Chapter 1: Origin and Structure of the Ear (Set-2)
The nebular hypothesis explaining the origin of the solar system mainly emphasizes the role of which fundamental process in transforming a gaseous mass into planets and the Sun
A Sudden explosion of matter
B Gradual cooling and condensation
C Continuous volcanic outpouring
D Random collision of stars
The nebular hypothesis states that the solar system formed from a rotating cloud of gas and dust. Gradual cooling led to condensation, forming the Sun at the center and planets from the remaining material.
Which characteristic of the Sun best explains its dominant gravitational control over all planets in the solar system
A Its extremely high surface temperature
B Its continuous nuclear fusion reactions
C Its massive size and concentration of matter
D Its emission of solar winds
The Sun contains more than 99 percent of the total mass of the solar system. This enormous mass creates strong gravitational attraction, enabling it to control planetary orbits effectively.
The tidal hypothesis proposed by Jeans and Jeffreys explains the origin of planets as a result of
A Cooling of a rotating nebula
B Accretion of cosmic dust
C Ejection of matter due to stellar attraction
D Collision between two galaxies
According to the tidal hypothesis, a nearby passing star exerted tidal forces on the Sun, pulling out solar material which later condensed to form planets.
Earth’s rotation is directly responsible for which of the following observable geographical phenomena
A Seasonal variation in climate
B Difference in length of day and night
C Occurrence of day and night
D Change in wind direction annually
Earth rotates on its axis once every 24 hours. This rotation causes alternating exposure to sunlight and darkness, resulting in the regular cycle of day and night.
The phenomenon of seasons on Earth is mainly caused by
A Elliptical shape of Earth’s orbit
B Distance between Earth and Sun
C Inclination of Earth’s axis
D Variable speed of Earth’s rotation
Earth’s axis is tilted at about 23½ degrees. This tilt causes different hemispheres to receive varying solar radiation throughout the year, producing seasonal changes.
Which imaginary line divides the Earth into Northern and Southern Hemispheres and serves as the reference for latitude
A Prime Meridian
B International Date Line
C Tropic of Cancer
D Equator
The Equator is an imaginary line at 0° latitude. It divides Earth into Northern and Southern Hemispheres and serves as the base for measuring all latitudes.
Longitudes are primarily used for which geographical purpose
A Measuring distance from the Equator
B Determining climatic zones
C Calculating local time
D Identifying landforms
Longitudes measure angular distance east or west of the Prime Meridian. Since Earth rotates 15 degrees per hour, longitudes are essential for calculating local and standard time.
The Prime Meridian passes through which internationally recognized location
A Paris Observatory
B Greenwich Observatory
C International Date Line
D Equator at Africa
The Prime Meridian at 0° longitude passes through Greenwich Observatory in England. It is the internationally accepted reference for measuring longitudes and global time.
Which layer of the Earth is mainly composed of nickel and iron and has extremely high temperature and pressure
A Crust
B Mantle
C Outer core
D Inner core
The inner core consists primarily of nickel and iron, known as nife. Despite extremely high temperatures, immense pressure keeps it in a solid state.
The mantle is distinguished from the crust mainly due to
A Complete absence of minerals
B Higher density and temperature
C Liquid nature of rocks
D Presence of oceans
The mantle lies beneath the crust and contains denser materials. Temperature and pressure increase with depth, making mantle rocks hotter and heavier than crustal rocks.
Which evidence strongly supported Wegener’s Continental Drift Theory related to biological similarities
A Matching mountain ranges
B Similar fossil distribution
C Ocean floor symmetry
D Magnetic anomalies
Wegener cited identical fossils found on widely separated continents. These similarities suggested that continents were once joined and later drifted apart over geological time.
The main limitation of Wegener’s Continental Drift Theory was its inability to explain
A Past climatic changes
B Matching coastlines
C Mechanism of continental movement
D Fossil similarities
Although Wegener presented strong evidences, he could not satisfactorily explain the force or mechanism responsible for the movement of continents across ocean floors.
Plate tectonic theory improved upon continental drift by introducing the concept of
A Fixed continents
B Convection currents in mantle
C Earth expansion
D Static ocean basins
Plate tectonic theory explains continental movement through convection currents in the mantle, which drive lithospheric plates and provide a scientific mechanism absent in Wegener’s theory.
Which type of plate boundary is most commonly associated with volcanic activity and mid-ocean ridges
A Convergent boundary
B Transform boundary
C Divergent boundary
D Conservative boundary
Divergent boundaries occur where plates move apart. Magma rises to fill the gap, creating new crust and resulting in volcanic activity and mid-ocean ridges.
Earthquakes occur mainly due to
A Volcanic eruptions alone
B Sudden release of energy along faults
C Atmospheric pressure changes
D Ocean current movements
Earthquakes result from the sudden release of accumulated stress along fault lines in the Earth’s crust, generating seismic waves that cause ground shaking.
The point inside the Earth where an earthquake originates is known as
A Epicenter
B Focus
C Fault plane
D Seismic zone
The focus or hypocenter is the actual point within the Earth where seismic energy is released. The epicenter lies directly above it on the surface.
Volcanoes are most commonly located
A At the center of continents
B Along plate boundaries
C Near river basins
D At polar regions
Most volcanoes occur along plate boundaries where tectonic activity allows magma to rise to the surface, especially at convergent and divergent margins.
Folding of rocks is primarily caused by
A Tensile forces
B Volcanic eruptions
C Compressional forces
D Weathering processes
Folding occurs when compressional forces act on rock layers, causing them to bend rather than break, commonly seen in mountain-building regions.
Faulting differs from folding because faulting involves
A Bending of rock layers
B Breaking and displacement of rocks
C Chemical weathering
D Sediment deposition
Faulting occurs when rocks fracture due to stress and move along a plane. Unlike folding, it involves breaking rather than bending of rock layers.
Igneous rocks are formed through the process of
A Sedimentation
B Metamorphism
C Cooling and solidification of magma
D Compaction of sediments
Igneous rocks originate from molten magma or lava. When this molten material cools and solidifies, it forms igneous rocks, either intrusive or extrusive.
Which igneous rock is coarse-grained due to slow cooling beneath Earth’s surface
A Basalt
B Granite
C Pumice
D Obsidian
Granite forms deep inside the Earth where magma cools slowly. This slow cooling allows large crystals to develop, giving granite a coarse-grained texture.
Sedimentary rocks are particularly important for human civilization because they
A Are hardest rocks
B Contain fossils and mineral fuels
C Originate from magma
D Are resistant to erosion
Sedimentary rocks preserve fossils and contain resources like coal, petroleum, and natural gas. These features make them significant for studying Earth’s history and economic use.
Metamorphic rocks are formed when existing rocks undergo changes due to
A Weathering and erosion
B Deposition and compaction
C Heat and pressure
D Volcanic explosions
Metamorphic rocks form when pre-existing rocks are subjected to intense heat and pressure, causing physical and chemical changes without complete melting.
Which rock transformation best represents the rock cycle
A Granite directly changing into basalt
B Sandstone changing into marble
C Limestone changing into marble
D Basalt changing into coal
Limestone transforms into marble through metamorphism under heat and pressure. This example clearly demonstrates rock cycle processes involving sedimentary to metamorphic change.
The asthenosphere plays a crucial role in plate tectonics because it
A Forms the Earth’s core
B Is rigid and immobile
C Allows plates to move
D Stores groundwater
The asthenosphere is a semi-molten layer beneath the lithosphere. Its plastic nature allows tectonic plates to float and move, enabling plate tectonic activity.
Which seismic waves are the fastest and first to be recorded during an earthquake
A Surface waves
B Love waves
C Secondary waves
D Primary waves
Primary waves, or P-waves, travel fastest through solid, liquid, and gaseous materials. They are the first seismic waves detected by seismographs after an earthquake.
The Mohorovičić discontinuity separates the
A Mantle and core
B Crust and mantle
C Outer and inner core
D Lithosphere and asthenosphere
The Mohorovičić discontinuity, or Moho, marks the boundary between Earth’s crust and mantle, identified by a sudden change in seismic wave velocity.
The direction of Earth’s rotation is from
A North to South
B West to East
C East to West
D South to North
Earth rotates from west to east, which causes the Sun to appear to rise in the east and set in the west, influencing time differences globally.
Which phenomenon provides evidence for Earth’s rotation
A Seasonal rainfall
B Coriolis effect
C Tidal variation
D Plate movement
The Coriolis effect results from Earth’s rotation, causing deflection of winds and ocean currents. This phenomenon confirms that Earth is rotating on its axis.
Which type of rock is most susceptible to weathering due to layered structure
A Igneous
B Metamorphic
C Sedimentary
D Plutonic
Sedimentary rocks are formed in layers and are often less compact. This layered structure makes them more vulnerable to weathering and erosion processes.
The lithosphere includes
A Only the crust
B Crust and upper mantle
C Mantle and core
D Only oceanic crust
The lithosphere consists of Earth’s crust and the rigid upper part of the mantle. It is broken into tectonic plates that move over the asthenosphere.
Oceanic crust is generally thinner and denser than continental crust because it is mainly composed of
A Granite
B Basalt
C Limestone
D Quartz
Oceanic crust is composed largely of basalt, a dense igneous rock. This makes it thinner and heavier compared to continental crust, which is granitic.
Which force is mainly responsible for the movement of tectonic plates
A Gravitational pull of Moon
B Solar radiation
C Mantle convection currents
D Earth’s magnetic field
Heat from Earth’s interior creates convection currents in the mantle. These currents exert force on lithospheric plates, driving their continuous movement.
Rift valleys are formed mainly due to
A Compression and folding
B Volcanic deposition
C Tensional forces and faulting
D Sediment accumulation
Rift valleys form when tensional forces pull the crust apart, causing blocks to subside between parallel faults, as seen in the East African Rift Valley.
Which rock is formed from volcanic lava cooling rapidly on the surface
A Granite
B Gabbro
C Basalt
D Diorite
Basalt is an extrusive igneous rock formed when lava cools rapidly on Earth’s surface. Rapid cooling results in fine-grained texture.
The core of the Earth is primarily responsible for
A Formation of mountains
B Generation of magnetic field
C Plate movement
D Weather phenomena
The Earth’s magnetic field is generated by the movement of molten iron in the outer core. This geodynamo effect protects Earth from harmful solar radiation.
Which latitude marks the region receiving maximum direct sunlight throughout the year
A Tropic of Cancer
B Tropic of Capricorn
C Arctic Circle
D Equator
The Equator receives nearly vertical sun rays throughout the year. This results in consistently high temperatures and minimal seasonal variation.
Subduction zones are created when
A Two plates move apart
B Two continental plates collide
C Oceanic plate sinks beneath continental plate
D Plates slide past each other
In subduction zones, denser oceanic plates sink beneath lighter continental plates. This process leads to deep-sea trenches, earthquakes, and volcanic arcs.
Which type of earthquake is caused by human activities such as mining and reservoir construction
A Tectonic earthquakes
B Volcanic earthquakes
C Collapse earthquakes
D Induced earthquakes
Induced earthquakes result from human activities that alter stress conditions in the Earth’s crust, such as mining, fluid injection, and large dam construction.
The rigidity of rocks generally increases with
A Increase in temperature
B Increase in pressure
C Increase in erosion
D Increase in moisture
As depth increases, pressure rises, making rocks more rigid. High pressure resists deformation, even though temperature also increases within the Earth.
Which evidence supports sea-floor spreading theory
A Fossil similarities
B Symmetrical magnetic patterns
C Fold mountains
D Glacial deposits
Magnetic stripes on the ocean floor show symmetrical patterns on either side of mid-ocean ridges, indicating new crust formation and supporting sea-floor spreading theory.
The epicenter of an earthquake is best defined as
A Deepest point of rupture
B Point of maximum damage inside Earth
C Surface point directly above focus
D Boundary of seismic waves
The epicenter is the point on Earth’s surface directly above the focus. It generally experiences the strongest shaking during an earthquake.
Which rock is commonly used in construction due to its hardness and durability
A Shale
B Limestone
C Granite
D Sandstone
Granite is a hard, durable igneous rock resistant to weathering. These properties make it suitable for construction, monuments, and flooring purposes.
The Tropic of Cancer is significant because
A It marks polar night
B It receives overhead Sun once a year
C It divides hemispheres
D It marks longest day
The Tropic of Cancer at 23½°N marks the northernmost position of the overhead Sun during the June solstice, influencing seasonal climate patterns.
Which type of plate boundary produces neither crust nor destroys it
A Divergent
B Convergent
C Transform
D Destructive
At transform boundaries, plates slide past each other horizontally. No new crust is created or destroyed, but earthquakes are common due to friction.
Which rock type forms the foundation of continental crust
A Basalt
B Granite
C Marble
D Slate
Continental crust is primarily granitic in composition. Granite is lighter and less dense than basalt, allowing continents to remain elevated above oceanic crust.
The average thickness of continental crust is greater than oceanic crust mainly because
A It is younger
B It is denser
C It resists subduction
D It is basaltic
Continental crust is less dense and more buoyant, preventing easy subduction. This allows it to remain thicker and older compared to oceanic crust.
Which movement of Earth is responsible for variation in length of day and night
A Rotation only
B Revolution only
C Rotation and axial tilt
D Revolution and rotation
While rotation causes day and night, axial tilt leads to variation in daylight duration across seasons and latitudes, especially noticeable away from the Equator.
Which rock type is most likely to preserve fossils
A Igneous
B Metamorphic
C Sedimentary
D Volcanic
Sedimentary rocks form through deposition under low temperature and pressure conditions, allowing organic remains to be preserved as fossils over geological time.
The study of earthquakes is scientifically known as
A Geomorphology
B Seismology
C Petrology
D Climatology
Seismology is the scientific study of earthquakes and seismic waves. It helps in understanding Earth’s internal structure and assessing earthquake hazards.