Hydrosphere - Oceans and Water PYQs – Geography, SSC & Railway

Correct Answer:
Correct Answer: Option 1 – Earth's rotation deflects water movement
Explanation:
Ocean gyres are large systems of rotating currents driven mainly by wind, but their specific rotational direction (clockwise in the Northern Hemisphere, counter-clockwise in the Southern Hemisphere) is determined by theCoriolis effect, which results from the Earth's rotation deflecting moving water (and air) — to the left in the Southern Hemisphere and to the right in the Northern Hemisphere.
Important Facts:
• The Coriolis effect is zero at the equator and increases toward the poles.
• Major Southern Hemisphere gyres include the South Pacific, South Atlantic, and Indian Ocean gyres, all rotating anticlockwise.

Correct Answer:
Option 4 – Upwelling caused by ocean currents
Explanation:
Upwellingis the physical oceanographic process in which cold, nutrient-rich water from the ocean depths rises to the surface, often driven by winds and ocean currents pushing surface water away from the coast. This process supports high productivity of phytoplankton, which in turn sustains large fish populations — a phenomenon well known near continental shelf/coastal fishing grounds.
Important Facts:
• Major upwelling zones (e.g., off Peru, California) are among the world's richest fishing grounds.
• Downwelling is the opposite process, where surface water sinks.
Correct Answer: Option 4 – Upwelling caused by ocean currents

Answer: Option 4 — Ocean warming lowers CO₂ absorption and stresses marine life
Concept (interaction of spheres):Higher global temperature (atmosphere) warms ocean water (hydrosphere). Warm water dissolvesless CO₂and holds less oxygen, and the heat stress causescoral bleachingand promotes harmfulalgal blooms(biosphere). This links atmosphere–hydrosphere–biosphere → Option 4.
(Options 1–3 are scientifically wrong: less sunlight would reduce photosynthesis, etc.)

Answer: Option 2 — 2 → 1 → 3 → 4
Water cycle order:Evaporation → Condensation → Precipitation → Collection= 2 → 1 → 3 → 4 → Option 2.

Topic: Ocean Floor Features
Mid-Oceanic Ridges:
Underwater mountain chains formed by tectonic plate divergence.
Central rift valley with active volcanic activity.
Example: Mid-Atlantic Ridge, East Pacific Rise.
Other Options:
Deep-ocean trenches → Deepest parts, convergent boundaries.
Abyssal plains → Flat ocean floor areas.
Continental slope → Transition from shelf to deep ocean.
Answer: Option 4 → Mid-oceanic ridges

Correct Answer: Only II (Option 2)
Statement I is INCORRECT: Water stored in ice and snow is released through MELTING or SNOWMELT, not transpiration. Transpiration is the process by which plants absorb water from the soil and release it as water vapour through their leaves. It is not associated with ice and snow storage.
Statement II is CORRECT: Groundwater stored in aquifers is naturally discharged to the surface through springs. When the water table rises and intersects with the ground surface (especially on hillsides or valley floors), water flows out as a spring. This is a well-established component of the water cycle.
Therefore, only Statement II is correct.

Correct Answer: Tides (Jowar- Bhata ) — Option (c)
The given description perfectly defines Tides ( ज्वार - भाटा /Jowar- Bhata ). About Tides: Definition: The periodic rise and fall of sea water level caused by the gravitational forces exerted by the Moon and Sun and the rotation of the Earth; Frequency: Semidiurnal tides = rise and fall TWICE a day (approximately every 12 hours 25 minutes); Cause: Gravitational pull of the Moon (primary cause — stronger effect despite greater distance) and the Sun (secondary cause) on Earth's oceans; The Moon's gravitational pull creates a water bulge on the side of Earth facing the Moon (high tide) and on the opposite side (due to centrifugal effect); As Earth rotates, different areas pass through these bulges, causing two high tides and two low tides daily; Types of tides: Spring tides: When Sun, Moon, and Earth are aligned (new moon or full moon) — very high tides; Neap tides: When Sun and Moon are at right angles to Earth — moderate tides; Diurnal tides: One high tide and one low tide per day; Semidiurnal tides: Two high tides and two low tides per day (most common — as described in the question); Significance of tides: Navigation and shipping; Tidal energy (renewable energy); Fishing activities; The description in the question matches Tides exactly: 'Rise and fall twice a day' = semidiurnal tides ✓ ; 'Gravitational force of Sun and Moon' = cause of tides ✓ .
Option (a) Tsunami — Incorrect: A Tsunami is a series of ocean waves caused by underwater earthquakes, volcanic eruptions, or landslides — NOT by gravitational pull of Sun and Moon; tsunamis are NOT a regular daily occurrence (they are sudden catastrophic events); the description does NOT match tsunami. The candidate selected this incorrect option.
Option (b) Cyclone — Incorrect: A Cyclone is a large-scale weather system characterized by low atmospheric pressure and strong rotating winds — it is caused by atmospheric pressure differences and the Coriolis effect, NOT by gravitational pull of the Sun and Moon; cyclones are not regular twice-daily events.
Option (d) Western Disturbance — Incorrect: Western Disturbance is a weather phenomenon (extra-tropical cyclone) that brings non-monsoonal winter rainfall to northwestern India — it is caused by moisture-laden winds from the Mediterranean Sea; it has no connection to the regular twice-daily rise and fall of ocean water due to gravitational forces.

North Atlantic Drift(extension of Gulf Stream) carries warm tropical water from Caribbean to Western Europe.
This warm current raises temperatures of UK, Ireland, Norway by 5-10°C compared to similar latitudes.
Other options: Canary Current (cold), Humboldt Current (cold, South America), Oyashio Current (cold, Japan).
Answer: Option 2 → North Atlantic Drift

Canary Current
The Canary Current is a cold ocean current.
It flows along the northwest coast of Africa.
It is part of the North Atlantic Gyre system.
Flows southward from the North Atlantic towards the equator.
Answer: Option 4 → Atlantic Ocean

Water in a dug well is collected from water-bearing strata.
Water-bearing strata, also called aquifers, are permeable layers of rock or sediment that hold water.
Impervious strata do not allow water to pass through, so they do not contribute to water in wells.
Deep strata or neighbouring strata are not specific terms related to water collection in wells.
Hence, water-bearing strata is the correct and scientific source of water in dug wells.

India's Deep Ocean Mission (approved in 2021) has primary strategic relevance for exploring and mining polymetallic nodules from the Central Indian Ocean Basin (CIOB). These nodules contain manganese, nickel, copper, and cobalt. India has been allocated an Exclusive Economic Zone of 75,000 sq km in CIOB by the International Seabed Authority.
(a) Incorrect: Arctic fisheries fall outside India's Deep Ocean Mission scope; the mission focuses on the Indian Ocean.
(b) Incorrect: Adriatic Sea is located between Italy and the Balkans — far from India's ocean jurisdiction and the mission's scope.
(c) Incorrect: Malacca Strait connectivity is a strategic maritime trade concern, not related to deep ocean mineral exploration.

The Java Trench (also called the Sunda Trench) is the deepest part of the Indian Ocean, located south of the islands of Java and Sumatra. It reaches a maximum depth of approximately 7,258 metres (23,812 feet) and is the site of significant tectonic activity including the 2004 Indian Ocean earthquake and tsunami.
(a) Incorrect: Mariana Trench is the deepest trench in the Pacific Ocean (and the world), reaching ~11,034 metres ; it is not in the Indian Ocean.
(b) Incorrect: Puerto Rico Trench is the deepest point in the Atlantic Ocean and Caribbean; it is not in the Indian Ocean.
(c) Incorrect: Tonga Trench is in the South Pacific Ocean; it is the second deepest trench in the world but is not in the Indian Ocean.

The Great Barrier Reef, the world's largest coral reef system spanning over 2,300 km, is located along the northeastern coast of Queensland, Australia. It is a UNESCO World Heritage Site and one of the most biodiverse marine ecosystems on Earth.
(a) Incorrect: Indonesia has coral reefs within the Coral Triangle but does not host the Great Barrier Reef.
(b) Incorrect: The Philippines is also part of the Coral Triangle but is not home to the Great Barrier Reef.
(c) Incorrect: The Maldives is known for its atolls and coral reefs, but the Great Barrier Reef is exclusively in Australia.

Correct Answer: Indian National Centre for Ocean Information Services (INCOIS)
INCOIS (Indian National Centre for Ocean Information Services), under the Ministry of Earth Sciences, provides coral bleaching alert services for Indian coral reefs using sea surface temperature data. It monitors thermal stress on coral reefs and issues warnings to help manage and protect coral ecosystems.
Option 1 (CMFRI): Incorrect. CMFRI focuses on marine fisheries research.
Option 2 (ZSI): Incorrect. ZSI surveys animal life; doesn't provide bleaching alerts.
Option 4 (Ministry): Incorrect. Policy ministry; actual monitoring is done by INCOIS.

Correct Answer: Option 1 – Matsya-6000
Matsya-6000 is the name of the 4th Generation deep-ocean human scientific submersible being developed by the National Institute of Ocean Technology (NIOT) as part of India's Samudrayan Project. The submersible is designed to carry three persons to a depth of 6,000 metres under the ocean surface for deep-sea research and mineral exploration.
Why other options are wrong:
Option 2 (Samudra-5000): This is not the name of the submersible in the Samudrayan Project.
Option 3 (Manimekhala-6000): This is an incorrect name; the candidate incorrectly selected this.
Option 4 (Shankha-5000): This is also an incorrect name for the submersible.

Correct Answer: Deep Ocean Mission (Option 3)
MATSYA 6000 is India's first indigenously developed crewed submersible (manned deep-sea vessel), designed to dive up to 6,000 metres below the ocean surface. It is a key component of India's Deep Ocean Mission, launched by the Ministry of Earth Sciences. MATSYA 6000 will carry three persons and support deep sea exploration for minerals, biodiversity, and energy resources.
Aditya L-1 Mission — India's first solar observatory mission placed in the L1 halo orbit to study the Sun.
Shukrayaan Mission — India's planned Venus orbiter mission.
Gagan Yaan Mission — India's human spaceflight programme to send Indian astronauts to low Earth orbit.

AMOC slowdown is expected to:
– Disrupt tropical monsoons (true).
– Cause cooling over the North Atlantic (true).
– Raise sea levels along the US East Coast (true, due to water piling up).
It is NOT expected to cause increased warming in the Arctic — in fact, weakening AMOC typically leads to cooling around the North Atlantic/Arctic.
Hence, Option 3 is the correct (NOT a consequence) answer.

Major coral reef ecosystems in India are found in:
Gulf of Kutch (Gujarat).
Gulf of Mannar (Tamil Nadu).
Lakshadweep Islands.
Andaman & Nicobar Islands.
Deltaic and deep-sea environments are not suited for corals.

Correct Answer: Option 3 – Gravitational pull of the Moon and Sun
Tides are caused primarily by the differential gravitational pull of the Moon (and to a lesser extent, the Sun) on Earth's oceans. The Moon's gravity pulls the water on the near side of Earth more strongly than the Earth's center, and pulls the Earth's center more strongly than the water on the far side — creating two tidal bulges (high tides) simultaneously on opposite sides of Earth. The Moon contributes about 2/3 of the tidal force; the Sun about 1/3. Spring tides (highest) occur during new and full moon when Moon-Sun-Earth align; neap tides (lowest) occur during quarter moons.
Option 1 (Solar energy): Solar energy drives atmospheric circulation and ocean surface heating, but is not the primary cause of tides.
Option 2 (Ocean currents): Ocean currents (thermohaline circulation, wind-driven surface currents) are distinct from tides and have different driving mechanisms.
Option 4 (Wind patterns): Wind creates surface waves and can affect local sea levels (storm surge), but is not the primary cause of regular tidal cycles.

Correct Answer: Option 2 – Solar energy
The water cycle (hydrological cycle) is primarily driven by solar energy. The sun's heat causes evaporation of water from oceans, lakes, and rivers. This water vapour rises, condenses to form clouds, and eventually falls as precipitation, completing the cycle.
Option 1 (Geothermal energy): Plays a minor role in some geothermal regions but is not the primary driver.
Option 3 (Wind energy): Winds help transport water vapour but are themselves driven by solar energy; they are a secondary factor.
Option 4 (Ocean tides): Caused by gravitational pull of the Moon; not related to the water cycle.

Correct Answer: Option 3 – For both economic and environmental reasons
Subsurface fluid reservoirs (such as groundwater aquifers and oil/gas reservoirs) are important for both economic and environmental reasons.
Economic reasons: Extraction of oil, natural gas, and groundwater supports energy production, agriculture, and industry.
Environmental reasons: Improper management can cause land subsidence, induced seismicity (earthquakes), and groundwater contamination.
Option 1 (Only environmental): Incorrect; economic importance is equally significant.
Option 2 (Only economic): Incorrect; environmental consequences are equally critical.
Option 4 (Neither): Incorrect; both dimensions are highly relevant.

Correct Answer: Option 1 – Statement 1 only
Statement 1 (TRUE): Abyssal plains are extensive, remarkably flat regions of the deep ocean floor, typically found at depths of 3,000–6,000 metres . They cover approximately 50% of the Earth's surface, making them one of the most widespread environments on the planet. They are among the flattest, smoothest terrains on Earth, formed by the accumulation of fine sediments (oozes) that gradually bury the uneven underlying topography.
Statement 2 (FALSE): Oceanic trenches are NOT shallow depressions — they are the deepest parts of the ocean, forming elongated depressions that can reach extreme depths. The Mariana Trench in the Pacific Ocean is the world's deepest point (~11,034 metres / ~36,089 feet). Trenches form at subduction zones where one tectonic plate dives beneath another. They are deep (not shallow), narrow, and steep-sided.

Correct Answer: Option 3 – Wind & Density
Earth's large-scale ocean circulation is driven by two primary forces: (1) Wind — surface winds drive surface ocean currents (e.g., Trade winds drive equatorial currents; Westerlies drive mid-latitude currents). (2) Density differences (thermohaline circulation) — driven by variations in water temperature (thermo) and salinity (haline), which affect water density. Cold, salty water is denser and sinks, driving deep-ocean circulation (the global conveyor belt/AMOC). Together, wind-driven and density-driven circulations constitute the full ocean current system.
Option 1 (Tides & Moon): Tidal currents are driven by gravitational pull of Moon and Sun but are localized and oscillatory — not large-scale ocean circulation drivers.
Option 2 (Earthquakes & Volcanoes): These are geological events that can trigger tsunamis — not the primary drivers of large-scale sustained ocean currents.
Option 4 (Salinity & Temperature): While salinity and temperature differences drive thermohaline (density) circulation, they represent only ONE of the two primary factors. Wind is the other — so this option is incomplete.

Correct Answer: Option 4 — Tides
Tides are the regular rise and fall of sea water, and they are caused mainly by the gravitational pull of the Moon on the Earth's oceans, helped to a smaller extent by the Sun. Water on the side of the Earth facing the Moon is pulled towards it and bulges out, producing a high tide; a second bulge forms on the opposite side because the solid Earth itself is pulled away from the water there. Regions at right angles to these bulges experience a low tide.
Because the Earth rotates once in about 24 hours while these bulges stay lined up with the Moon, most coasts get two high tides and two low tides in roughly 24 hours 50 minutes.
When the Sun, Moon and Earth lie in a straight line (new moon and full moon), the two pulls add and we get the highest tides, called spring tides. When the Sun and Moon are at right angles (first and last quarter), the pulls partly cancel and we get the weakest tides, called neap tides.
❌ Why the other options are incorrect
✗ Blue color of the sky — caused by the scattering of light by air molecules (Rayleigh scattering), in which blue is scattered most because of its short wavelength.
✗ Thunderstorms — a weather phenomenon produced by convection currents, moisture and electrical discharge in clouds, not by lunar gravity.
✗ Rainbow — formed by refraction, total internal reflection and dispersion of sunlight in water droplets; it is an optical, not a gravitational, effect.
📌 SSC & Railway Exam Facts
• Tides are mainly due to the Moon's gravitational pull; the Moon's tidal effect is about twice that of the Sun because it is far closer.
• Spring tides — Sun, Moon and Earth in a line (full moon/new moon); neap tides — Sun and Moon at 90°.
• F = GMm/r²; G = 6.67 × 10⁻¹¹ N m² kg⁻², measured by Henry Cavendish.
• The Moon's gravity is about 1/6 of the Earth's, so weight on the Moon is one-sixth of that on the Earth.
• Gravitation also explains the orbits of planets (Kepler's laws), the revolution of the Moon and the free fall of bodies.