert belt?
Which of the statements given above is/are correct in this context?
Why
The Sahara–Arabian–Thar desert belt lies under subtropical high-pressure cells where air descends and dries out; cold (not warm) offshore currents also contribute on the western coasts, so Statement 2 is incorrect.