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Physical Geography

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Question 201Question →

Match each Köppen climate classification symbol on the left with its corresponding atmospheric control mechanism and seasonal precipitation regime on the right.

Click a left item, then click its matching right item

Items

AfAf
AmAm
CsCs
BWkBWk

Matches

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Answer

AfAf matches continuous year-round ITCZ rainfall; AmAm matches marked seasonal monsoonal rain with a brief dry season; CsCs matches summer drought from subtropical highs and winter rain from westerlies; BWkBWk matches mid-latitude desert aridity from continentality and rain shadows.
Each Köppen symbol accurately maps to its driving atmospheric control: AfAf relies on perpetual equatorial ITCZ uplift; AmAm depends on seasonal monsoonal wind reversals; CsCs is governed by the seasonal migration of subtropical high-pressure cells and mid-latitude westerlies; and BWkBWk is created by rain shadows and continental isolation at middle latitudes.

Step-by-Step Solution

1
Analyze the thermal and moisture parameters represented by each Köppen climate code.
Identify that AA represents tropical climates, CC represents warm temperate climates, and BB represents arid climates.
Establishing primary climate groups establishes the primary latitude and temperature bounds for matching.
2
Match the second-letter modifiers (ff, mm, ss, WW) and third-letter temperature modifier (kk) to seasonal precipitation patterns.
ff indicates fully humid year-round, mm indicates monsoonal rain, ss indicates dry summer, and WkWk indicates cold desert conditions.
The lower-case secondary letters specify the exact rainfall regime and seasonal controls.
3
Pair each symbol with its corresponding atmospheric mechanism.
AfAf pairs with ITCZ convergence, AmAm with seasonal onshore monsoon flows, CsCs with subtropical subsidence and westerly winter shifts, and BWkBWk with continentality and rain-shadow effects.
Atmospheric pressure belts and ocean-continent positions dictate the physical controls behind each climate type.

Key Concept

Köppen Climate Classification and Controlling Atmospheric Mechanisms
Question 202Question →

In humid tropical regions experiencing high temperatures and heavy seasonal rainfall, intense leaching removes silica and soluble bases from the soil profile while leaving behind insoluble hydrated oxides of iron and aluminum. Which pedogenic process is responsible for this soil development?

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Answer: Lateritization

Answer

Lateritization
Lateritization is the dominant soil-forming process in humid tropical and sub-tropical climates with high rainfall and warm temperatures. Rapid chemical weathering and intense leaching remove soluble silica and bases from the topsoil, leaving behind resistant, insoluble iron and aluminum sesquioxides that produce reddish lateritic soils.

Step-by-Step Solution

1
Analyze the climatic context and chemical mechanism described in the stem.
High temperatures and heavy rainfall in humid tropics promote intense leaching (eluvial removal of silica and soluble salts).
Climatic controls dictate the specific weathering and pedogenic pathways in soil profile development.
2
Identify the resulting mineral accumulation.
Residual accumulation of insoluble hydrated oxides of iron (Fe) and aluminum (Al), giving tropical soils their characteristic reddish oxide crust.
Desilication removes silica compounds, concentrating insoluble sesquioxides in the profile.
3
Match the process with its corresponding pedogenic term.
The process described is lateritization (ferralitization), resulting in lateritic soil/oxisol formation.
Lateritization is the precise pedogenic term for sesquioxide enrichment via tropical desilication.

Key Concept

Lateritization and Tropical Soil Pedogenic Processes
Question 203Question →

Geological analysis of the Earth's crust reveals distinct compositional and physical differences between continental and oceanic sectors. Which of the following statements accurately describes the relationship between the sial and sima layers?

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Answer: Sial is rich in silica and aluminium, forming a lighter granitic layer that floats upon the denser basaltic sima layer composed of silica and magnesium.

Answer

Sial is rich in silica and aluminium, forming a lighter granitic layer that floats upon the denser basaltic sima layer composed of silica and magnesium.
The sialic layer (silica and aluminium) forms the lighter continental crust with an average density of 2.7 g/cm³, resting directly above the denser simaic layer (silica and magnesium, 3.0 g/cm³) which constitutes the oceanic crust and continuous lower crustal foundation.

Step-by-Step Solution

1
Analyze the chemical composition denoted by the names sial and sima.
Sial derives from Silica and Aluminium (granitic composition), whereas Sima derives from Silica and Magnesium (basaltic composition).
These chemical elements form the essential constituent minerals of the upper and lower crust.
2
Determine the relative density and structural positioning of these layers within the lithosphere.
Sial has an average density of 2.7 g/cm³ and forms the upper continental crust, while sima has an average density of 3.0 g/cm³ and forms the oceanic floor beneath sial.
Principle of isostasy dictates that lighter granitic rocks float on top of denser basaltic substrates.

Key Concept

Composition and structural characteristics of the Earth's crust (Sial and Sima)
Question 204Question →

A radio station located at longitude 10∘W10^\circ\text{W} begins a live news broadcast at 2:15 p.m.2:15\text{ p.m.} local solar time. What is the local solar time at a receiving station located at longitude 35∘E35^\circ\text{E} when the broadcast is heard?

Show answer & explanation

Answer: 5:15 p.m.5:15\text{ p.m.}

Answer

5:15 p.m.5:15\text{ p.m.}
The correct response of 5:15 p.m.5:15\text{ p.m.} is derived by calculating the total longitudinal distance of 45∘45^\circ (10∘W+35∘E10^\circ\text{W} + 35^\circ\text{E}), converting it to a 3-hour difference (45∘/15∘=3 hours45^\circ / 15^\circ = 3\text{ hours}), and adding 3 hours to the transmitting local time (2:15 p.m.2:15\text{ p.m.}) because the destination lies to the east.

Step-by-Step Solution

1
Calculate the total angular distance between the transmitting and receiving longitudes.
10∘W+35∘E=45∘10^\circ\text{W} + 35^\circ\text{E} = 45^\circ
Since the two positions are in opposite hemispheres (West and East), their longitudinal values must be added together.
2
Convert the total angular distance into a time difference.
\frac{45^\circ}{15^\circ\text{ per hour}} = 3\text{ hours}
The Earth rotates 360∘360^\circ in 24 hours, which equals 15∘15^\circ of longitude per hour.
3
Adjust the initial local solar time according to relative direction.
2:15 p.m.+3 hours=5:15 p.m.2:15\text{ p.m.} + 3\text{ hours} = 5:15\text{ p.m.}
Because Earth rotates from west to east, locations situated further east experience solar time ahead of locations to the west.

Key Concept

Longitude and Local Solar Time Calculation
Estimated Time:1m 30s
Question 205Question →

Which of the following instruments is specifically used to measure wind speed at a weather station?

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Answer: Anemometer

Answer

The instrument specifically used to measure wind speed is the anemometer.
An anemometer is designed with cups or vanes that rotate as wind passes across them; the rotation rate directly corresponds to wind speed.

Step-by-Step Solution

1
Identify the weather element specified in the question stem.
The target weather element to measure is wind speed.
Different atmospheric parameters require specific recording instruments.
2
Match the targeted element (wind speed) to its corresponding standard measuring instrument.
The anemometer (commonly a cup anemometer) is the standard instrument that measures wind speed in meters per second or knots.
The rotating cups of an anemometer spin at a rate proportional to wind speed.

Key Concept

Weather Elements and Instruments
Question 206Question →

Match each environmental hazard in Nigeria with its primary environmental impact.

Click a left item, then click its matching right item

Items

Oil Spillage
Coastal Erosion
Indiscriminate Refuse Disposal

Matches

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Answer

Oil Spillage pairs with contamination of aquatic and mangrove ecosystems in the Niger Delta; Coastal Erosion pairs with shoreline retreat and beachfront damage in Lagos; Indiscriminate Refuse Disposal pairs with drain blockages causing urban flash floods.
Each hazard is accurately matched to its principal ecological or infrastructural consequence in Nigeria based on regional environmental geography.

Step-by-Step Solution

1
Identify the primary geographic location and ecological impact of crude oil discharge.
Oil spillage directly contaminates creeks, soil, and mangrove swamps in the Niger Delta.
Petroleum exploration activities are concentrated in the coastal Niger Delta region.
2
Analyze oceanographic processes along coastal settlements like Lagos.
Wave scouring along the Atlantic oceanfront causes coastal erosion and land loss on Victoria Island and surrounding shores.
High-energy Atlantic waves continuously scour unprotected sandy shores.
3
Evaluate urban human activities regarding waste management.
Dumping trash into gutters causes drainage clogging and severe flash flooding during heavy rainstorms.
Unmanaged solid waste obstructs surface runoff routes in major cities.

Key Concept

Environmental Hazards and Regional Impacts in Nigeria
Estimated Time:1m 0s
Question 207Question →

During glacial retreat, unsorted and unstratified rock debris carried by a glacier is deposited directly by the melting ice to form ridges along the edges and snout of the glacial valley. Which of the following landforms is formed by this process?

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Answer: A moraine

Answer

A moraine is the correct landform formed by the direct deposition of unsorted glacial till during ice retreat.
Moraines are formed when glaciers retreat and deposit unsorted rock fragments and sediment (till) directly onto the landscape. Depending on their position relative to the glacier, they form lateral, medial, or terminal ridges.

Step-by-Step Solution

1
Identify the primary agent of erosion and deposition described in the scenario
The process involves melting ice and glacial retreat, placing the feature under glacial depositional landforms.
Glacial deposition is distinct from running water (fluvial) or gravitational mass wasting processes.
2
Analyze the material characteristics and geometry of the landform
The material is unsorted rock debris (till) forming ridges along the glacial margins and snout.
Glaciers deposit unsorted debris (till) directly, which accumulates into ridges known as terminal, lateral, or medial moraines.
3
Evaluate the options to rule out non-glacial processes
Oxbow lakes and river deltas are formed by running water in river systems, while scree slopes are formed by mechanical weathering and mass wasting under gravity.
Only moraines fit the definition of direct deposition of unsorted till by a glacier.

Key Concept

Glacial Deposition and Till Landforms
Estimated Time:1m 0s
Question 208Question →

Northwestern Europe experiences significantly milder winter temperatures and a lower annual temperature range than inland regions of Eurasia situated at the same latitude (55∘N55^\circ\text{N}). Which climatic control is primarily responsible for this maritime moderation?

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Answer: The poleward transport of sensible heat by the warm North Atlantic Drift combined with prevailing westerly winds

Answer

The poleward transport of sensible heat by the warm North Atlantic Drift combined with prevailing westerly winds is the primary climatic control moderating Northwestern Europe's climate.
The North Atlantic Drift carries warm ocean water from the low latitudes towards Northwestern Europe. The prevailing westerly winds pass over this warm ocean current, absorbing moisture and heat, which is then carried inland. This maritime control keeps winter temperatures unusually mild for 55∘N55^\circ\text{N} latitude and reduces the annual thermal range.

Step-by-Step Solution

1
Identify the geographical context and anomaly described in the prompt.
Northwestern Europe at latitude 55∘N55^\circ\text{N} has unexpectedly mild winters compared to continental interiors like Siberia at the same latitude.
Understanding land-water heating contrasts and ocean current dynamics is fundamental to evaluating temperature ranges.
2
Analyze the major climatic controls influencing mid-latitude coastal zones.
Ocean currents (North Atlantic Drift) carry warm tropical waters northward, and prevailing onshore Westerly winds blow over this warm surface water onto the European landmass.
This oceanic heat transport prevents severe freezing in winter and suppresses extreme summer heat, keeping annual thermal ranges narrow.

Key Concept

Ocean Currents and Maritime vs. Continental Controls
Estimated Time:1m 0s
Question 209Question →

Arrange the following sequential stages in the process of soil salinization—a major form of environmental land degradation in semi-arid agricultural zones—from the initial human activity to the ultimate ecological impact.

Drag items to arrange them in the correct order

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Answer

The correct sequence of soil salinization begins with excessive irrigation on poorly drained land, followed by capillary uptake of saline groundwater, surface water evaporation leaving salt deposits, and ultimately the formation of a toxic saline crust that causes crop failure.
The correct sequence follows the hydro-geological progression of land salinization. Over-irrigation on poorly drained agricultural land first saturates the subsurface. Capillary forces then pull the saline groundwater upward into topsoil layers. Rapid surface evaporation under hot, dry conditions removes pure moisture while leaving concentrated mineral salts behind. Finally, continuous salt accumulation forms a toxic surface crust that destroys soil structure and prevents plant water uptake.

Step-by-Step Solution

1
Identify the initial triggering activity
Excessive irrigation water applied to poorly drained soil introduces surplus moisture into the ground.
Human-induced over-irrigation raises the local water table, initiating the hydraulic process.
2
Determine the physical subsurface movement
Capillary action draws the salt-rich groundwater upward toward the surface root zone.
Water moves from saturated subsoil layers to drier upper soil horizons due to surface tension and soil pore suction.
3
Analyze the climatic driving mechanism
High surface evaporation under hot semi-arid conditions vaporizes moisture, concentrating salts.
Evaporation isolates mineral ions such as sodium and chloride near the surface.
4
Establish the final degradation consequence
Formation of a toxic saline crust leads to severe osmotic stress, vegetation destruction, and land degradation.
Hyper-saline topsoil prevents root water absorption and breaks down soil aggregate structure.

Key Concept

Soil Salinization and Land Degradation Mechanics in Semi-Arid Environments
Question 210Question →

Match each environmental hazard and degradation process observed in West Africa with its underlying physical mechanism and environmental consequence.

Click a left item, then click its matching right item

Items

Coastal Lagoon Inundation and Aquifer Salinization
Soil Salinization in Irrigated Arid Basins
Atmospheric Acidification from Gas Flaring
Headwater Gully Rejuvenation and Basin Siltation

Matches

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Answer

Coastal Lagoon Inundation and Aquifer Salinization matches with marine wave erosion and groundwater over-extraction leading to estuarine dieback. Soil Salinization in Irrigated Arid Basins matches with intense evapotranspiration and poor drainage creating mineral crusts that impede root osmotic uptake. Atmospheric Acidification from Gas Flaring matches with sulfur and nitrogen oxide emissions altering soil pH and corroding structures. Headwater Gully Rejuvenation and Basin Siltation matches with surface runoff concentration after canopy removal causing channel incision and downstream sedimentation.
Each degradation hazard is accurately matched to its specific environmental mechanism and consequence: coastal intrusion stems from marine erosion and groundwater withdrawal; dryland salinization arises from capillary action and high evaporation in irrigation schemes; atmospheric acidification is driven by hydrocarbon combustion byproducts altering pH; and gully rejuvenation proceeds from vegetation removal accelerating surface runoff and downstream sedimentation.

Step-by-Step Solution

1
Analyze the physical processes behind coastal degradation phenomena.
Identify coastal inundation and aquifer salinization as marine saltwater intrusion driven by coastal erosion and groundwater depletion.
Estuarine environments and coastal aquifers suffer salinization primarily when hydraulic pressure drops from subterranean extraction alongside marine encroachment.
2
Evaluate agricultural soil degradation in semi-arid and arid irrigation schemes.
Link soil salinization to capillary action under high evapotranspiration rates where poor drainage prevents salt flushing.
Irrigation water contains dissolved minerals that accumulate at the surface as water evaporates, creating osmotic barriers for crops.
3
Examine atmospheric pollution hazards associated with oil extraction.
Associate gas flaring with chemical oxidation yielding acidic rainwater that degrades soil chemistry and built structures.
Flaring releases gaseous combustion byproducts (SO2SO_2 and NOxNO_x) that react with atmospheric water vapor.
4
Trace hydrologic landform degradation from watershed clearing to river deposition.
Connect headwater vegetation removal to concentrated gully incision and downstream reservoir siltation.
Removing forest canopy reduces rain interception and infiltration, accelerating overland flow into steep gullies that transport sediment into river basins.

Key Concept

Environmental Hazards, Degradation Mechanisms, and Ecological Management
Estimated Time:2m 0s
Question 211Question →

A meteorological station measures atmospheric moisture levels using two adjacent thermometers mounted together inside a Stevenson screen. Which instrument utilizes a dry bulb and a wet bulb covered in damp muslin to determine relative humidity?

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Answer: Wet-and-dry bulb psychrometer

Answer

Wet-and-dry bulb psychrometer
The wet-and-dry bulb psychrometer (hygrometer) measures atmospheric relative humidity by evaluating the difference between dry-bulb air temperature and wet-bulb temperature caused by evaporative cooling.

Step-by-Step Solution

1
Identify the weather parameter being measured in the question stem
The target weather parameter is relative humidity (atmospheric moisture).
The stem describes calculating atmospheric moisture levels using dry and wet bulb temperature readings.
2
Match the specified weather parameter and construction mechanism to the standard meteorological instrument
The wet-and-dry bulb psychrometer (a type of hygrometer) is the instrument designed with two thermometers to measure relative humidity.
Water evaporating from the wet muslin sleeve cools the wet-bulb thermometer, creating a depression that correlates directly with relative humidity.

Key Concept

Measurement of Relative Humidity using a Hygrometer/Psychrometer
Estimated Time:45s
Question 212Question →

On a humid tropical hillside, fence posts, terraced walls, and telephone poles are observed to tilt gradually downslope over several years without any sudden or catastrophic land movement. Which process is primarily responsible for this phenomenon?

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Answer: Soil creep

Answer

Soil creep is the process responsible for the gradual, imperceptible downslope tilting of structures on a hillside.
Soil creep is the slowest form of mass wasting. It operates imperceptibly over long periods, causing topsoil and embedded structures such as fence posts, trees, and telephone poles to tilt progressively in the direction of the slope.

Step-by-Step Solution

1
Identify the nature of the movement described in the scenario
The movement is extremely slow, continuous, and driven by gravity without sudden slope failure.
Gradual displacement of surface objects over years indicates slow mass wasting.
2
Differentiate mass wasting processes from weathering and deep geological processes
Soil creep specifically causes slow downslope displacement of topsoil and man-made structures like fence posts and poles.
In-situ weathering processes break down rocks without displacing them downslope.

Key Concept

Soil creep as a slow mass wasting mechanism
Estimated Time:1m 0s
Question 213Question →

Mass movement processes vary significantly in their mechanism and rate of downslope displacement under the influence of gravity. Arrange the following mass wasting processes in sequential order from the slowest rate of movement to the fastest rate of movement.

Drag items to arrange them in the correct order

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Answer

The correct sequence from slowest to fastest velocity is Soil Creep, followed by Solifluction, Rotational Slump, and Rockfall.
Mass wasting processes are classified by their velocity and movement mechanism. Soil creep is imperceptibly slow (millimeters/year). Solifluction is slow soil flow (centimeters to meters/year). Rotational slump represents moderate speed coherent rotational sliding along a curved rupture surface. Rockfall is the fastest process, featuring airborne free-fall at several meters per second.

Step-by-Step Solution

1
Identify the slowest form of mass wasting.
Soil creep is identified as the slowest process, measuring only millimeters per year.
Creep is driven by freeze-thaw or wetting-drying expansion/contraction cycles operating over extended periods.
2
Identify the slow-to-moderate flow process operating in saturated topsoil.
Solifluction follows soil creep as a slow downslope flow process.
Water saturation reduces friction in saturated regolith over impermeable substrate, causing slow flow measured in centimeters to meters annually.
3
Identify the moderate-speed sliding process.
Rotational slump comes next in velocity.
Slumping occurs along a defined curved slip plane, yielding faster displacement than soil creep or solifluction.
4
Identify the fastest mass movement process.
Rockfall is identified as the fastest mass wasting type.
Rockfall involves direct free-fall under gravity through air without basal friction, resulting in instantaneous, high-velocity movement.

Key Concept

Mass Wasting Rates of Movement
Question 214Question →

A geologist examining a rock specimen observes that it has a coarse-grained texture with large, visible mineral crystals of quartz and feldspar, indicating slow cooling deep beneath the Earth's surface. Which of the following rocks best matches this description?

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Answer: Granite

Answer

Granite is an intrusive igneous rock characterized by a coarse-grained crystalline texture formed through the slow cooling of molten magma beneath the Earth's surface.
Granite forms when magma cools slowly beneath the Earth's crust. This extended cooling period allows mineral crystals such as quartz and feldspar ample time to grow, producing a coarse-grained interlocking texture characteristic of plutonic igneous rocks.

Step-by-Step Solution

1
Analyze the structural texture and mineral composition described in the question stem.
The presence of large, visible crystals of quartz and feldspar indicates a coarse-grained, phaneritic texture.
Crystal size in igneous rocks is directly controlled by the cooling rate of molten material.
2
Determine the mode of origin based on the cooling rate.
Slow cooling occurs deep within the Earth's crust under high pressure (plutonic/intrusive origin).
Crustal insulation slows heat loss, allowing minerals sufficient time to grow well-defined crystals.
3
Match the cooling mode and mineral composition to the correct rock specimen.
Granite is the principal coarse-grained intrusive igneous rock composed mainly of quartz and orthoclase feldspar.
Extrusive rocks cool too rapidly to form coarse crystals, whereas sedimentary and metamorphic rocks develop through secondary surface or metamorphic processes.

Key Concept

Intrusive vs Extrusive Igneous Rock Textures and Origin
Question 215Question →

Match each meteorological instrument on the left with the atmospheric parameter it is designed to measure on the right.

Click a left item, then click its matching right item

Items

Anemometer
Hygrometer (Psychrometer)
Barometer
Campbell-Stokes Recorder

Matches

Show answer & explanation

Answer

Anemometer matches with Wind speed; Hygrometer (Psychrometer) matches with Relative humidity; Barometer matches with Atmospheric pressure; Campbell-Stokes Recorder matches with Duration of bright sunshine.
Each weather instrument is correctly matched with its specific target parameter: the anemometer measures wind speed, the hygrometer/psychrometer measures atmospheric moisture or relative humidity, the barometer measures air pressure, and the Campbell-Stokes recorder logs the duration of sunshine.

Step-by-Step Solution

1
Identify the primary function of each meteorological instrument listed on the left.
Anemometer = wind speed measure; Hygrometer = humidity measure; Barometer = pressure measure; Campbell-Stokes Recorder = sunshine duration measure.
Each instrument has a unique design targeted at recording a specific weather element.
2
Pair each instrument to its corresponding atmospheric parameter.
Match left_1 to right_4, left_2 to right_3, left_3 to right_2, and left_4 to right_1.
This establishes accurate instrument-parameter alignment without misattributing measurement functions.

Key Concept

Weather Instruments and Parameter Measurement
Question 216Question →

During upper-course fluvial erosion, rock fragments and coarse sediment carried by a river continuously grind against the riverbed and channel walls, scouring and wearing them down through mechanical friction. Which process of river erosion does this action describe?

Show answer & explanation

Answer: Corrasion

Answer

Corrasion (abrasion) is the process of river erosion where transported rock fragments grind against and wear down the riverbed and banks.
Corrasion, also known as mechanical abrasion, takes place when boulders, pebbles, and sand particles trapped in the river current scrape, scour, and wear down the bed and banks of the river channel.

Step-by-Step Solution

1
Analyze the mechanism described in the stem
The stem describes mechanical grinding of the riverbed and banks using the river's sediment load as an abrasive agent.
Identifying whether the process involves load-on-channel friction, load-on-load collisions, chemical solution, or fluid pressure isolates the correct geomorphic term.
2
Distinguish corrasion from other fluvial erosion processes
Corrasion (abrasion) uniquely refers to load wearing away channel boundaries, whereas attrition is load wearing load, corrosion is solvent dissolving rock, and hydraulic action is fluid force alone.
Matching the definition to official Senior Secondary School (SSS) geography terminology ensures correct classification.

Key Concept

Fluvial Erosion Processes (Corrasion, Attrition, Corrosion, Hydraulic Action)
Question 217Question →

As moist air masses ascend the windward slopes of a major mountain barrier, they cool adiabatically and deposit heavy precipitation. As the air descends on the opposite side, it warms adiabatically and absorbs moisture, resulting in arid or semi-arid conditions. Which climatic control and associated phenomenon are responsible for the dry climate on the leeward side?

Show answer & explanation

Answer: Relief acting as a climatic barrier to produce a rain-shadow zone

Answer

Relief acting as a climatic barrier to produce a rain-shadow zone
Relief serves as a major climatic control. When moist air encounters a mountain range, it is forced to ascend, cooling at the adiabatic lapse rate and releasing rain on the windward slope. Upon crossing the crest, the air descends the leeward side, warming adiabatically. This dry, warm descending air creates a dry belt known as a rain-shadow region.

Step-by-Step Solution

1
Analyze the physical process described in the stem
Air ascends windward slopes (orographic uplift), cools adiabatically, condenses, and precipitates, leaving dry air to descend the leeward slope.
Topography (relief) physically intercepts air masses.
2
Identify the climatic control and resultant feature
The climatic control is relief (orography) and the feature created on the sheltered leeward side is a rain-shadow zone.
Desiccated air warming adiabatically on the leeward side suppresses cloud formation and precipitation.

Key Concept

Relief and Orographic Rain-Shadow Effect
Question 218Question →

At a meteorological station in Jos, Nigeria, a weather observer records a maximum daily air temperature of 28.5∘C28.5^\circ\text{C} and a minimum daily air temperature of 17.5∘C17.5^\circ\text{C} using a Six's maximum and minimum thermometer. What is the mean daily temperature in ∘C^\circ\text{C}?

Show answer & explanation

Answer: 23

Answer

The mean daily temperature is 23.0∘C23.0^\circ\text{C}.
The mean daily temperature is determined by taking the average of the daily maximum and minimum temperatures: 28.5∘C+17.5∘C2=23.0∘C\frac{28.5^\circ\text{C} + 17.5^\circ\text{C}}{2} = 23.0^\circ\text{C}.

Step-by-Step Solution

1
Sum the maximum daily temperature and minimum daily temperature recorded at the weather station.
28.5∘C+17.5∘C=46.0∘C28.5^\circ\text{C} + 17.5^\circ\text{C} = 46.0^\circ\text{C}
Finding the total combined temperature extreme values is the first step in calculating the arithmetic mean.
2
Divide the combined total temperature by 2.
46.0∘C2=23.0∘C\frac{46.0^\circ\text{C}}{2} = 23.0^\circ\text{C}
The mean daily temperature represents the average temperature over a 24-hour observation period.

Key Concept

Calculation of Mean Daily Temperature
Estimated Time:45s
Question 219Question →

Along a steep rocky headland, storm waves repeatedly force air under extreme pressure into narrow joints and bedding planes at the back of a sea cave. As waves surge into the cave, the rapid trapped air compression followed by explosive expansion causes vertical disintegration of the roof until an opening reaches the cliff top surface above. Which of the following coastal landforms is formed by this specific process?

Show answer & explanation

Answer: Blowhole

Answer

Blowhole
The correct answer describes a blowhole. Hydraulic action occurs when sea waves rush into a sea cave, compressing air trapped in fissures in the cave roof. The repeated sudden pressure changes shatter the rock above, creating a vertical shaft that penetrates the cliff surface.

Step-by-Step Solution

1
Analyze the geomorphic process described in the stem.
The mechanism involves wave energy forcing trapped air under pressure into cave roof joints, causing vertical erosion upward through the cliff.
Air compression wedging (hydraulic action) inside sea caves acts vertically on weakness lines in the roof.
2
Identify the resulting coastal erosional landform.
Vertical breaching of a sea cave roof to the cliff top forms a shaft known as a blowhole (or gloup).
Continued upward hydraulic erosion creates a vertical vent through which sea spray is forced during high tide or heavy seas.
3
Differentiate from alternative landforms.
Fluvial features (oxbow lakes, deltaic channels) and subaerial mass wasting features (scree slopes) do not originate from coastal cave hydraulic erosion.
Oxbow lakes and deltas belong to river system deposition, while scree slopes arise from freeze-thaw weathering and slope failure.

Key Concept

Coastal erosional processes and sea cave landform development
Estimated Time:1m 30s
Question 220Question →

Match each Köppen climate classification symbol on the left with its primary controlling atmospheric mechanism and seasonal characteristics on the right.

Click a left item, then click its matching right item

Items

Af (Equatorial Climate)
BWh (Hot Desert Climate)
Cs (Mediterranean Climate)
ET (Tundra Climate)

Matches

Show answer & explanation

Answer

Af matches with high year-round rainfall and ITCZ influence; BWh matches with extreme aridity under subtropical highs; Cs matches with dry summers and wet westerly winters; ET matches with severe cold and warmest month below 10°C.
Each Köppen symbol maps directly to its controlling atmospheric mechanism: Af is controlled by low pressure at the ITCZ, BWh by subtropical anticyclones, Cs by seasonal migration of high pressure and westerly wind belts, and ET by polar air mass dominance at high latitudes.

Step-by-Step Solution

1
Analyze Af climate characteristics
Af represents a tropical wet climate with continuous high temperatures and rainfall governed by the ITCZ.
The 'f' suffix in Köppen classification denotes fully humid conditions without a dry season.
2
Analyze BWh climate controls
BWh indicates a hot arid desert climate created by atmospheric subsidence in subtropical high-pressure zones.
Subtropical high-pressure belts cause sinking air that inhibits condensation and cloud formation.
3
Analyze Cs climate controls
Cs denotes a Mediterranean climate with dry summers and wet winters resulting from latitudinal wind belt shifts.
Poleward shift of subtropical highs brings summer dryness, while equatorward shift of westerlies brings winter rains.
4
Analyze ET climate characteristics
ET represents a tundra climate where high latitudinal location suppresses summer warming above 10°C.
High-latitude location leads to low solar incidence angles and long, harsh polar winters.

Key Concept

Köppen Climate Classification and World Climatic Controls
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