All practice questions

Question 12701Question →

An environmental planning team in Nigeria is integrating multispectral satellite imagery with ground survey data in a Geographic Information System (GIS) to monitor vegetation health across the Guinea Savanna belt. When analyzing the reflectance values of healthy green crops, the sensor records high reflectance in the near-infrared (NIR) spectrum and high absorption in the red visible spectrum. Which fundamental remote sensing principle explains this specific spectral reflectance behavior?

Chlorophyll pigments absorb visible red light for photosynthesis while the internal mesophyll cell structure strongly scatters near-infrared energy.

Water molecules stored within plant leaves absorb near-infrared energy while transmitting red light through the canopy.

Bare soil background exposure amplifies red wavelengths while absorbing near-infrared solar radiation.

Thermal emissions from the canopy dominate the near-infrared band during peak daylight hours.

Show answer & explanation

Answer: Chlorophyll pigments absorb visible red light for photosynthesis while the internal mesophyll cell structure strongly scatters near-infrared energy.

Answer

Chlorophyll pigments absorb visible red light for photosynthesis while the internal mesophyll cell structure strongly scatters near-infrared energy.

The correct response accurately identifies that active leaf chlorophyll absorbs red visible light (around 0.66 µm) for energy conversion, while the refractive boundaries of healthy mesophyll cells reflect and scatter near-infrared radiation (0.7–1.1 µm). This sharp contrast creates the characteristic 'red edge' in vegetation spectral signatures.

Step-by-Step Solution

1

Identify the optical response of vegetation across different electromagnetic spectrum bands.

Healthy vegetation exhibits a distinct spectral signature characterized by low reflectance in the visible red region and high reflectance in the near-infrared region.

Plant physiological properties interact distinctly with specific wavelengths of solar radiation.

2

Analyze the biochemical cause of visible red light absorption.

Chlorophyll a and b inside leaf chloroplasts absorb blue and red light primary wavelengths for photosynthesis.

Absorbed photon energy drives photosynthetic chemical reactions.

3

Analyze the structural cause of near-infrared scattering.

The spongy mesophyll cellular structure inside leaves refracts and scatters up to 50% of incoming NIR radiation to prevent thermal overheating.

Unabsorbed NIR energy passes through cell wall interfaces and reflects outward toward satellite sensors.

Key Concept

Spectral Signatures of Land Cover Types in Remote Sensing

Estimated Time:1m 30s

Question 12702Question →

On a topographical map extract drawn at a scale of $1:50,000$ , the total length of all stream channels within a river basin is measured as $18\text{ cm}$ , while the total area of the basin on the map is $12\text{ cm}^2$ . What is the drainage density of this river basin in $\text{km/km}^2$ ?

Show answer & explanation

Answer: 3

Answer

The drainage density of the river basin is

3\text{ km/km}^2

.

Drainage density is determined by dividing total real stream length by total real area of the drainage basin. Given a map scale of

1:50,000

,

18\text{ cm}

of stream length translates to

9\text{ km}

, and

12\text{ cm}^2

of area translates to

3\text{ km}^2

. The resulting quotient gives a drainage density of

3\text{ km/km}^2

.

Step-by-Step Solution

1

Convert linear map measurement to actual distance in kilometers

18\text{ cm} \text{ on map} = 18 \times 0.5\text{ km} = 9\text{ km}

At a scale of

1:50,000

,

1\text{ cm}

represents

50,000\text{ cm}

or

0.5\text{ km}

on the ground.

2

Convert map area measurement to actual area in square kilometers

12\text{ cm}^2 \text{ on map} = 12 \times (0.5\text{ km})^2 = 12 \times 0.25\text{ km}^2 = 3\text{ km}^2

Area scale ratio is the square of the linear scale ratio (

(0.5\text{ km/cm})^2 = 0.25\text{ km}^2/\text{cm}^2

).

3

Calculate drainage density using the formula

D_d = \frac{\sum L}{A}

D_d = \frac{9\text{ km}}{3\text{ km}^2} = 3\text{ km/km}^2

Drainage density is defined as the total length of streams per unit drainage area.

Key Concept

Drainage Density and Scale Conversion

Estimated Time:1m 30s

Question 12703Question →

A thermocouple thermometer produces an electromotive force (e.m.f.) of $2.0\,\text{mV}$ at the ice point ( $0^\circ\text{C}$ ) and $18.0\,\text{mV}$ at the steam point ( $100^\circ\text{C}$ ). When placed in a liquid bath, the recorded e.m.f. is $14.0\,\text{mV}$ . What is the temperature of the liquid bath on the Celsius scale?

66.7^\circ\text{C}

70.0^\circ\text{C}

75.0^\circ\text{C}

87.5^\circ\text{C}

Show answer & explanation

Answer: $75.0^\circ\text{C}$

Answer

75.0^\circ\text{C}

The temperature on a linear scale is proportional to the fraction of the interval traversed between the fixed points. Subtracting the baseline reading of

2.0\,\text{mV}

gives an effective increase of

12.0\,\text{mV}

out of a total range of

16.0\,\text{mV}

. Multiplying this fraction (

0.75

) by

100^\circ\text{C}

yields

75.0^\circ\text{C}

.

Step-by-Step Solution

1

Identify the given thermometric values for the lower fixed point, upper fixed point, and unknown temperature reading.

E_0 = 2.0\,\text{mV}

,

E_{100} = 18.0\,\text{mV}

, and

E_\theta = 14.0\,\text{mV}

.

Linear temperature scales relate the change in thermometric property proportionally to temperature changes.

2

Apply the standard linear interpolation formula for a Celsius temperature scale.

\theta = \frac{E_\theta - E_0}{E_{100} - E_0} \times 100^\circ\text{C}

This accounts for the baseline reading at the ice point (

0^\circ\text{C}

) and normalizes it over the

100^\circ\text{C}

fundamental interval.

3

Substitute the known values and evaluate the expression.

\theta = \frac{14.0 - 2.0}{18.0 - 2.0} \times 100 = \frac{12.0}{16.0} \times 100 = 0.75 \times 100 = 75.0^\circ\text{C}

.

Carrying out the subtraction yields a proportional change of

\frac{3}{4}

of the full fundamental interval.

Key Concept

Temperature Scale Calibration and Thermocouple Interpolation

Estimated Time:1m 30s

Question 12704Question →

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

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 12705Question →

Match each African political division in Column A with its corresponding political-geographical characteristic in Column B.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Equatorial Guinea matches with having its capital on an offshore island separate from its mainland; Cabinda matches with being a political exclave of Angola separated by the Democratic Republic of the Congo; Eswatini matches with being a landlocked kingdom enclosed by South Africa and Mozambique; Seychelles matches with being an Indian Ocean island archipelago that is Africa's smallest sovereign country.

Each item in Column A correctly matches its distinct political-geographical status in Column B: Equatorial Guinea has its capital Malabo on Bioko Island separate from mainland Río Muni; Cabinda is an Angolan exclave separated by the Democratic Republic of the Congo; Eswatini is a landlocked kingdom enclosed by South Africa and Mozambique; and Seychelles is an Indian Ocean archipelago holding the distinction of being Africa's smallest sovereign nation.

Step-by-Step Solution

1

Analyze the territorial configuration of Equatorial Guinea

Equatorial Guinea consists of Bioko Island (where the capital Malabo is located) and the mainland region of Río Muni.

This makes it a unique political division where the national capital resides on an offshore island.

2

Examine the political status of Cabinda

Cabinda is an oil-rich province of Angola separated physically from Angola's main landmass by the Democratic Republic of the Congo's sea corridor.

A territory belonging to one country but geographically separated from it by another is defined as an exclave.

3

Identify the geographical position of Eswatini

Eswatini is a small landlocked country in Southern Africa surrounded by South Africa on three sides and Mozambique on its eastern border.

This establishes its exact political boundaries and landlocked nature.

4

Determine the territorial extent of Seychelles

Seychelles is an archipelago of 115 islands in the Indian Ocean covering a total land area of approximately 459 square kilometers.

It is recognized as Africa's smallest sovereign nation by both land size and population.

Key Concept

Spatial Layout, Boundaries, and Unique Political Divisions of African Nations

Question 12706Question →

Following severe coastal retreat along the Barrier-Lagoon coastline of Southwestern Nigeria, rigid concrete groynes were installed perpendicular to the shoreline. While sand accumulated on the up-drift side of the structures, beaches located further east experienced rapid sediment loss and accelerated landward erosion. What primary geomorphic process explains this unintended environmental hazard?

Interruption of the eastward longshore drift, which traps sediment on the up-drift side and starves down-drift coastlines of natural sand replenishment

Gravitational down-slope displacement of marine sediments triggered by localized mass wasting in mangrove mudflats

Displacement of the South-West Monsoon winds, which alters the local boundary between the rainforest and Guinea savanna zones

Reallocation of regulatory oversight from NOSDRA to NESREA, which delayed maintenance dredging operations

Show answer & explanation

Answer: Interruption of the eastward longshore drift, which traps sediment on the up-drift side and starves down-drift coastlines of natural sand replenishment

Answer

Interruption of the eastward longshore drift, which traps sediment on the up-drift side and starves down-drift coastlines of natural sand replenishment

Along the Barrier-Lagoon coast of Southwestern Nigeria (such as the Lagos shoreline), prevailing waves from the Atlantic Ocean approach obliquely, driving longshore drift from west to east. Constructing groynes perpendicular to the shore traps sand on the western (up-drift) side. Because the sediment supply moving down the coast is blocked, waves hitting the eastern (down-drift) side continue to carry sand away without receiving replenishment, resulting in severe accelerated coastal erosion.

Step-by-Step Solution

1

Analyze the coastal physical processes along the Southwestern coastline of Nigeria

Waves generated by the South-West Monsoon strike the coast at an oblique angle, creating a strong eastward littoral drift (longshore transport of sand).

Understanding the baseline sediment transport direction along the Nigerian coast is necessary to evaluate human intervention impacts.

2

Evaluate the structural impact of perpendicular groynes on littoral transport

Groynes act as barriers to longshore drift, causing deposition on the up-drift (western) side while preventing sand from reaching the down-drift (eastern) side.

Artificial barriers disrupt the sediment budget balance, causing downdrift beach starvation and accelerated erosion.

3

Select the option that accurately describes this coastal dynamics mechanism

The option identifying longshore drift interruption correctly explains the cause of downdrift erosion.

This directly links coastal engineering hazards with physical geography principles of wave action and sediment transport.

Key Concept

Coastal Erosion Hazards and Shoreline Management Dynamics in Nigeria

Estimated Time:2m 0s

Question 12707Question →

The rate of heat transfer through a uniform metallic rod of cross-sectional area $A$ and length $d$ is given by $\frac{Q}{t} = \frac{k A \Delta T}{d}$ , where $Q$ is heat energy, $t$ is time, $\Delta T$ is temperature difference, and $k$ is thermal conductivity. What is the dimensional formula for $k$ in terms of mass ( $M$ ), length ( $L$ ), time ( $T$ ), and temperature ( $\Theta$ )?

M L T^{-3} \Theta^{-1}

M L^2 T^{-3} \Theta^{-1}

M L T^{-2} \Theta^{-1}

M L^{-1} T^{-3} \Theta^{-1}

Show answer & explanation

Answer: $M L T^{-3} \Theta^{-1}$

Answer

The dimensional formula for thermal conductivity is

M L T^{-3} \Theta^{-1}

.

Expressing thermal conductivity explicitly gives

k = \frac{Q d}{A \Delta T t}

. Substituting fundamental dimensions yields

[k] = \frac{(M L^2 T^{-2})(L)}{(L^2)(\Theta)(T)} = M L T^{-3} \Theta^{-1}

. Thus, the dimensional formula

M L T^{-3} \Theta^{-1}

is correct.

Step-by-Step Solution

1

Make thermal conductivity

k

the subject of the formula.

k = \frac{Q d}{A \Delta T t}

Isolating

k

enables direct substitution of base dimensional quantities.

2

Substitute fundamental dimensions for each physical quantity.

[k] = \frac{[M L^2 T^{-2}][L]}{[L^2][\Theta][T]}

Heat energy

Q

has dimensions

[M L^2 T^{-2}]

, distance

d

is

[L]

, area

A

is

[L^2]

, temperature change

\Delta T

is

[\Theta]

, and time

t

is

[T]

.

3

Combine exponents for each fundamental dimension.

[k] = M^{1} L^{2+1-2} T^{-2-1} \Theta^{-1} = M L T^{-3} \Theta^{-1}

Applying exponent laws simplifies the expression to base units.

Key Concept

Dimensional Analysis of Physical Constants

Question 12708Question →

Match each African regional economic grouping listed in Column A with its defining economic characteristic or objective in Column B.

Click a left item, then click its matching right item

Show answer & explanation

Answer

CEMAC matches with the shared Central African CFA franc monetary union; COMESA matches with the trade bloc succeeding the Preferential Trade Area; SACU matches with the world's oldest operating customs union; AMU matches with the North African sub-regional organization.

Each economic community is correctly matched to its specific historical origin, geographic zone, or economic structure: CEMAC is a Central African monetary union sharing the CFA franc; COMESA evolved directly from the PTA; SACU is the world's oldest customs union (founded 1910); and AMU unites North African Maghreb states.

Step-by-Step Solution

1

Identify the primary sub-region and structural focus of CEMAC.

CEMAC operates in Central Africa and centers on a common currency zone using the Central African CFA franc.

Economic and monetary communities are characterized by unified monetary policy and currency sharing.

2

Identify the historical origin and scope of COMESA.

COMESA succeeded the Eastern and Southern African Preferential Trade Area (PTA).

Regional Integration evolution in Africa involved transforming PTAs into common markets.

3

Identify the historical distinction of SACU.

SACU is the oldest functioning customs union, sharing revenue among Southern African nations.

SACU dates back to 1910, making it unique in terms of historical longevity among trade blocs.

4

Identify the geographic jurisdiction of AMU.

AMU consists of North African Maghreb nations.

Maghreb geographic terminology specifically refers to the northwest region of Africa.

Key Concept

Structural characteristics, scope, and objectives of African Regional Economic Communities (RECs)

Question 12709Question →

At a regional agricultural exhibition, $150$ farmers registered their crop cultivation. $85$ farmers grow cassava ( $C$ ), $70$ grow maize ( $M$ ), and $60$ grow yam ( $Y$ ). $35$ farmers grow both cassava and maize, $25$ grow both maize and yam, and $30$ grow both cassava and yam. If $15$ farmers grow all three crops, how many farmers grow none of these three crops?

Show answer & explanation

Answer: 10

Answer

The number of farmers who grow none of the three crops is 10.

Using the Principle of Inclusion-Exclusion for three sets, the number of farmers growing at least one of cassava, maize, or yam is given by

85 + 70 + 60 - 35 - 25 - 30 + 15 = 140

. Since there are

150

farmers in total, the number of farmers who grow none of these three crops is

150 - 140 = 10

.

Step-by-Step Solution

1

Calculate the cardinality of the union of the three sets using the Principle of Inclusion-Exclusion.

|C \cup M \cup Y| = 85 + 70 + 60 - 35 - 25 - 30 + 15 = 140

Summing the three individual set counts overcounts elements in pairwise intersections, which must be subtracted. The central triple intersection is then added back because it was subtracted once too often.

2

Subtract the size of the union from the size of the universal set.

|(C \cup M \cup Y)'| = 150 - 140 = 10

The complement of the union represents the set of farmers outside all three crop categories.

Key Concept

Principle of Inclusion-Exclusion for Three Sets

Question 12710Question →

Given the matrices $M = \begin{pmatrix} 2 & -1 \\ 3 & 4 \end{pmatrix}$ and $N = \begin{pmatrix} 1 & 0 \\ 2 & 3 \end{pmatrix}$ , what is the determinant of the matrix product $MN$ ?

14

15

24

33

Show answer & explanation

Answer: 33

Answer

33

Using the property that the determinant of a product of matrices equals the product of their individual determinants,

\det(M) = (2)(4) - (-1)(3) = 11

and

\det(N) = (1)(3) - (0)(2) = 3

. Multiplying these gives

\det(MN) = 11 \times 3 = 33

.

Step-by-Step Solution

1

Calculate the determinant of matrix

M

\det(M) = (2)(4) - (-1)(3) = 8 + 3 = 11

The determinant of a

2 \times 2

matrix

\begin{pmatrix} a & b \\ c & d \end{pmatrix}

is given by

ad - bc

.

2

Calculate the determinant of matrix

N

\det(N) = (1)(3) - (0)(2) = 3 - 0 = 3

Apply the determinant formula

ad - bc

to matrix

N

.

3

Apply the determinant product property to find

\det(MN)

\det(MN) = \det(M) \times \det(N) = 11 \times 3 = 33

For any two square matrices of the same order,

\det(MN) = \det(M) \cdot \det(N)

.

Key Concept

Determinant Property of Matrix Products

Estimated Time:1m 30s

Question 12711Question →

Environmental degradation in Nigeria exhibits distinct spatial patterns across its ecological zones. While the southeastern scarp lands of Anambra and Imo experience severe gully erosion driven by friable sedimentary formations and intense torrential rainfall, the low-lying Atlantic coastline of Lagos and the Niger Delta suffers from coastal surge flooding and rapid shoreline retreat. Which of the following resource management measures offers the most structurally effective long-term defense against coastal erosion and beach loss along Nigeria's Atlantic shorelines?

Establishing dense shelterbelt belts of drought-resistant Acacia and Eucalyptus species along the littoral margin.

Constructing heavy coastal engineering structures such as groynes, seawalls, and artificial beach nourishment.

Mandating targeted oil spill remediation procedures under the statutory enforcement scope of NESREA.

Practicing contour ploughing and slope terracing along littoral agricultural land gradients.

Show answer & explanation

Answer: Constructing heavy coastal engineering structures such as groynes, seawalls, and artificial beach nourishment.

Answer

Constructing heavy coastal engineering structures such as groynes, seawalls, and artificial beach nourishment.

The correct answer emphasizes direct physical coastal engineering interventions (groynes, seawalls, breakwaters, and beach nourishment). Coastal erosion along Nigeria's Atlantic coastline (such as the Bar Beach and Lekki coastal areas in Lagos) is driven by persistent high-energy wave action, ocean tides, and longshore drift. Installing groynes traps moving sand along the beach, seawalls shield coastal property from wave impact, and replenishment restores eroded shoreline buffers.

Step-by-Step Solution

1

Analyze the spatial hazard type and geographical setting presented in the stem.

The hazard is marine coastal erosion and shoreline retreat along Nigeria's southern Atlantic coastline (Lagos and Niger Delta).

Different ecological zones in Nigeria require hazard management tailored specifically to the dominant destructive forces operating in those environments.

2

Evaluate the coastal mechanics driving beach loss and marine inundation.

Marine shoreline erosion is driven by high-energy ocean wave action, longshore drift, tidal surges, and coastal land subsidence.

Mitigation measures must directly counteract or dissipate marine kinetic energy and stabilize littoral sediment movement.

3

Assess candidate management strategies for coastal engineering suitability.

Groynes trap littoral sediment along the shore, sea walls act as hard barriers reflecting storm wave energy, and artificial nourishment restores lost beach material.

Hard coastal protection structures combined with soft nourishment constitute the standard engineering response to marine coastal recession.

Key Concept

Spatial Zonation of Environmental Hazards and Targeted Management Strategies in Nigeria

Question 12712Question →

Match each statistical mapping technique listed on the left with the specific spatial phenomenon or cartographic data representation it is best suited to display on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Choropleth mapping pairs with density ratios displayed within predefined administrative unit boundaries. Dot distribution mapping pairs with absolute population numbers or livestock distributions using fixed quantitative point symbols. Isopleth mapping pairs with continuous spatial phenomena such as mean annual precipitation or temperature gradients. Flow line mapping pairs with volume, direction, and movement routes of international trade cargo or passenger traffic.

Choropleth mapping is designed for administrative ratio data; dot distribution mapping visually renders absolute discrete counts; isopleth mapping connects lines of equal continuous values; and flow line mapping depicts direction and volume of movement along transport routes.

Step-by-Step Solution

1

Identify the data characteristic of Choropleth mapping.

It relies on spatial units (states/districts) to display derived ratios/densities via shading.

Administrative boundary categorization is the defining feature of choropleth technique.

2

Identify the data characteristic of Dot distribution mapping.

It uses dots representing absolute quantities (e.g., 1 dot = 1,000 cattle) to depict spatial density.

Point-based quantitative representations accurately show spatial clustering of discrete counts.

3

Identify the data characteristic of Isopleth mapping.

It connects points of equal value over continuous surfaces like atmospheric pressure, elevation, or temperature.

Isopleths require smooth, continuous spatial data distributions rather than abrupt administrative boundaries.

4

Identify the data characteristic of Flow line mapping.

It represents linear movements with line width scaled to movement volume.

Flow lines are specialized for network movement and transportation dynamics.

Key Concept

Selection of Statistical Maps and Graphical Representation Methods

Question 12713Question →

In Nigeria's industrial sector, soft drink bottling facilities and brewery plants are widely distributed across major urban centers nationwide rather than concentrated in specific raw material regions. Which of the following primary industrial location factors accounts for this spatial distribution pattern?

The industries process bulk weight-losing raw materials that undergo significant weight reduction during manufacturing.

The manufacturing process yields weight-gaining, bulky, and fragile finished goods, making market proximity essential.

The industrial plants require direct location near coal deposits for thermal power generation during processing.

The raw inputs for brewing are exclusively grown in humid rainforest zones, restricting factories to southern regions.

Show answer & explanation

Answer: The manufacturing process yields weight-gaining, bulky, and fragile finished goods, making market proximity essential.

Answer

Beverage production is a market-oriented industry because processing adds substantial weight and bulk (water) to lightweight raw inputs, making market proximity the key factor to minimize distribution costs.

Beverage production (soft drinks and brewing) is a classic market-oriented industry. The manufacturing process incorporates large volumes of water locally available in urban areas, making the final product significantly heavier, bulkier, and more costly to transport than the initial raw ingredients. Siting plants close to high-density consumer markets across major Nigerian cities minimizes final distribution expenses.

Step-by-Step Solution

1

Analyze the nature of raw materials versus finished products in beverage manufacturing.

Main raw inputs (syrup, malt, concentrate) are compact, but processing adds large volumes of water, significantly increasing finished product weight and volume.

According to industrial location theory (Alfred Weber's least-cost location model), weight-gaining processes pull factory locations toward final consumer markets.

2

Evaluate transport economics for finished beverage distribution in urban Nigeria.

Transporting liquid-filled bottles and cans over long distances incurs higher freight costs and risks breakage compared to transporting raw concentrates.

Placing bottling and brewing facilities in large urban population hubs minimizes overall transport and distribution costs.

Key Concept

Market-Oriented Industrial Location Factors

Question 12714Question →

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?

Corrasion

Attrition

Corrosion

Hydraulic action

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 12715Question →

Match each environmental hazard occurring in Nigerian regions with its primary anthropogenic driving factor.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Urban flash flooding in Lagos matches with drainage blockage by waste and structures; Accelerated gully incision in Anambra matches with vegetation clearing and improper road drainage outlets; Marine ecosystem degradation in the Niger Delta matches with crude oil spillage and effluent discharge; Agricultural topsoil erosion matches with intensive tillage, overgrazing, and removal of ground cover.

Each hazard correctly aligns with its characteristic regional trigger in Nigeria: Lagos flooding is driven by blocked drainage; Anambra gully formation is driven by land clearing and unchanneled road runoff; Niger Delta aquatic damage is caused by oil spills and effluents; and savanna soil degradation is caused by overgrazing and intensive soil tillage.

Step-by-Step Solution

1

Identify the main human triggers of urban flash flooding in coastal mega-cities like Lagos.

High-density urbanization combined with improper waste disposal clogs drainage channels, causing water retention during rainstorm events.

Inadequate municipal drainage infrastructure causes rapid surface water pooling.

2

Examine the specific engineering and land-use factors driving gully erosion in southeastern Nigeria.

Unplanned road gutters direct concentrated runoff onto fragile, easily eroded soil strata in states such as Anambra.

Concentrated high-velocity runoff cuts rapidly into unprotected subsoils.

3

Analyze the primary causes of water pollution and aquatic loss in petroleum-producing areas.

Oil spills from hydrocarbon extraction and industrial discharges pollute creeks, killing aquatic life and damaging wetlands.

Chemical and oil contamination directly destroys marine biological life.

4

Relate farming practices to soil degradation in open savanna environments.

Overgrazing and clearing vegetative residue leave exposed surface soil vulnerable to raindrop impact and sheet wash.

Ground cover removal exposes topsoil to severe kinetic erosion by rainfall.

Key Concept

Human activities as driving forces of regional environmental hazards

Question 12716Question →

A poultry farmer in Ogun State took a loan of $\text{₦}120,000$ from a cooperative society at an annual interest rate of $5\%$ , compounded annually. What is the total interest paid by the farmer at the end of $2$ years?

\text{₦}12,300

\text{₦}132,300

\text{₦}12,000

\text{₦}132,000

Show answer & explanation

Answer: $\text{₦}12,300$

Answer

The total compound interest paid at the end of 2 years is

\text{₦}12,300

.

The total compound interest is determined by calculating the accumulated amount

A = 120,000 \times (1.05)^2 = \text{₦}132,300

and subtracting the original principal of

\text{₦}120,000

, yielding

\text{₦}12,300

.

Step-by-Step Solution

1

Identify the given values for principal, rate, and time

Principal

P = \text{₦}120,000

, Rate

r = 5\% = 0.05

, Time

t = 2\text{ years}

These parameters are required to substitute into the compound amount formula.

2

Calculate the total accumulated amount

A

after 2 years

A = P(1 + r)^t = 120,000 \times (1 + 0.05)^2 = 120,000 \times 1.1025 = \text{₦}132,300

The compound interest formula yields the total balance including the initial principal.

3

Subtract the initial principal from the total accumulated amount to determine interest

Compound Interest

= A - P = 132,300 - 120,000 = \text{₦}12,300

Interest is the extra amount generated beyond the original loan amount.

Key Concept

Compound Interest vs Total Accumulated Amount

Estimated Time:1m 30s

Question 12717Question →

In a Nigerian chemical manufacturing plant producing soap from local palm oil, arrange the key industrial stages in the correct sequential order from raw material preparation to the final finished product.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence begins with heating raw palm oil with concentrated sodium hydroxide solution, followed by boiling to complete saponification into soap and glycerol, then adding concentrated sodium chloride solution for salting out, and lastly washing, blending, and molding into finished soap bars.

The industrial manufacturing of soap follows a logical chemical sequence: raw oil is first combined with concentrated

NaOH

and heated; boiling carries out the saponification reaction producing soap and glycerol; adding brine (

NaCl

) decreases soap solubility to precipitate it (salting out); and finally, downstream refining, washing, perfuming, and molding produce marketable bars.

Step-by-Step Solution

1

Identify raw material mixing

Heating palm oil (triglycerides) with caustic soda (

NaOH

) prepares the reactants.

Chemical reactions require proper mixing and thermal energy to initiate saponification.

2

Perform the core chemical reaction

Boiling hydrolyzes triglycerides into sodium carboxylates (soap) and propane-1,2,3-triol (glycerol).

The fundamental chemical transformation occurs during this boiling stage.

3

Separate the product using electrolyte addition

Adding brine (

NaCl

) precipitates the soap curd by common-ion effect/salting out.

Soap is insoluble in concentrated salt solution, separating it cleanly from liquid glycerol.

4

Finish downstream processing

The crude soap is purified, blended with additives, and molded into market bars.

Commercial viability requires washing excess alkali, adding fragrance, and shaping.

Key Concept

Saponification process and salting out in soap manufacturing

Question 12718Question →

A field surveyor needs to determine the horizontal distance between two stations located on steeply sloping ground using a steel measuring tape and a plumb bob via the direct stepping method. Arrange the following field procedure steps in the correct chronological order from start to finish.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct procedural order is: (1) Insert ranging poles at both stations to establish the line, (2) Hold the tape zero mark at the upper station and extend the tape horizontally, (3) Suspend a plumb bob from the tape end to transfer the point vertically down, (4) Pin an arrow at the plumb bob tip on the ground, and (5) Advance down the slope repeating the steps progressively.

The stepping method requires first establishing a straight line between the stations using ranging poles. Next, short horizontal segments are extended from the higher elevation toward the lower elevation. A plumb bob is suspended from the elevated end of the horizontal tape to transfer the point vertically to the ground surface, where an arrow is pinned. The team then advances to repeat this sequence progressively down the slope.

Step-by-Step Solution

1

Establish the baseline path between stations.

Ranging poles fixed at both higher and lower stations line up the direction of measurement.

Clear line alignment prevents off-line measurement errors.

2

Stretch the tape horizontally from the upper station.

The tape forms a horizontal segment over the sloping terrain.

The direct horizontal stepping method requires holding convenient short lengths of tape parallel to the horizontal plane.

3

Use a plumb bob to project the tape mark to the slope surface.

The vertical projection point on the sloping ground is identified.

A plumb bob ensures true vertical transfer under the influence of gravity.

4

Mark the transferred ground position.

An arrow is inserted at the plumb bob tip.

This establishes a reliable temporary station for the next measurement interval.

5

Advance continuously down the slope.

Subsequent horizontal sections are measured and summed.

Accumulating the individual horizontal step lengths gives the exact horizontal distance between the end stations.

Key Concept

Direct Stepping Method on Sloping Ground

Question 12719Question →

A proposed industrial estate is represented as a square measuring $6\text{ cm}$ by $6\text{ cm}$ on a topographical map drawn to a scale of $1 : 40,000$ . If the map is reduced to a scale of $1 : 120,000$ , what is the new area of the industrial estate on the reduced map?

4\text{ cm}^2

12\text{ cm}^2

108\text{ cm}^2

324\text{ cm}^2

Show answer & explanation

Answer: $4\text{ cm}^2$

Answer

The new area of the industrial estate on the reduced map is

4\text{ cm}^2

.

When a map is reduced from a scale of

1:40,000

to

1:120,000

, the linear dimensions are reduced by a factor of

\frac{40,000}{120,000} = \frac{1}{3}

. Since area is two-dimensional, the area changes by the square of the linear ratio:

\left(\frac{1}{3}\right)^2 = \frac{1}{9}

. Multiplying the original area of

36\text{ cm}^2

by

\frac{1}{9}

gives

4\text{ cm}^2

.

Step-by-Step Solution

1

Calculate the original area of the feature on the map.

Original area =

6\text{ cm} \times 6\text{ cm} = 36\text{ cm}^2

.

The feature is rectangular/square, so area on map is length multiplied by width.

2

Determine the linear scale change ratio.

Linear scale factor =

\frac{\text{Old Scale Denominator}}{\text{New Scale Denominator}} = \frac{40,000}{120,000} = \frac{1}{3}

.

Changing scale from

1:40,000

to

1:120,000

reduces all linear dimensions to

1/3

of their original size.

3

Calculate the area scale factor and final area.

Area scale factor =

\left(\frac{1}{3}\right)^2 = \frac{1}{9}

. New Area =

36\text{ cm}^2 \times \frac{1}{9} = 4\text{ cm}^2

.

Areal change is proportional to the square of the linear scale ratio.

Key Concept

Relationship between linear scale ratio and area change in map reduction

Estimated Time:1m 30s

Question 12720Question →

Which environmental hazard is most prevalent in the low-lying coastal states of southern Nigeria, such as Lagos and Bayelsa, primarily driven by ocean surges and heavy seasonal rainfall?

Coastal flooding

Desert encroachment

Severe wind erosion

Frost damage

Show answer & explanation

Answer: Coastal flooding

Answer

Coastal flooding

Low-lying southern coastal states such as Lagos, Bayelsa, and Rivers are adjacent to the Atlantic Ocean. High tidal surges combined with heavy equatorial monsoon rainfall make coastal flooding the dominant environmental hazard in these areas.

Step-by-Step Solution

1

Identify the geographical region specified in the stem

The region covers low-lying coastal states in southern Nigeria, including Lagos and Bayelsa.

Geographical location determines the climatic and physical conditions driving specific environmental hazards.

2

Match the environmental hazard to coastal processes and climate

Heavy rainfall, high ocean surges, and low land elevation lead directly to coastal inundation and land loss.

Coastal flooding is the primary hazard affecting low-lying maritime territories in Nigeria.

Key Concept

Spatial distribution of environmental hazards in Nigeria

Answer

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