SOLUTIONS – INSIGHTS REVISION TEST for Preliminary Exam 2018: Test – 38(Geography)

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SOLUTIONS

INSIGHTS REVISION TEST for Preliminary Exam 2018: Test – 38(Geography)


                          

  1. Which of the following statement is NOT correct

a) The seismograph provides information regarding time, location and magnitude of the earthquake.

b) The seismographs located beyond 145’ from epicenter record the arrival of P-waves only.

c) At a seismic station the first waves to arrive are surface waves.

d) The intensity of an earthquake is measured by Mercalli scale.

 

Answer: (c)

Justification:

Seismic waves are the vibrations from earthquakes that travel through the Earth; they are recorded on instruments called seismographs. Seismographs record a zig-zag trace that shows the varying amplitude of ground oscillations beneath the instrument. Sensitive seismographs, which greatly magnify these ground motions, can detect strong earthquakes from sources anywhere in the world. The time, location, and magnitude of an earthquake can be determined from the data recorded by seismograph stations.

S waves shadow zone extend from 105. P wave shadow zone extends between 105⁰ to 145⁰. Beyond 145⁰ only P waves are received

At seismic station first waves to arrive are P waves. Then S waves and in the last the surface waves.


2.Consider the following statements regarding Plate Tectonics

  1. Oceanic trenches are morphological feature of divergent plate boundaries.
  2. Plate movement along transform boundaries leads to formation of fold mountains.

 

Which of the following is/are CORRECT

a) 1 only

b) 2 only

c) Both 1 and 2

d) None of the above

Answer: (d)

Justification:

Oceanic trenches are morphological feature of Convergent plate boundaries. For e.g Mariana trench along subduction zone of Philippines plate and Pacific plate

Because of sliding movement along transform boundaries only high intensity earthquakes are possible. It does not lead to mountain orogeny. E.g San Andreas Fault


  1. The most violent volcanic eruptions are associated with which of the following volcano

a) Shield Volcanoes

b) Caldera

c) Mid-Ocean Ridge volcanoes

d) Flood Basalt Provinces

Answer: (b)

Justification:

Caldera volcanoes are the Extreme Volcanoes. These are the most powerful and catastrophic types of volcanoes in a category by themselves because of the unique way in which they form. This type of volcano is shaped more like an inverse volcano. An enormous magma chamber bulges up beneath the ground from the extremely high pressures of the trapped gases within. Ring-shaped cracks form outward from the magma chamber toward the surface and these act as relief valves for the magma to escape. Once the accumulated pressure has been sufficiently released through a serious of extremely powerful pyroclastic and plinian eruptions, the ground above the magma chamber subsides or caves in, leaving a large depression.

In Shield volcano, Mid-ocean ridges and Flood basalt provinces the lava is not much viscous because of basaltic composition. The eruptions are not violent


4.Indicate the correct sequence of Igneous, sedimentary and Metamorphic rocks based on the following statements

  1. The rocks are stratified rocks rich in fossils of animals and plants.
  2. The rocks are hard and normally crystalline in structure.
  3. Rocks undergo chemical changes or structural modification of minerals because of excessive heat and pressure.

 

Which of the following is correct

a) 3,2,1

b) 1,2,3

c) 2,1,3

d) 1,3,2

 

Answer: (c)

Justification:

Igneous rock is formed when magma or lava from volcanoes cools. Examples include basalt and granite. Most igneous rock is very hard. They are normally crystalline in structure.They do not occur in strata

Sedimentary rocks are formed over millions of years when sediments (tiny pieces of rocks and animal skeletons) are pressed together at the bottom of seas and rivers.They are distinguished from other rock types in their characteristic layer formation and are termed stratified rocks. Examples include sandstone, coal and chalk. Some sedimentary rocks contain fossils (bones or shells of living things that were buried long ago and have turned to stone).

Metamorphic rocks are formed when other rocks are changed due to heat or pressure. Examples include slate and marble. Metamorphic rocks are very hard but can be damaged by acids like acid rain (on buildings) or even lemon juice (on worktops!).


 

5 . A meandering stream deposit most of its sediments

a) Inside of the meanders where the stream flows faster

b) Inside of the meanders where the stream flows slower

c) Outside of meanders where the stream flows faster

d) Outside of meanders where the stream flows faster

 

Answer: (b)

Justification:

 


 

6.The boundary between the crust and mantle

a) is a source region where earth’s magnetic field is formed

b) coincides with the boundary between the asthenosphere and lithosphere

c) is marked by a change in velocity of seismic waves at the Moho.

d) None of the above

 

Answer: (c)

Justification:

The source region for formation of magnetic field is core of the earth

Asthenosphere and outer outer mantle are part of mantle. Lithosphere includes a part of outer mantle.

Seismic wave diffraction shows a boundary between more and less dense rocks that is commonly taken to be the crust-mantle boundary. It’s called the Mohorovicic discontinuity or Moho for short. It’s usually at 30-40 km depth underneath continents, but can be as deep as 80 km.

 


  1. Which of the following statements is CORRECT

(a) The Earth’s magnetic poles are inclined approximately 11 degrees from the Earth’s rotation axis.

(b) The Earth’s magnetic poles are aligned with Earth’s rotation axis.

(c) The Earth’s magnetic poles are perpendicular to the Earth’s rotation axis.

(d) None of the above.

Answer: (a)

Justification:

 


  1. The boundary zone between Pacific plate and Antarctic plate exhibits conditions of

                (a) convergence

                (b) sinking

                (c) sliding

                (d) divergence

                Answer: (d)

                Justification :

            


   

  1. A lens-shaped igneous intrusion situated beneath an anticlinal fold or in the base of a syncline is called

                (a) Lapolith

                (b) Lacolith

                (c) Phacolith

                (d) Batholith

                Answer: (c)

                Justification:

Batholith, is large body of intrusive igneous rock believed to have been crystallized at the considerable depth below the earth’s surface.. They are the largest type of pluton. Example of batholith is Idaho batholith which cover surface area of over 15500 kilometer square.
Lopolith these are saucer – shaped features formed beneath the earth’s surface through magma intrusion. Lopolith forms great shallow basin when magma solidifies within the crust a good example is bush veld igneous complex of South Africa which is composed of both granite and basic rock.

Laccolith, this is a sheet intrusion that has been injected between two layers of sedimentary rock. The pressure of magma is powerful enough that the overlying strata are forced upward giving laccolith a dome or mushroom like form with generally planar base. Some laccolith can be found in Madagascar and Utah USA where they has been exposed by erosion.

Phacolith, this is lens shaped pluton that occupy either the crest of an anticline or trough of syncline. A good example of phacolith can be seen seen in Corndon hills in Shropshire United Kingdom.


  1. Match the following

               Landforms                       Processes

      A . Natural Levees                    1. Aeolin

     B. Esker                                   2. Karst

     C.  Uvala                                  3. Fluvial

     D. Barchan                               4. Glacial

 Which of the following is correct

        A     B    C    D

a)     1     3     2    4

b)     3     2     4    1

c)     1     2     3    4

d)     3     4     2    1

 

Answer: (d)

 

Justification:

Natural Levees    – Fluvial

Esker                  – Glacial

Uvala                 – Karst

Barchan             – Aeolin


  1. Dead sea is situated in which one of the following

  (a) A rift valley

  (b) An intermontane Plateau

  (c) Intermontane Plains

  (d) Canyons

Answer: (a)

Justification:

The Dead Sea Transform (DSTfault system, also sometimes referred to as the Dead Sea Rift, is a series of faults that run from the Maras Triple Junction (a junction with the East Anatolian Fault in southeastern Turkey) to the northern end of the Red Sea Rift (just offshore of the southern tip of the Sinai Peninsula). The fault system forms the transform boundary between the African Plate to the west and the Arabian Plate to the east.

 


  1. Hawaii Islands are known for active volcanoes because

  (a) they are locked in the subduction zone of covering

  (b) faults and fractures are found there

  (c) they are situated over a hot plume

  (d) they are situated on a diverging boundary with rising convective currents

Answer: (c)

Justification:

The Earth’s outer crust is made up of a series of tectonic plates that move over the surface of the planet. In areas where the plates come together, sometimes volcanoes will form. Volcanoes can also form in the middle of a plate, where magma rises upward until it erupts on the seafloor, at what is called a “hot spot.”

The Hawaiian Islands were formed by such a hot spot occurring in the middle of the Pacific Plate. While the hot spot itself is fixed, the plate is moving. So, as the plate moved over the hot spot, the string of islands that make up the Hawaiian Island chain were formed.


13.Consider the following

  1. Nearly 46.6% of total crust of earth is composed of silicon.
  2. P wave travel fastest through inner core.

   Which of the following is correct

a) 1 only

b) 2 only

c) Both 1 and 2

d) None of the above

 

Answer: (d)

Justification:

Nearly 46.6% of total crust of earth is composed of oxygen and 27.72% by silicon

The P waves travel fastest through outer mantle. Seismic velocities depend on the material properties such as composition, mineral phase and packing structure, temperature, and pressure of the media through which seismic waves pass.

Seismic waves travel more quickly through denser materials and therefore generally travel more quickly with depth. Anomalously hot areas slow down seismic waves. Seismic waves move more slowly through a liquid than a solid.

Molten areas within the Earth slow down P waves and stop S waves because their shearing motion cannot be transmitted through a liquid. Partially molten areas may slow down the P waves and attenuate or weaken S waves.


 

  1. The common weathering found in hot and dry environment is

                (a) Carbonation

                (b) Hydration

                (c) Abrasion

                (d) Frost action

                Answer: (c)

                Justification :

In desert and arid regions wind is an important agent of weathering. Abrasion through wind action is important mode of erosion.

                Carbonation and hydration are more common in humid areas

                Frost action is common in tundra and temperate regions.

 


  1. Which one of the following is NOT correctly matched

                (a) Washington  :  Potomac river

                (b) Vienna           :  Danube river

                (c) Canberra        : Murray river

                (d) Lahore          : Ravi river

                Answer: (c)

                Justification:

                Canberra is located on Murrumbidgee river


16.Consider the following statements

  1. The flow of Mississippi river is entirely located in USA.
  2. River Parana flows through Pampas region of South America.

    Which of the following statement is/are correct

a) 1 only

b) 2 only

c) Both 1 and 2

d) None of the above

 

Answer: (c)

 


  1. Aral sea is located between

                (a) Uzbekistan and Turkmenistan

                (b) Uzbekistan and Kazakhstan

                (c) Kazakhstan and Tajikistan

                (d) Tajikistan and Kyrgyzstan

Answer: (b)


  1. All Central American countries are located along both coasts of Caribbean Sea and Pacific Ocean EXCEPT

                (a) Nicaragua and Honduras

                (b) Panama and Costa Rica

                (c) Belize and El Salvador

                (d) None of the above

Answer: (c)


  1. English Channel is separated by North Sea by

                (a) Strait of Otranto

                (b) Strait of Gibraltar

                (c) Strait of Dardanelles

                (d) Strait of Dover

Answer: (d)


  1. Beginning from Perth encircling Australia, various geographical features one comes across in order are

                (a) Great Barrier Reef – Bass Strait – Torres Strait

                (b) Bass strait – Great Barrier Reef – Torres Strait

                (c) Torres Strait – Bass Strait – Great Barrier Reef

                (d) Great Barrier Reef – Torres Strait – Bass Strait

                Answer: (b)