All practice questions

Question 13781Question →

A regional transport network connects $5$ agricultural collection hubs ( $v = 5$ ) using $7$ primary road segments ( $e = 7$ ) in a single connected network ( $p = 1$ ). What is the Alpha index ( $\alpha$ ) of this network graph?

0.60

1.40

0.40

0.71

Show answer & explanation

Answer: $0.60$

Answer

The Alpha index of the transport network is

0.60

.

The correct answer is

0.60

. The Alpha index evaluates circuit redundancy in a network graph using the formula

\alpha = \frac{e - v + p}{2v - 5}

. Substituting

e = 7

,

v = 5

, and

p = 1

yields

\frac{7 - 5 + 1}{2(5) - 5} = \frac{3}{5} = 0.60

.

Step-by-Step Solution

1

Calculate the actual number of fundamental circuits (

u

) present in the network using

u = e - v + p

.

u = 7 - 5 + 1 = 3

circuits.

The cyclomatic number

u

measures the actual redundancy (number of closed loops) in a network graph.

2

Calculate the maximum possible number of circuits in a planar graph with

v = 5

using

2v - 5

.

Maximum circuits

= 2(5) - 5 = 5

.

In planar network topology, the maximum theoretical number of circuits for

v

vertices is

2v - 5

.

3

Calculate the Alpha index (

\alpha

) by dividing the actual circuits by the maximum possible circuits.

\alpha = \frac{u}{2v - 5} = \frac{3}{5} = 0.60

.

The Alpha index measures network connectivity as a ratio between

0

(tree network with no circuits) and

1

(fully connected planar network).

Key Concept

Alpha Index of Network Connectivity

Alternative Method

Calculate the cyclomatic number

u = 7 - 5 + 1 = 3

. Then express

u

as a percentage of the maximum possible planar circuits

2(5) - 5 = 5

, giving

3/5 = 60\% = 0.60

.

Estimated Time:1m 15s

Question 13782Question →

In West Africa, nomadic pastoralism is extensively practiced in the northern savanna regions rather than the humid southern forest belt. Which factor primarily restricts large-scale cattle rearing in the southern forest zone?

Prevalence of tsetse flies carrying animal trypanosomiasis (nagana) in humid forest vegetation

High concentration of coastal linear settlement patterns that restrict grazing land expansion

Extensive cultivation of drought-resistant northern cash crops like groundnut and cotton in southern soils

Reversal of regional vegetation zones placing arid Sahel grassland pasture along the Atlantic coast

Show answer & explanation

Answer: Prevalence of tsetse flies carrying animal trypanosomiasis (nagana) in humid forest vegetation

Answer

Prevalence of tsetse flies carrying animal trypanosomiasis (nagana) in humid forest vegetation

The correct answer identifies the primary biological and environmental constraint: dense humid forest vegetation in southern West Africa supports populations of tsetse flies, which transmit animal trypanosomiasis (nagana). This disease causes high mortality among cattle, restricting nomadic pastoralism mainly to the drier northern savannas.

Step-by-Step Solution

1

Analyze the environmental requirements and biological constraints of pastoral cattle farming in West Africa.

Cattle thrive in open savanna grasslands with low vector infestation and abundant pasture.

Dense rainforest vegetation creates humid microclimates that host disease vectors harmful to livestock.

2

Identify the vector specific to humid forest environments in southern West Africa.

The tsetse fly transmits trypanosomiasis (nagana), causing high mortality in non-resistant cattle breeds.

This biological barrier naturally restricts pastoral pastoralism to the drier northern savanna zones where tsetse fly density is minimal.

Key Concept

Environmental constraints on pastoral farming systems

Question 13783Question →

A rectangular metallic sheet with a linear expansivity of $1.8 \times 10^{-5}\text{ K}^{-1}$ experiences a temperature rise of $50\text{ K}$ . If the increase in its surface area is $0.90\text{ cm}^2$ , what was the initial surface area of the sheet in $\text{cm}^2$ ?

Show answer & explanation

Answer: 500

Answer

The initial surface area of the metallic sheet is

500\text{ cm}^2

.

The initial area is found by converting linear expansivity to area expansivity (\beta = 2\alpha = 3.6 \times 10^{-5}\text{ K}^{-1}) and substituting into the area expansion relation \Delta A = A_0 \beta \Delta T, giving A_0 = \frac{0.90}{3.6 \times 10^{-5} \times 50} = 500\text{ cm}^2$.

Step-by-Step Solution

1

Calculate the area (superficial) expansivity (\beta)

\beta = 2\alpha = 2 \times 1.8 \times 10^{-5}\text{ K}^{-1} = 3.6 \times 10^{-5}\text{ K}^{-1}

Surface area expansion depends on area expansivity, which is twice the linear expansivity for an isotropic solid.

2

Formulate the thermal area expansion equation

\Delta A = A_0 \beta \Delta T

The fractional change in area is directly proportional to the area expansivity and the temperature change.

3

Rearrange the formula to solve for the initial surface area (A_0)

A_0 = \frac{\Delta A}{\beta \Delta T}

Isolating the required unknown quantity.

4

Substitute the known numerical values and compute

A_0 = \frac{0.90\text{ cm}^2}{(3.6 \times 10^{-5}\text{ K}^{-1})(50\text{ K})} = \frac{0.90}{1.8 \times 10^{-3}} = 500\text{ cm}^2

Evaluating the expression yields the exact initial surface area.

Key Concept

Relationship between Linear Expansivity and Area Expansivity

Alternative Method

Calculate fractional area expansion per kelvin: \beta = 2\alpha = 3.6 \times 10^{-5}\text{ K}^{-1}

. Total fractional expansion for

50\text{ K}

is

3.6 \times 10^{-5} \times 50 = 0.0018

. Then initial area

A_0 = \frac{0.90}{0.0018} = 500\text{ cm}^2$.

Estimated Time:1m 30s

Question 13784Question →

In a standard Coolidge X-ray tube, more than 90% of the kinetic energy of the fast-moving electrons striking the target anode is converted directly into X-rays.

True

False

Show answer & explanation

Answer: False

Answer

False

The assertion is false because X-ray generation is a highly inefficient physical process. Less than 1% of the kinetic energy possessed by the high-speed electrons striking the target is converted into X-radiation. More than 99% of the kinetic energy is converted into heat, necessitating target materials with very high melting points (such as tungsten) embeddded in copper blocks for rapid heat conduction.

Step-by-Step Solution

1

Examine the energy transformation process during X-ray generation in a Coolidge tube.

Accelerated electrons collide with the heavy metal target anode, undergoing inelastic scattering and atomic interactions.

Electrons lose kinetic energy rapidly upon impact with the target material.

2

Evaluate the energy conversion ratio between radiation and heat.

Only approximately 0.2% to 1% of the total electron kinetic energy produces X-ray radiation (both Bremsstrahlung and characteristic emissions). The remaining 99%+ is converted into heat.

Most electron impacts only excite outer electron shells and cause lattice vibrations (thermal agitation) rather than inner-shell ionization or violent retardation.

Key Concept

Efficiency of X-ray production and heat generation at the target anode

Estimated Time:45s

Question 13785Question →

Consider the economic operations involved in transforming raw natural resources into finished consumer goods within the Nigerian commercial sector. Arrange the following economic activities in the correct chronological sequence to illustrate how raw rubber moves through industry, commerce, and occupation from extraction to final usage.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological sequence is: Tapping and extracting raw latex fluid from rubber trees on a plantation, followed by Processing latex into vulcanized rubber and manufacturing automobile tires in an industrial plant, then Insuring and storing bulk consignments of finished tires in commercial warehouses, and finally Selling individual tires to end-user motorists through retail motor spare-parts traders.

The correct sequence demonstrates how economic activities integrate: primary industry extracts raw latex, secondary industry manufactures tires, auxiliaries to trade store and insure stock, and retail trade distributes finished goods to final consumers.

Step-by-Step Solution

1

Identify the primary extractive occupation and industry activity

Tapping and extracting raw latex fluid from rubber plantations represents the primary industry stage.

Primary industry must occur first to provide raw material inputs.

2

Identify the secondary manufacturing industry activity

Processing latex into vulcanized rubber and manufacturing automobile tires represents the manufacturing stage.

Secondary manufacturing transforms primary raw materials into usable manufactured goods.

3

Identify the commercial auxiliary service activity

Insuring and storing bulk consignments in commercial warehouses represents the auxiliary to trade stage.

Commercial support services take place to protect, store, and prepare products before retail distribution.

4

Identify the commercial trade and retail occupation activity

Selling individual tires to end-user motorists through retail motor spare-parts traders represents the trade stage.

Retailing completes the economic chain by making goods available to final consumers.

Key Concept

Inter-relationship Between Industry, Commerce, and Occupation in the Chain of Production

Question 13786Question →

A trolley P of mass $4.0\text{ kg}$ moving due east at $5.0\text{ m s}^{-1}$ collides head-on with a trolley Q of mass $1.0\text{ kg}$ moving due west at $10.0\text{ m s}^{-1}$ . If the two trolleys coalesce upon impact, what is their common velocity?

2.0\text{ m s}^{-1}

due east

6.0\text{ m s}^{-1}

due east

2.5\text{ m s}^{-1}

due east

1.0\text{ m s}^{-1}

due east

Show answer & explanation

Answer: $2.0\text{ m s}^{-1}$ due east

Answer

2.0\text{ m s}^{-1}

due east

Linear momentum is conserved in an isolated system. Taking east as positive, the initial momentum of trolley P is

+20.0\text{ kg m s}^{-1}

and trolley Q is

-10.0\text{ kg m s}^{-1}

, yielding a net initial momentum of

+10.0\text{ kg m s}^{-1}

. After impact, the total mass is

4.0\text{ kg} + 1.0\text{ kg} = 5.0\text{ kg}

. The common velocity is

\frac{10.0}{5.0} = +2.0\text{ m s}^{-1}

, where the positive sign denotes a direction due east.

Step-by-Step Solution

1

Assign a directional coordinate system

Let the eastward direction be positive (

+

) and the westward direction be negative (

-

)

Linear momentum is a vector quantity, so opposite directions must have opposite signs.

2

Calculate total initial momentum (

p_i

)

p_i = m_P u_P + m_Q u_Q = (4.0 \times 5.0) + (1.0 \times (-10.0)) = 20.0 - 10.0 = +10.0\text{ kg m s}^{-1}

According to the principle of conservation of linear momentum, initial momentum equals final momentum.

3

Calculate final common velocity (

v

)

v = \frac{p_i}{m_P + m_Q} = \frac{+10.0}{4.0 + 1.0} = +2.0\text{ m s}^{-1}

Since the trolleys coalesce, they move together with a total combined mass of

5.0\text{ kg}

.

Key Concept

Conservation of Linear Momentum in 1D Inelastic Collisions

Question 13787Question →

A business enterprise in Rivers State engages in three sequential operations: drilling crude oil from offshore wells, refining the crude oil into premium motor spirit (PMS), and purchasing marine insurance for the export shipment. Which of the following correctly categorizes these three activities into their respective occupational classifications?

Primary occupation, secondary occupation, and tertiary (commercial service) occupation

Primary occupation, secondary occupation, and tertiary (direct service) occupation

Secondary (extractive) occupation, secondary (manufacturing) occupation, and tertiary (commercial service) occupation

Primary occupation, primary occupation, and secondary occupation

Show answer & explanation

Answer: Primary occupation, secondary occupation, and tertiary (commercial service) occupation

Answer

Primary occupation, secondary occupation, and tertiary (commercial service) occupation

Drilling crude oil extracts raw natural wealth from the environment, which defines a primary occupation. Processing crude oil into refined petroleum products alters the physical form of the raw material into a usable product, defining a secondary manufacturing occupation. Marine insurance provides risk mitigation to facilitate commercial trade transactions, which classifies it as an auxiliary to trade within tertiary commercial services.

Step-by-Step Solution

1

Classify the first activity: drilling crude oil from offshore wells.

Primary occupation (extractive industry, collecting gifts of nature).

Extraction of natural resources directly from nature forms the primary sector of occupation.

2

Classify the second activity: refining crude oil into premium motor spirit (PMS).

Secondary occupation (manufacturing/processing industry).

Transforming raw materials into semi-finished or finished usable products constitutes secondary occupation.

3

Classify the third activity: purchasing marine insurance for the export shipment.

Tertiary (commercial service / auxiliary to trade) occupation.

Insurance aids trade by bearing risks involved in moving goods, placing it under commercial tertiary services.

Key Concept

Classification of occupations into primary (extractive), secondary (manufacturing/construction), and tertiary (commercial vs direct services).

Estimated Time:1m 0s

Question 13788Question →

On a topographical map drawn to a scale of $1 : 30,000$ , a straight-line distance of $10\text{ cm}$ is measured along a hillside track connecting a radio mast at an elevation of $480\text{ m}$ to a valley bridge at an elevation of $180\text{ m}$ . What is the gradient of the slope between the radio mast and the valley bridge?

1 \text{ in } 10

1 \text{ in } 100

1 \text{ in } 6.25

1 \text{ in } 3

Show answer & explanation

Answer: $1 \text{ in } 10$

Answer

The gradient of the slope is

1 \text{ in } 10

.

The slope gradient is defined as the ratio of Vertical Interval (VI) to Horizontal Equivalent (HE). The vertical rise between the radio mast (

480\text{ m}

) and the bridge (

180\text{ m}

) is

300\text{ m}

. The actual ground distance represented by

10\text{ cm}

on a

1 : 30,000

scale map is

10 \times 30,000\text{ cm} = 300,000\text{ cm} = 3,000\text{ m}

. Dividing the vertical rise by the horizontal distance gives

\frac{300}{3000} = \frac{1}{10}

, expressed as a ratio of

1 \text{ in } 10

.

Step-by-Step Solution

1

Calculate the Vertical Interval (VI)

\text{VI} = 480\text{ m} - 180\text{ m} = 300\text{ m}

Vertical Interval is the difference in height between the highest point and the lowest point.

2

Calculate the Horizontal Equivalent (HE) in ground units (meters)

\text{Ground Distance} = 10\text{ cm} \times 30,000 = 300,000\text{ cm} = 3,000\text{ m}

Multiply map distance by the scale factor and convert from centimeters to meters.

3

Compute the gradient ratio

\text{Gradient} = \frac{\text{VI}}{\text{HE}} = \frac{300\text{ m}}{3,000\text{ m}} = \frac{1}{10} = 1 \text{ in } 10

Gradient is expressed as the ratio of Vertical Interval to Horizontal Equivalent in identical units.

Key Concept

Slope and Gradient Calculation

Estimated Time:1m 30s

Question 13789Question →

A hiker walks $12\text{ km}$ due East, then $9\text{ km}$ due South, and finally $4\text{ km}$ due North. What is the magnitude of the hiker's total displacement from the starting point?

13\text{ km}

25\text{ km}

15\text{ km}

7\text{ km}

Show answer & explanation

Answer: $13\text{ km}$

Answer

The magnitude of the hiker's total displacement is

13\text{ km}

.

Displacement is a vector quantity requiring directional vector addition. The horizontal Eastward component is

12\text{ km}

. The net vertical component along the North-South line is

9\text{ km \text{ South}} - 4\text{ km \text{ North}} = 5\text{ km \text{ South}}

. Because the East and South directions are perpendicular (

90^\circ

), the resultant displacement magnitude is

\sqrt{12^2 + 5^2} = \sqrt{169} = 13\text{ km}

.

Step-by-Step Solution

1

Set up a coordinate system for horizontal (East-West) and vertical (North-South) components.

East is

+x

direction and North is

+y

direction.

Resolving vectors into orthogonal components allows simple independent summation along each axis.

2

Calculate net displacement along the x-axis and y-axis.

R_x = +12\text{ km}

and

R_y = -9\text{ km} + 4\text{ km} = -5\text{ km}

.

North and South act in opposite directions along the y-axis, so their magnitudes subtract.

3

Calculate the magnitude of the resultant displacement vector using Pythagoras' theorem.

|\vec{R}| = \sqrt{R_x^2 + R_y^2} = \sqrt{12^2 + (-5)^2} = \sqrt{144 + 25} = \sqrt{169} = 13\text{ km}

.

Perpendicular components combine geometrically to give the magnitude of the resultant vector.

Key Concept

Vector resolution and addition of non-collinear displacement vectors.

Estimated Time:1m 30s

Question 13790Question →

Match each international environmental agreement on the left with its primary global environmental mandate on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Minamata Convention pairs with regulation and reduction of anthropogenic mercury emissions; Rotterdam Convention pairs with implementation of Prior Informed Consent for trade in hazardous chemicals; Bonn Convention (CMS) pairs with protection and conservation of migratory species of wild animals; UNCCD pairs with mitigation of land degradation and drought impacts.

Each agreement is correctly aligned with its governing purpose: Minamata protects health and nature from toxic mercury; Rotterdam mandates Prior Informed Consent for trade in hazardous pesticides and chemicals; Bonn protects migratory wild species across political borders; and UNCCD combats desertification and land degradation in dry regions.

Step-by-Step Solution

1

Analyze the primary environmental target or resource focus of each international agreement.

Minamata focuses on toxic mercury pollution, Rotterdam addresses dangerous chemical trade regulation, Bonn targets transboundary wildlife migration, and UNCCD focuses on dryland degradation and drought.

Global environmental governance establishes specialized treaties to handle specific ecological challenges.

2

Pair each listed treaty with its corresponding formal global mandate.

All four conventions on the left align directly with their respective specific environmental objectives on the right.

Matching treaty names to their statutory mandates evaluates comprehension of global conservation initiatives.

Key Concept

International Environmental Treaties and Global Conservation Mandates

Question 13791Question →

Which of the following characteristics best distinguishes organically formed sedimentary rocks from mechanically formed sedimentary rocks?

They originate from the accumulation and compaction of plant or animal remains rather than physical rock fragments.

They are formed when pre-existing rocks are subjected to intense heat and pressure deep within the Earth's crust.

They are created directly by the down-slope movement and accumulation of weathered regolith under gravity.

They result from the rapid cooling and crystallization of molten lava on the Earth's surface.

Show answer & explanation

Answer: They originate from the accumulation and compaction of plant or animal remains rather than physical rock fragments.

Answer

Organically formed sedimentary rocks originate from the accumulation and compaction of plant or animal remains rather than physical rock fragments.

Organically formed sedimentary rocks originate from the remains of once-living organisms, such as vegetation (forming coal and lignite) or sea shells (forming coral limestone). In contrast, mechanically formed sedimentary rocks are composed of inorganic rock debris transported and deposited by agents like water, wind, or ice.

Step-by-Step Solution

1

Classify sedimentary rocks by their mode of origin.

Sedimentary rocks are categorized into mechanically formed (clastic), organically formed, and chemically formed types.

Understanding the genetic origins enables distinct separation of rock formation mechanisms.

2

Compare the constituent materials of organic vs. mechanical sedimentary rocks.

Organically formed rocks (such as coal, peat, and coral limestone) form from organic debris of plant matter or shell remains, whereas mechanically formed rocks (such as sandstone and shale) consist of cemented detrital particles.

The source material (organic debris vs. mineral grains) serves as the primary distinguishing property.

Key Concept

Classification and Formation of Sedimentary Rocks

Question 13792Question →

Match each climatic control listed on the left with its primary physical effect on global climate patterns on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Latitude controls solar incidence angles and thermal zones; Continentality creates extreme annual temperature ranges in landlocked interiors; Cold Ocean Currents produce atmospheric stability and coastal hyper-aridity; Altitude causes temperature drops at the environmental lapse rate.

Latitude directly governs the solar angle of incidence across global thermal zones. Continentality removes sea-buffering, resulting in extreme annual temperature ranges. Cold ocean currents cool lower air layers, creating stable atmospheric conditions and coastal hyper-aridity. Altitude reduces temperature predictably through adiabatic expansion and reduced air density at the standard lapse rate.

Step-by-Step Solution

1

Analyze the primary atmospheric mechanism of each climatic control

Latitude governs solar angle; Continentality removes maritime thermal buffering; Cold currents stabilize coastal air; Altitude reduces air temperature via lapse rates.

Climatic controls act systematically to modify air temperature, atmospheric pressure, and moisture availability globally.

2

Pair each climatic control with its exact physical outcome

Latitude matches solar zone establishment; Continentality matches large annual temperature range; Cold currents match atmospheric inversion/coastal deserts; Altitude matches environmental lapse rate.

Matching structural cause-and-effect relationships explains observed geographical distributions of weather parameters.

Key Concept

Controls of Weather and Climate

Question 13793Question →

Coastal Maritime Ltd approaches Premier Insurance Company to cover a high-value oil tanker. Before issuing the policy, Premier Insurance Company assesses the physical condition of the vessel, examines past loss records, calculates the appropriate premium, and determines the terms under which the risk will be accepted. Which specialized insurance operation is Premier Insurance Company carrying out?

Underwriting

Reinsurance

Co-insurance

Subrogation

Show answer & explanation

Answer: Underwriting

Answer

Underwriting

Underwriting refers specifically to the procedure carried out by an insurer to evaluate potential risks, set premium rates, and define policy conditions before assuming legal liability.

Step-by-Step Solution

1

Identify the key activities described in the scenario

The insurer is examining risk factors, reviewing loss history, determining premiums, and establishing policy terms prior to issuing coverage.

These actions are required to evaluate whether a risk is acceptable and on what monetary terms.

2

Match these activities to standard commercial insurance functions

The process of risk selection, evaluation, pricing, and setting conditions before policy issuance is defined as underwriting.

Underwriting serves as the fundamental risk-assessment and policy-pricing mechanism of an insurance company.

Key Concept

Underwriting process and risk assessment in insurance

Estimated Time:1m 0s

Question 13794Question →

Newton's law of universal gravitation states that the gravitational force $F$ between two point masses $m_1$ and $m_2$ separated by a distance $r$ is given by $F = \frac{G m_1 m_2}{r^2}$ , where $G$ is the universal gravitational constant. What is the dimensional formula of $G$ ?

M L^3 T^{-2}

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

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

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

Show answer & explanation

Answer: $M^{-1} L^3 T^{-2}$

Answer

The dimensional formula of the universal gravitational constant

G

is

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

.

Rearranging

F = \frac{G m_1 m_2}{r^2}

gives

G = \frac{F r^2}{m_1 m_2}

. Substituting the dimensions of Force (

M L T^{-2}

), distance squared (

L^2

), and mass squared (

M^2

) gives

\frac{(M L T^{-2})(L^2)}{M^2} = M^{-1} L^3 T^{-2}

.

Step-by-Step Solution

1

Rearrange the gravitational force equation to solve for

G

.

G = \frac{F r^2}{m_1 m_2}

Isolating the physical constant allows us to substitute the dimensions of each constituent quantity.

2

Substitute the fundamental dimensions for force, distance, and mass.

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

,

[r] = L

,

[m_1] = [m_2] = M

Force is mass times acceleration (

M \cdot L T^{-2}

), distance is length (

L

), and mass is

[M]

.

3

Substitute these fundamental dimensions into the expression for

G

and simplify the exponents.

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

Applying standard exponent rules yields the final dimensional formula.

Key Concept

Deriving Dimensions of Physical Constants

Question 13795Question →

Match each fluvial or subterranean groundwater feature listed in Column A with its corresponding defining formation mechanism or spatial characteristic in Column B.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Interlocking spurs match with alternating projections of resistant rock in a youth-stage V-shaped valley; Polje matches with a large, flat-floored basin in karst terrain formed by sinkhole coalescence; Natural levee matches with a raised embankment of coarse sediment deposited along stream margins during flood conditions; Stalagmite matches with a mound of calcite built up vertically from a cave floor.

Each landform is accurately paired according to its characteristic formative process: interlocking spurs represent upper-course fluvial erosion, polje is a massive surface karst solution basin, natural levee is a lower-course river depositional embankment, and stalagmite is a subterranean karst precipitation feature.

Step-by-Step Solution

1

Categorize each given geomorphic landform by its primary process environment (fluvial erosion, fluvial deposition, surface karst, or subterranean karst).

Interlocking spurs are upper-course fluvial erosional features; poljes are surface karst solution features; natural levees are lower-course fluvial depositional features; stalagmites are subterranean karst depositional features.

Grouping landforms by agent and stage simplifies identification of matching physical descriptions.

2

Match interlocking spurs with the upper-course river channel profile.

Interlocking spurs correspond to the alternating projections of resistant rock in a V-shaped valley.

Vertical headward cutter erosion in the youth stage forces streams around obstacles rather than through them.

3

Match polje with its characteristic karst surface landform scale and origin.

Polje corresponds to a large flat-floored basin produced by sinkhole coalescence and solution.

Poljes represent advanced surface solution features in limestone regions.

4

Match natural levee with its flood plain deposition mechanism.

Natural levee corresponds to raised embankments of coarse sediment along stream banks.

Fluvial flooding causes rapid loss of hydraulic energy at bankfull margins, dropping heavy sediment first.

5

Match stalagmite with its cave dripstone growth orientation.

Stalagmite corresponds to calcite mounds building up vertically from cave floors.

Calcium-rich drips falling from the cave roof lose carbon dioxide upon reaching the floor, depositing calcium carbonate upward.

Key Concept

Classification of landforms produced by surface stream action and underground carbonation-solution processes

Question 13796Question →

Arrange the following sequential stages in the formation and development of a coastal spit via longshore drift, starting from initial wave action to the creation of a recurved tip.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct order of stages in spit development is: 1) Waves driven by prevailing winds carry swash obliquely up the shore face, 2) Gravity pulls backwash straight down perpendicular to the coast, 3) Continuous longshore drift moves sediment past a bend in the coastline into sheltered water, 4) Deposition extends a narrow ridge of sediment outward into open water, and 5) Secondary winds and wave refraction curve the distal end of the ridge inland to form a recurved tip.

The development of a coastal spit begins with prevailing winds pushing wave swash obliquely up the beach face, followed by gravity pulling backwash straight down the slope perpendicular to the shore. This repeated cycle creates longshore drift, which carries sediment laterally along the beach face. When the drift reaches a break in the coastline, such as an estuary mouth or sheltered bay, reduced wave energy causes deposition. A linear sand ridge builds outward into open water, anchored at one end. Eventually, secondary wind forces and wave refraction curve the free distal end inland, producing a recurved spit with a hooked end.

Step-by-Step Solution

1

Identify the primary mechanism initiating lateral sediment movement along the shoreline.

Prevailing winds push waves toward the beach at an angle, propelling swash and sediment diagonally up the shore face.

Swash direction directly reflects the prevailing wind direction relative to the coastline.

2

Determine the path of sediment return during wave recoil.

Gravity pulls water and sediment straight down the slope of the beach perpendicular to the shoreline.

Gravity acts vertically down the steepest beach gradient regardless of wind angle.

3

Trace the movement of sediment as it encounters a change in coast orientation.

Longshore drift moves sediment past the corner of a headland or river estuary into calmer, deeper water.

Deposition begins when wave energy decreases in sheltered inlet waters.

4

Follow the structural growth of the deposited sediment body.

Continuous accumulation extends a narrow linear ridge of sand or shingle into the water, anchored to the mainland at one end.

Sediment builds up along the original line of drift past the mainland break.

5

Analyze how the final curved morphology of the landform develops.

Changes in prevailing wind direction and wave refraction around the open end push sediment inland, forming a hook.

Refracted waves alter the orientation of deposition at the unattached distal end.

Key Concept

Coastal spit evolution through longshore drift and wave refraction

Question 13797Question →

At a coastal meteorological station in Calabar, air temperature observations recorded at four specific intervals during a 24-hour cycle were $22.0^\circ\text{C}$ , $31.5^\circ\text{C}$ , $28.5^\circ\text{C}$ , and $24.0^\circ\text{C}$ . What is the mean temperature of these observations in $^\circ\text{C}$ ?

Show answer & explanation

Answer: 26.5

Answer

The mean temperature computed from the four observations is

26.5^\circ\text{C}

.

The mean temperature is calculated by summing all recorded values (

22.0 + 31.5 + 28.5 + 24.0 = 106.0^\circ\text{C}

) and dividing by the total number of observations (

4

), resulting in

26.5^\circ\text{C}

.

Step-by-Step Solution

1

Sum all four temperature values taken across the observation periods.

The total sum is

22.0^\circ\text{C} + 31.5^\circ\text{C} + 28.5^\circ\text{C} + 24.0^\circ\text{C} = 106.0^\circ\text{C}

.

Finding the arithmetic mean requires calculating the aggregate total of all recorded temperature data points.

2

Divide the calculated aggregate sum by the count of observation intervals.

\frac{106.0^\circ\text{C}}{4} = 26.5^\circ\text{C}

.

Dividing the sum by the sample size (

4

) yields the average temperature across the recorded intervals.

Key Concept

Calculation of mean temperature from periodic daily observations

Estimated Time:1m 30s

Question 13798Question →

A galvanometer has an internal resistance of $50\ \Omega$ and gives a full-scale deflection for a current of $2.0\text{ mA}$ . What multiplier resistance must be connected in series with the galvanometer to convert it into a voltmeter capable of measuring potential differences up to $10.0\text{ V}$ ?

4950\ \Omega

5000\ \Omega

5050\ \Omega

450\ \Omega

Show answer & explanation

Answer: $4950\ \Omega$

Answer

The required multiplier resistance is

4950\ \Omega

.

To convert a galvanometer to a voltmeter, a high-resistance multiplier

R_m

is connected in series. The maximum voltage

V

measured by the voltmeter is given by

V = I_g(G + R_m)

. Substituting

V = 10.0\text{ V}

,

I_g = 0.002\text{ A}

, and

G = 50\ \Omega

, we find

R_m = \frac{10.0}{0.002} - 50 = 4950\ \Omega

.

Step-by-Step Solution

1

Convert given values to standard SI units.

Galvanometer resistance

G = 50\ \Omega

, full-scale current

I_g = 2.0\text{ mA} = 0.002\text{ A}

, maximum voltage

V = 10.0\text{ V}

.

Electric current must be expressed in amperes (A) for standard circuit calculations.

2

Apply the series multiplier formula for a voltmeter.

V = I_g(G + R_m) \implies 10.0 = 0.002 \times (50 + R_m)

.

Converting a galvanometer to a voltmeter requires connecting a high resistance

R_m

in series so that the total voltage drop equals

V

.

3

Solve for the multiplier resistance

R_m

.

50 + R_m = \frac{10.0}{0.002} = 5000 \implies R_m = 5000 - 50 = 4950\ \Omega

.

Subtracting the internal resistance

G

from total resistance gives the value of the multiplier resistor alone.

Key Concept

Galvanometer Conversion to Voltmeter

Estimated Time:1m 30s

Question 13799Question →

Following the revocation of a distressed commercial bank's operating license in Nigeria, individual depositors are compensated up to a statutory limit to prevent loss of their savings. Which financial regulatory body is legally mandated to provide this deposit insurance coverage?

Securities and Exchange Commission

Nigeria Deposit Insurance Corporation

Federal Competition and Consumer Protection Commission

Nigerian Investment Promotion Commission

Show answer & explanation

Answer: Nigeria Deposit Insurance Corporation

Answer

The Nigeria Deposit Insurance Corporation (NDIC) is the regulatory agency legally mandated to insure bank deposits and compensate depositors upon bank failure.

The Nigeria Deposit Insurance Corporation (NDIC) is statutorily empowered to insure deposit liabilities of licensed banking institutions in Nigeria, guaranteeing compensation to depositors up to specified statutory limits if a bank fails.

Step-by-Step Solution

1

Identify the primary financial protection function described in the scenario.

The core function is protecting bank depositors against loss by guaranteeing reimbursement up to a legal threshold upon bank failure.

The stem specifies compensating commercial bank account holders following license revocation.

2

Distinguish between the statutory mandates of major Nigerian financial regulatory bodies.

The Nigeria Deposit Insurance Corporation (NDIC) directly insures deposit liabilities, whereas the Securities and Exchange Commission (SEC) oversees capital market securities.

NDIC works alongside the Central Bank of Nigeria to protect banking sector depositors and promote stability.

Key Concept

Functions and Mandate of the Nigeria Deposit Insurance Corporation (NDIC)

Question 13800Question →

In arid regions, mushroom rocks (pedestal rocks) typically exhibit a narrow, undercut base beneath a broader cap rock. Which geomorphic factor explains why wind abrasion is most severe within the lowest one meter of the rock structure?

Abrasive sand grains transported by saltation are too heavy to be lifted high and bounce mainly near ground level.

Deflation selectively removes fine silt from the base while ice plucking breaks down the upper rock structure.

Flash flood waters in arid valleys carve out the lower section of the rock before wind deposition covers the top.

Frictional resistance causes wind speed to be highest at ground level, maximizing kinetic impact at the base.

Show answer & explanation

Answer: Abrasive sand grains transported by saltation are too heavy to be lifted high and bounce mainly near ground level.

Answer

The maximum rate of wind abrasion occurs near the base of rock outcrops because sand grains moved by wind travel mainly by saltation within the lowest meter above the surface.

Wind abrasion requires abrasive tools, specifically sand grains. In desert environments, wind transports coarse sand primarily via saltation—a process where grains bounce along the ground, rarely rising above 1 meter. Consequently, the greatest density of abrasive impacts occurs near the base of an outcrop, wearing it away faster than the upper portion and producing the characteristic mushroom or pedestal shape.

Step-by-Step Solution

1

Identify the primary process responsible for shaping mushroom rocks in arid environments.

Mushroom rocks (gours) are shaped primarily by aeolian abrasion (sandblasting of solid rock by wind-borne grains).

Understanding the agent and process sets the framework for analyzing the vertical distribution of erosion.

2

Analyze the mode of transport and elevation range of abrasive particles.

Wind carries fine dust in suspension high into the air, but heavy sand grains move by saltation (bouncing) and stay below 1 to 2 meters.

The concentration of hard, sharp sand tools is highest near the surface.

3

Determine why undercutting occurs specifically near the base.

Because abrasive sand is concentrated in the lowest meter, maximum rock removal happens near the ground, producing a narrow pedestal.

This explains the differential erosion rate between the base and the upper rock cap.

Key Concept

Wind Abrasion and Saltation Mechanics

Answer

Step-by-Step Solution

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