Physical Geography Practice Questions — JAMB UTME — Page 6

Question 101Question →

A solar eclipse reaches maximum totality in Town P, located at longitude $15^\circ\text{W}$ , at $11:20\text{ AM}$ local time. What is the local time in Town Q, located at longitude $45^\circ\text{E}$ , at that exact moment?

3:20\text{ PM}

7:20\text{ AM}

1:20\text{ PM}

9:20\text{ AM}

Show answer & explanation

Answer: $3:20\text{ PM}$

Answer

The local time in Town Q is

3:20\text{ PM}

.

Because Town P (

15^\circ\text{W}

) and Town Q (

45^\circ\text{E}

) are in opposite hemispheres, the total longitudinal distance between them is

15^\circ + 45^\circ = 60^\circ

. Since

15^\circ

equals

1

hour of time difference,

60^\circ

equals

4

hours. Because Town Q is situated east of Town P, time is ahead in Town Q. Adding

4

hours to

11:20\text{ AM}

yields

3:20\text{ PM}

.

Step-by-Step Solution

1

Calculate the total longitudinal difference between Town P (

15^\circ\text{W}

) and Town Q (

45^\circ\text{E}

).

Longitudinal difference

= 15^\circ + 45^\circ = 60^\circ

.

Since the towns are in opposite hemispheres (West and East), their longitudes are added to find the total angular distance.

2

Convert the longitudinal difference into time.

Time difference

= 60^\circ \div 15^\circ/\text{hour} = 4\text{ hours}

.

The Earth rotates

15^\circ

per hour (

1^\circ

every

4

minutes).

3

Determine the time in Town Q relative to Town P.

Local time in Town Q

= 11:20\text{ AM} + 4\text{ hours} = 3:20\text{ PM}

.

Town Q lies to the east of Town P, so its time is ahead of Town P's local time.

Key Concept

Longitude and Time Calculations Across Meridians

Estimated Time:1m 30s

Question 102Question →

Town P is located at longitude $60^\circ\text{E}$ , where the local solar time is $12:00\text{ noon}$ . Town Q is located at longitude $15^\circ\text{W}$ . What is the local solar time at Town Q, expressed as the hour of the day in 24-hour time?

Show answer & explanation

Answer: 7

Answer

The local solar time at Town Q is 7:00 (represented by the number 7).

To find the local time at Town Q (

15^\circ\text{W}

) relative to Town P (

60^\circ\text{E}

at

12:00\text{ noon}

), calculate the longitudinal distance:

60^\circ + 15^\circ = 75^\circ

. Dividing by

15^\circ

per hour gives a time difference of

5\text{ hours}

. Because Town Q is west of Town P, subtract 5 hours from 12:00 to obtain 7:00 (

7

).

Step-by-Step Solution

1

Calculate the longitudinal difference between Town P and Town Q.

Total angular separation =

60^\circ\text{E} + 15^\circ\text{W} = 75^\circ

.

Locations in opposite hemispheres (East and West) require adding their longitude values to determine total angular distance.

2

Convert the angular distance into hours.

Time difference =

75^\circ \div 15^\circ/\text{hour} = 5\text{ hours}

.

Earth rotates

360^\circ

in 24 hours, which corresponds to

15^\circ

per hour.

3

Adjust time based on relative position.

Local time at Town Q =

12:00 - 5\text{ hours} = 7:00

(

7

).

Town Q lies to the west of Town P, so its local time is behind that of Town P.

Key Concept

Calculating local solar time across different longitudes in opposite hemispheres.

Question 103Question →

The Earth's outer crust is divided into continental and oceanic layers based on density and mineral composition. Which of the following statements correctly describes the sial layer of the Earth's crust?

It forms a continuous layer under the ocean floors composed mainly of basaltic rocks created through marine sediment deposition.

It forms the lighter upper continental crust composed predominantly of silica and aluminium, floating above the denser sima layer.

It consists of loose surface debris moved down slopes under the direct force of gravity across continental margins.

It represents the dense metallic core of the Earth dominated by molten iron and nickel below the mantle.

Show answer & explanation

Answer: It forms the lighter upper continental crust composed predominantly of silica and aluminium, floating above the denser sima layer.

Answer

The sial layer forms the lighter upper continental crust composed predominantly of silica and aluminium, floating above the denser sima layer.

The sial layer forms the discontinuous outer layer of the Earth's crust found mainly on continents. It is composed chiefly of granitic rocks rich in silica and aluminium, with a lower density that allows it to float upon the continuous, denser sima layer underneath.

Step-by-Step Solution

1

Identify the chemical composition and position of the sial layer.

Sial derives its name from Silica (Si) and Aluminium (Al) and makes up the upper continental crust.

Geophysical composition divides the outer crust into upper sial and lower sima.

2

Compare the density of sial relative to sima.

Sial has an average density of about 2.7 g/cm³, making it lighter than the underlying sima (density ~3.0 g/cm³).

Due to its lower density, continental sial floats upon the denser basaltic sima layer.

Key Concept

Chemical zonation of the Earth's crust (Sial vs. Sima)

Estimated Time:1m 0s

Question 104Question →

A research station located at longitude $142^\circ\text{E}$ records a solar flare observation at $03:16\text{ PM}$ local solar time. At the exact same instant, an oceanographic vessel records the same solar flare at $07:48\text{ AM}$ local solar time on the same day. What is the longitude of the oceanographic vessel in degrees East?

Show answer & explanation

Answer: 30

Answer

The longitude of the oceanographic vessel is

30^\circ\text{E}

.

The research station's local solar time is 15:16 and the oceanographic vessel's time is 07:48, giving a difference of 7 hours 28 minutes (448 minutes). Since

1^\circ

of longitude corresponds to 4 minutes of time, the longitudinal difference is

448 \div 4 = 112^\circ

. Because the vessel's local solar time is earlier than that of the research station, the vessel is located to the west of the research station (

142^\circ\text{E} - 112^\circ = 30^\circ\text{E}

).

Step-by-Step Solution

1

Convert both local solar times to 24-hour time format and subtract to determine the exact time difference

Research station time = 15:16, Vessel time = 07:48. Time difference = 7 hours 28 minutes (448 minutes).

Converting to 24-hour format simplifies direct subtraction to evaluate the total time delta between the two locations.

2

Convert the total time difference in minutes to angular longitudinal distance

448 minutes ÷ 4 minutes per degree = 112° difference in longitude.

Earth rotates 360° in 24 hours (1440 minutes), establishing a rate of 1° longitude change per 4 minutes of local time difference.

3

Evaluate direction of location and subtract angular distance from the station's longitude

Vessel time is behind station time, placing it west of the station: 142°E - 112° = 30°E.

Places located further west experience earlier local solar time. Subtracting 112° from 142°E yields 30°E.

Key Concept

Longitude and Time Calculations (converting solar time difference to longitudinal angular distance)

Question 105Question →

An aircraft departs from City A located at longitude $35^\circ\text{W}$ at $08:45\text{ AM}$ local time on Tuesday for a non-stop flight to City B located at longitude $105^\circ\text{E}$ . If the total flight duration is 14 hours and 30 minutes, what is the local time and day of arrival at City B?

08:35\text{ AM}

on Wednesday

01:55\text{ PM}

on Tuesday

03:55\text{ AM}

on Wednesday

08:35\text{ PM}

on Tuesday

Show answer & explanation

Answer: $08:35\text{ AM}$ on Wednesday

Answer

08:35\text{ AM}

on Wednesday

The longitudinal difference between

35^\circ\text{W}

and

105^\circ\text{E}

is

140^\circ

, equivalent to a 9-hour 20-minute time difference. Since City B is east of City A, its time is ahead by 9 hours and 20 minutes, giving a local departure time at City B of

06:05\text{ PM}

Tuesday. Adding the 14-hour 30-minute flight duration brings the time to

08:35\text{ AM}

on Wednesday.

Step-by-Step Solution

1

Calculate the total longitudinal difference between City A (

35^\circ\text{W}

) and City B (

105^\circ\text{E}

).

\text{Longitude difference} = 35^\circ + 105^\circ = 140^\circ

Because the two places are in opposite hemispheres (West and East), their longitudinal values must be added.

2

Convert the longitudinal difference into a time difference.

140^\circ \times 4\text{ minutes/degree} = 560\text{ minutes} = 9\text{ hours and } 20\text{ minutes}

Earth rotates

1^\circ

every 4 minutes.

3

Determine the local time at City B when the flight departs from City A.

08:45\text{ AM} + 9\text{ hours } 20\text{ minutes} = 06:05\text{ PM}\text{ (or } 18:05\text{)} \text{ on Tuesday}

Places to the East are ahead in time, so the time difference must be added to City A's departure time.

4

Add the flight duration to City B's departure time to find arrival time and day.

18:05 + 14\text{ hours } 30\text{ minutes} = 32:35 \Rightarrow 08:35\text{ AM} \text{ on Wednesday}

32:35

represents 8 hours and 35 minutes past midnight, which advances the calendar date by one day from Tuesday to Wednesday.

Key Concept

Calculation of time differences across eastern and western hemispheres considering flight duration and day change

Question 106Question →

A town is located at longitude $45^\circ\text{E}$ . If the Greenwich Mean Time (GMT) is 8:00 a.m., what is the local time in the town?

5:00 a.m.

11:00 a.m.

11:00 p.m.

2:00 p.m.

Show answer & explanation

Answer: 11:00 a.m.

Answer

The local time in the town is 11:00 a.m.

Earth rotates from west to east, meaning places to the east experience solar noon earlier than places to the west. For every

15^\circ

of longitude moving eastward, time increases by 1 hour. Since the town is at

45^\circ\text{E}

, it is

45^\circ / 15^\circ = 3

hours ahead of Greenwich Mean Time (8:00 a.m.), making the local time 11:00 a.m.

Step-by-Step Solution

1

Calculate the longitudinal difference between Greenwich Meridian (

0^\circ

) and the town (

45^\circ\text{E}

).

Longitudinal difference =

45^\circ - 0^\circ = 45^\circ

.

The longitudinal difference determines the total angular distance between the two locations.

2

Convert the longitudinal difference into time using the rate of

15^\circ = 1\text{ hour}

(or

1^\circ = 4\text{ minutes}

).

Time difference =

45^\circ \times 4\text{ minutes} = 180\text{ minutes} = 3\text{ hours}

.

Earth rotates

360^\circ

in 24 hours, which corresponds to

15^\circ

per hour.

3

Apply the rule 'East gain, West lose' relative to Greenwich Mean Time.

8:00 a.m. + 3 hours = 11:00 a.m.

Since the destination is east of the Greenwich Meridian, local time is ahead of GMT.

Key Concept

Longitude and Local Time Calculation

Question 107Question →

Geophysical observations indicate that shear ( $S$ ) seismic waves cannot travel through the outer core, while the partially molten asthenosphere enables mechanical movement of the rigid outer shell above it. Which of the following statements accurately explains the physical properties and dynamic interaction of these internal and external structural layers of the Earth?

The asthenosphere exhibits ductile plastic flow that supports lithospheric plate motion, while the liquid state of the outer core absorbs shear stress and blocks

S

-wave transmission.

The sial layer continuously converts into metamorphic marble beneath the oceans to produce mantle convection currents within the solid inner core.

The barysphere undergoes in-situ chemical weathering to generate downslope mass wasting movements that form the Earth's atmosphere.

The oceanic crust consists of light granitic rocks that undergo sedimentary deposition inside the mesosphere to stop

P

-wave transmission.

Show answer & explanation

Answer: The asthenosphere exhibits ductile plastic flow that supports lithospheric plate motion, while the liquid state of the outer core absorbs shear stress and blocks $S$ -wave transmission.

Answer

The asthenosphere exhibits ductile plastic flow that supports lithospheric plate motion, while the liquid state of the outer core absorbs shear stress and blocks

S

-wave transmission.

The asthenosphere's partially molten, ductile nature allows it to deform plastically, providing the lubricated substrate over which rigid lithospheric plates move. Furthermore, shear (

S

) waves cannot propagate through liquid media because liquids lack shear strength, which accounts for the

S

-wave shadow zone produced by the liquid metallic outer core.

Step-by-Step Solution

1

Analyze the physical state and function of the asthenosphere and lithosphere.

The asthenosphere, situated in the upper mantle, exists in a semi-fluid or ductile state. This plasticity allows the cooler, rigid lithospheric plates floating above it to undergo movement.

Internal heat differential drives plastic flow in the asthenosphere, enabling plate tectonics.

2

Evaluate seismic wave behavior through liquid internal layers.

Transverse (

S

) waves require shear strength to propagate through a medium. Because liquids have zero shear strength,

S

-waves are completely blocked by the liquid outer core.

The boundary between the solid mantle and liquid outer core (Gutenberg Discontinuity) causes an

S

-wave shadow zone.

Key Concept

Physical state, seismic wave propagation, and dynamic interaction of Earth's internal layers (asthenosphere, outer core) and external lithosphere.

Estimated Time:1m 30s

Question 108Question →

Town A is situated at longitude $20^\circ\text{W}$ . When the local solar time at Town A is $09:00\text{ AM}$ , the local solar time at Town B is $01:00\text{ PM}$ on the same day. What is the longitude of Town B in degrees East?

Show answer & explanation

Answer: 40

Answer

The longitude of Town B is 40°E.

Town B is 4 hours ahead of Town A, which corresponds to an angular distance of

60^\circ

East (

4 \times 15^\circ

). Traveling

60^\circ

East starting from

20^\circ\text{W}

takes

20^\circ

to reach the Prime Meridian (

0^\circ

), and the remaining

40^\circ

places Town B at

40^\circ\text{E}

.

Step-by-Step Solution

1

Calculate the difference in local solar time between Town A and Town B.

Time difference =

13:00 - 09:00 = 4\text{ hours}

.

Local solar time differences represent angular distance between meridians.

2

Convert the time difference into degrees of longitude.

4\text{ hours} \times 15^\circ/\text{hour} = 60^\circ

longitude difference.

The Earth rotates

360^\circ

in 24 hours, which corresponds to

15^\circ

of longitude per hour.

3

Determine direction and calculate the exact longitude of Town B.

Moving

60^\circ

East from

20^\circ\text{W}

gives

40^\circ\text{E}

.

Because Town B has a later time, it lies to the East. Subtracting

20^\circ

reaches the Prime Meridian (

0^\circ

), leaving

40^\circ

in the Eastern Hemisphere.

Key Concept

Calculating Longitude from Local Solar Time Differences Across Meridians

Estimated Time:1m 30s

Question 109Question →

Arrange the following inner (terrestrial) planets of the solar system in order of INCREASING distance from the Sun (starting with the planet closest to the Sun).

Drag items to arrange them in the correct order

Show answer & explanation

Answer

Mercury → Venus → Earth → Mars

In order of increasing distance from the Sun, the terrestrial planets are Mercury (1st), Venus (2nd), Earth (3rd), and Mars (4th).

Step-by-Step Solution

1

Identify the terrestrial (inner) planets in the solar system

The four inner terrestrial planets are Mercury, Venus, Earth, and Mars.

These four planets lie within the asteroid belt and are composed primarily of rock and metal.

2

Recall their average distances from the Sun

Mercury lies at

0.39\text{ AU}

, Venus at

0.72\text{ AU}

, Earth at

1.00\text{ AU}

, and Mars at

1.52\text{ AU}

.

Distance from the Sun increases systematically outward along their orbits.

3

Arrange the planets from closest to farthest

The correct sequence is Mercury → Venus → Earth → Mars.

This places the planets in ascending order of their orbital radius from the Sun.

Key Concept

Planetary Sequence and Relative Distance from the Sun

Question 110Question →

A scientific research vessel positioned at longitude $48.5^\circ\text{W}$ records its local solar time as 3:34 p.m. At that exact instant, a terrestrial tracking station records its local solar time as 9:10 a.m. on the same day. What is the longitude of the tracking station in degrees West?

Show answer & explanation

Answer: 144.5

Answer

The longitude of the tracking station is

144.5^\circ\text{W}

.

The difference in local solar time between 3:34 p.m. (15:34) and 9:10 a.m. (09:10) is 6 hours and 24 minutes, or 384 minutes. Dividing 384 minutes by 4 minutes per degree gives a longitude difference of

96^\circ

. Since the tracking station is behind in time relative to the vessel, it must be located west of

48.5^\circ\text{W}

. Adding

96^\circ

westward yields a final longitude of

144.5^\circ\text{W}

.

Step-by-Step Solution

1

Calculate the total time difference between the vessel and the tracking station.

Time difference = 15:34 - 09:10 = 6 hours and 24 minutes = 384 minutes.

Determining the net difference in local time is required to find the angular displacement.

2

Convert time difference in minutes to degrees of longitude.

Longitudinal distance = 384 minutes / 4 minutes per degree = 96 degrees.

Earth rotates

360^\circ

in 24 hours, which corresponds to

1^\circ

of longitude every 4 minutes.

3

Apply the longitudinal directional rule ('West lose, East gain') to find the station's location.

Station longitude = 48.5 degrees W + 96 degrees = 144.5 degrees W.

Since the tracking station's local time is behind the vessel's local time, the station must be positioned further west of the vessel.

Key Concept

Longitude calculation from local solar time differences and Earth's axial rotation rate

Question 111Question →

Match each structural layer or boundary of the Earth listed in Column A with its defining physical characteristic or compositional property in Column B.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Mohorovičić Discontinuity matches the boundary separating the crust from the mantle; Gutenberg Discontinuity matches the boundary between the mantle and outer core; Lithosphere matches the rigid outermost shell of crust and upper mantle; Asthenosphere matches the ductile semi-fluid upper mantle zone.

Each structural zone corresponds accurately to its physical state and boundary depth: the Mohorovičić discontinuity separates the crust from the mantle, the Gutenberg discontinuity separates the mantle from the outer core, the lithosphere represents the rigid outermost shell, and the asthenosphere represents the ductile upper mantle region.

Step-by-Step Solution

1

Identify seismic boundaries

Mohorovičić discontinuity separates crust from mantle, while Gutenberg discontinuity separates lower mantle from outer core.

Seismic velocity changes sharply at structural compositional transitions.

2

Distinguish physical state layers

Lithosphere is brittle/rigid outermost zone; Asthenosphere is ductile/semi-fluid underlying zone.

Mechanical properties differ based on temperature and pressure regimes.

Key Concept

Earth's Internal Discontinuities and Mechanical Spheres

Question 112Question →

Match each Earth layer or structural boundary listed in Column A with its defining physical or compositional characteristic in Column B.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Conrad Discontinuity matches the boundary between sial and sima crustal layers; Asthenosphere matches the ductile upper mantle zone; Stratosphere matches the atmospheric ozone heating zone; Barysphere matches the dense iron-nickel core.

Each feature correctly pairs its structural location with its chemical or physical attribute: the Conrad Discontinuity divides sialic and simatic crust, the Asthenosphere acts as the ductile upper mantle layer, the Stratosphere contains the protective ozone layer, and the Barysphere forms the dense central core region.

Step-by-Step Solution

1

Identify the internal boundary separating the upper continental crust from the lower crustal layer.

The Conrad discontinuity separates the granitic sial layer from the denser basaltic sima layer.

Geophysical observations show a distinct seismic velocity transition between continental sial and oceanic sima.

2

Analyze upper mantle rheology and thermal structure.

The asthenosphere is the weak, plastic layer of the upper mantle directly underlying the rigid lithosphere.

Partial melting allows convection currents to drag tectonic plates across the asthenosphere.

3

Examine thermal profile and chemical features of Earth's atmospheric envelope.

The stratosphere houses the ozone layer where ultraviolet radiation absorption leads to vertical temperature increases.

Solar UV absorption by O3 molecules converts radiant energy into heat within the atmospheric stratosphere.

4

Determine the compositional term for Earth's innermost structural core.

The barysphere represents the high-density interior metallic core consisting predominantly of nickel and iron (nife).

Gravitational and seismic data confirm the high-density metallic core situated at Earth's center.

Key Concept

Internal and External Structure of the Earth

Estimated Time:1m 30s

Question 113Question →

A radio signal transmitted live from Station X, located at longitude $78^\circ\text{E}$ , is logged at $10:40\text{ AM}$ local solar time. At the exact same instant, the signal is received at Station Y, where the local solar time is logged as $03:16\text{ PM}$ on the same day. What is the longitude of Station Y in degrees East?

Show answer & explanation

Answer: 147

Answer

147°E

The time difference between 10:40 AM and 03:16 PM is 4 hours and 36 minutes. Converting this time difference to degrees using

15^\circ

per hour (

4 \times 15^\circ = 60^\circ

) and

1^\circ

per 4 minutes (

36 \text{ min} / 4 \text{ min/degree} = 9^\circ

) gives a total longitudinal distance of

69^\circ

. Because Station Y has a later solar time than Station X, it is situated further East. Adding

69^\circ

to

78^\circ\text{E}

yields

147^\circ\text{E}

.

Step-by-Step Solution

1

Calculate the time difference between Station Y and Station X

4 hours and 36 minutes

Subtracting the earlier local time at Station X (10:40 AM) from the later local time at Station Y (03:16 PM) yields a duration of 4 hours and 36 minutes.

2

Convert the calculated time difference into longitudinal degrees

69 degrees

Earth rotates through 15° of longitude per hour (or 1° every 4 minutes). Thus, 4 hours corresponds to 60° and 36 minutes corresponds to 9°, giving a total of 69°.

3

Calculate the longitude of Station Y based on directional time relationship

147°E

Because local time at Station Y is later than at Station X, Station Y lies further East. Adding the angular separation of 69° to 78°E results in 147°E.

Key Concept

Longitude calculation from local time difference

Question 114Question →

The Earth completes a full rotation of $360^\circ$ on its axis every 24 hours. How many degrees of longitude does the Earth rotate through in 3 hours?

Show answer & explanation

Answer: 45

Answer

45 degrees

Because the Earth completes one full

360^\circ

rotation in 24 hours, its speed of rotation is

15^\circ

per hour (

360^\circ \div 24

). In a time span of 3 hours, it turns through

15^\circ \times 3 = 45^\circ

of longitude.

Step-by-Step Solution

1

Calculate the rotation rate of the Earth per hour.

15 degrees per hour

The Earth turns 360 degrees in 24 hours, so 360 divided by 24 equals 15 degrees per hour.

2

Calculate the total longitudinal rotation in 3 hours.

45 degrees

Multiplying the rate of 15 degrees per hour by 3 hours gives 45 degrees.

Key Concept

Earth's Rotational Angular Speed and Longitude

Estimated Time:45s

Question 115Question →

Match each rock in Column I with its corresponding mode of formation or classification in Column II.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Basalt matches fine-grained extrusive igneous rock formed by rapid cooling of surface lava; Marble matches non-foliated metamorphic rock produced by thermal metamorphism of limestone; Coal matches organically formed sedimentary rock derived from compacted vegetative matter; Slate matches foliated metamorphic rock resulting from low-grade regional metamorphism of shale.

Each rock is paired strictly with its genesis: Basalt is formed by rapid lava cooling at the surface (extrusive igneous), Marble is created by thermal metamorphism of limestone, Coal originates from compressed organic plant material (sedimentary), and Slate originates from low-grade regional metamorphism of shale.

Step-by-Step Solution

1

Analyze the formation process of Basalt.

Basalt crystallizes quickly from molten lava on the Earth's exterior.

Extrusive volcanic activity produces fine-grained igneous rock structures.

2

Analyze the transformation of Marble.

Marble forms from limestone exposed to geothermal heat.

Thermal metamorphism converts sedimentary limestone into crystalline calcite rock.

3

Analyze the origin of Coal.

Coal accumulates from decayed organic plant deposits in swampy conditions.

Accumulation and compaction of plant material form organic sedimentary rocks.

4

Analyze the origin of Slate.

Slate develops from shale under mild metamorphic pressure.

Low-grade regional metamorphism realigns clay particles within shale to form slate.

Key Concept

Classification of rocks based on their origin, parent material, and formation processes.

Question 116Question →

Two weather observation stations, Station A and Station B, record simultaneous solar observations. Station A is located at longitude $12^\circ\text{W}$ where the local solar time is $02:00\text{ PM}$ . At the exact same moment, the local solar time at Station B is $07:00\text{ PM}$ . What is the longitude of Station B in degrees East ( $^\circ\text{E}$ )?

Show answer & explanation

Answer: 63

Answer

The longitude of Station B is

63^\circ\text{E}

.

The local time difference between Station A (

02:00\text{ PM}

) and Station B (

07:00\text{ PM}

) is

5\text{ hours}

. Since

1\text{ hour}

equals

15^\circ

of longitude, a

5\text{-hour}

difference equals

75^\circ

of angular distance (

5 \times 15^\circ

). Station B's local time is ahead of Station A, indicating that Station B is located further East. Starting from

12^\circ\text{W}

and moving

75^\circ

East,

12^\circ

is required to reach

0^\circ

(the Prime Meridian), leaving

63^\circ

into the Eastern Hemisphere. Therefore, Station B is located at

63^\circ\text{E}

.

Step-by-Step Solution

1

Calculate the time difference between Station A and Station B.

Station B (

19:00

) is

5\text{ hours}

ahead of Station A (

14:00

).

Comparing local solar times gives the time separation between the two longitudes.

2

Convert the time difference into angular distance in degrees.

5\text{ hours} \times 15^\circ/\text{hour} = 75^\circ

angular distance.

The Earth rotates

360^\circ

in 24 hours, which corresponds to

15^\circ

of longitude per hour.

3

Determine the longitude of Station B from Station A across the Prime Meridian.

75^\circ\text{ East} - 12^\circ\text{W} = 63^\circ\text{E}

.

Station B is later in solar time, so it lies East of Station A. Moving East from

12^\circ\text{W}

uses

12^\circ

to reach

0^\circ

(Prime Meridian) and the remaining

63^\circ

enters the Eastern Hemisphere.

Key Concept

Calculating longitude from local time difference across meridians

Estimated Time:1m 30s

Question 117Question →

Two meteorological stations are situated along different meridians. Station Alpha is positioned at longitude $38^\circ\text{W}$ , while Station Beta is positioned at longitude $82^\circ\text{E}$ . What is the difference in local solar time between these two stations, in hours?

Show answer & explanation

Answer: 8

Answer

The difference in local solar time between the two stations is 8 hours.

Station Alpha is located in the Western Hemisphere (

38^\circ\text{W}

) and Station Beta is located in the Eastern Hemisphere (

82^\circ\text{E}

). The total angular distance separating them across the Greenwich Meridian is

38^\circ + 82^\circ = 120^\circ

. Dividing

120^\circ

by the Earth's rotation speed of

15^\circ

per hour gives a time difference of 8 hours.

Step-by-Step Solution

1

Calculate the total longitudinal angular distance between

38^\circ\text{W}

and

82^\circ\text{E}

.

Angular distance =

38^\circ + 82^\circ = 120^\circ

.

Because the two locations lie in opposite hemispheres relative to the Prime Meridian (

0^\circ

), their longitudinal degree values must be added together.

2

Convert the total angular distance to time difference in hours.

Time difference =

120^\circ \div 15^\circ\text{/hour} = 8\text{ hours}

.

The Earth completes a

360^\circ

rotation in 24 hours, which corresponds to

15^\circ

per hour.

Key Concept

Calculation of longitudinal difference across the Prime Meridian and conversion to local solar time difference.

Question 118Question →

During a field study examining Earth's external structure and surface processes, students observed solid bedrock disintegrating in situ into loose debris without immediate displacement. Which sphere of the Earth is primarily affected by this process, and how is this process correctly distinguished from mass wasting?

Lithosphere; the process is weathering which occurs in situ, while mass wasting involves the gravity-driven downslope movement of rock material.

Lithosphere; the process is weathering which involves downslope movement of debris, while mass wasting refers strictly to in situ disintegration of rock.

Hydrosphere; the process is metamorphism caused by pressure, while mass wasting is the consolidation of marine sediments into sedimentary layers.

Atmosphere; the process is sedimentary deposition, while mass wasting is the thermal recrystallization of metamorphic rock layers.

Show answer & explanation

Answer: Lithosphere; the process is weathering which occurs in situ, while mass wasting involves the gravity-driven downslope movement of rock material.

Answer

Lithosphere; the process is weathering which occurs in situ, while mass wasting involves the gravity-driven downslope movement of rock material.

The correct response identifies the lithosphere as the solid outer sphere where bedrock breaks down. It accurately states that weathering is an in situ process (disintegration on site without transportation), whereas mass wasting involves the movement of weathered material downslope under the direct influence of gravity.

Step-by-Step Solution

1

Identify the Earth sphere containing solid bedrock and surface landforms.

The solid outer shell of the Earth is the lithosphere.

The lithosphere comprises the Earth's crust and uppermost solid mantle where surface geological processes occur.

2

Analyze the observed physical process of in situ rock breakdown.

In situ disintegration without transportation is defined as weathering.

Weathering breaks down rock at its original position through physical, chemical, or biological agents.

3

Differentiate weathering from mass wasting.

Mass wasting specifically requires downslope displacement driven by gravity, whereas weathering does not involve material movement.

A clear distinction between static breakdown (weathering) and gravity-driven transport (mass wasting) is fundamental in physical geography.

Key Concept

Distinction between weathering and mass wasting within Earth's lithosphere

Question 119Question →

A borehole core retrieved during mineral exploration in a complex geological terrain reveals a dense, non-foliated rock composed predominantly of coarse, recrystallized calcite crystals exhibiting an interlocking mosaic texture. If this formation originated from the thermal contact metamorphism of a carbonate sedimentary parent rock adjacent to an igneous intrusion, which of the following correctly identifies the resulting metamorphic rock and its major industrial utility?

Marble, utilized extensively as dimensional building stone and as a raw material in cement manufacture

Quartzite, utilized primarily as a refractory material for furnace linings and glass manufacture

Slate, utilized mainly for roofing tiles, electrical switchboards, and billiard table beds

Limestone, quarried for in-situ soil formation through chemical breakdown and mass wasting

Show answer & explanation

Answer: Marble, utilized extensively as dimensional building stone and as a raw material in cement manufacture

Answer

Marble, utilized extensively as dimensional building stone and as a raw material in cement manufacture

The correct option identifies marble as the product of thermal (contact) metamorphism acting upon carbonate sedimentary rocks such as limestone. Thermal contact metamorphism subjects the surrounding rock to intense heat from magma without directional pressure, turning fine-grained calcite into a dense, non-foliated matrix of recrystallized calcite. Economically, marble is widely quarried for high-grade architectural dimension stone, decorative monuments, and as crushed lime for cement production.

Step-by-Step Solution

1

Analyze the mineral composition and structural texture given in the scenario

The core sample contains recrystallized calcite with a non-foliated interlocking texture.

Calcite (

CaCO_3

) is the diagnostic constituent mineral of carbonate rocks.

2

Identify the parent rock and metamorphic process

Thermal contact metamorphism of limestone/dolomite yields Marble.

Heat from igneous intrusions recrystallizes fine calcite shells/grains into coarse interlocking crystals without directed stress.

3

Evaluate the economic significance of the identified rock

Marble is mined for high-value building facades, monuments, and crushed industrial calcium carbonate.

Its aesthetic polish and chemical purity make it economically crucial in construction and chemical industries.

Key Concept

Metamorphic Protoliths, Thermal Transformation Processes, and Economic Mineral Uses

Question 120Question →

Match each Earth structural component or seismic boundary in Column I with its defining composition or physical behavior in Column II.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Conrad Discontinuity matches with the seismic boundary separating the upper granitic continental layer from the lower basaltic layer; Asthenosphere matches with the ductile, low-velocity mantle zone whose partial melting allows plastic deformation and lithospheric motion; Internal Mesosphere matches with the rigid, solid lower mantle region extending from the base of the asthenosphere to the outer core threshold; Gutenberg Discontinuity matches with the core-mantle boundary characterized by a sharp drop in compressional wave speed and complete cessation of shear waves.

The Conrad Discontinuity separates the granitic upper crust from the basaltic lower crust. The Asthenosphere is the partially molten upper mantle layer allowing tectonic flow. The Internal Mesosphere is the solid lower mantle. The Gutenberg Discontinuity marks the mantle-outer core interface where shear waves cannot propagate.

Step-by-Step Solution

1

Analyze intra-crustal and deep interior seismic discontinuities.

The Conrad boundary lies within continental crust between granitic sial and basaltic sima, while the Gutenberg boundary separates the rocky mantle from the liquid outer core where S-waves terminate.

Seismic discontinuities mark physical state transitions and compositional variations within the Earth.

2

Differentiate mechanical states across the mantle zones.

The upper mantle contains the ductile asthenosphere enabling lithospheric motion, whereas the lower mantle (internal mesosphere) remains solid despite elevated temperatures due to immense lithostatic pressure.

The physical state of Earth layers is dictated by the equilibrium between geothermal heat and confining pressure.

3

Pair each listed structural component with its precise geophysical characteristics.

Each Column I item accurately pairs with its corresponding Column II description.

Accurate pairing demonstrates advanced knowledge of Earth's internal division and seismic boundaries.

Key Concept

Internal Structure of the Earth and Seismic Discontinuities

Physical Geography

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