1. Which of the following are considered the "Relief Features of the First Order" on the Earth's surface?
a) Mountains and Plains
b) Plateaus and Valleys
c) Continents and Ocean Basins
d) Mid-oceanic Ridges and Trenches
Answer: c) Continents and Ocean Basins
In geomorphology, Continents and Ocean basins are classified as First Order Relief Features. Mountains and plains belong to the second order.
2. Who proposed the Continental Drift Theory?
(a) Arthur Holmes
(b) Alfred Wegener
(c) Harry Hess
(d) J. Tuzo Wilson
Answer: (b) Alfred Wegener
Alfred Wegener proposed the Continental Drift Theory in 1912 and published it in The Origin of Continents and Oceans (1915).
As per the continental drift theory, there was a supercontinent named Pangaea, meaning "All Earth," and it was surrounded by the universal ocean called Panthalassa.
Later, Pangaea split into northern (Laurasia) and southern (Gondwanaland) landmasses, separated by the ancient Tethys Sea. These pieces gradually drifted to their current positions of continents and oceans.
3. Which scientist proposed the Convection Current Theory?
(a) Harry Hess
(b) Alfred Wegener
(c) Arthur Holmes
(d) Dana
Answer: (c) Arthur Holmes
Arthur Holmes (1929) suggested that mantle convection currents are responsible for continental movement.
Holmes suggested that the decay of radioactive elements deep within the Earth generates intense heat. This led to less dense rock rising toward the crust, moving horizontally as it cools, and sinking back down. This is like a "conveyor belt".
4. The Sea Floor Spreading Theory was proposed by:
(a) Alfred Wegener
(b) Arthur Holmes
(c) Harry Hess
(d) Le Pichon
Answer: (c) Harry Hess
Harry Hess (1960–62) proposed that new oceanic crust is formed at mid-oceanic ridges and spreads outward.
5. Which evidence strongly supported the Sea Floor Spreading Theory?
(a) Fossils of Mesosaurus
(b) Jigsaw fit of continents
(c) Magnetic striping on the ocean floor
(d) Tillite deposits
Answer: (c) Magnetic striping on the ocean floor
Symmetrical magnetic bands on either side of mid-oceanic ridges provided strong evidence for sea-floor spreading.
6. Which theory is the most widely accepted theory regarding the origin and movement of continents and ocean basins?
(a) Continental Drift Theory
(b) Geosynclinal Theory
(c) Plate Tectonic Theory
(d) Contraction Theory
Answer: (c) Plate Tectonic Theory
Plate Tectonics integrates continental drift, sea-floor spreading, earthquakes, volcanoes, and mountain building into a single framework.
7. Which of the following is an example of a divergent plate boundary?
(a) Himalayas
(b) Andes Mountains
(c) Mid-Atlantic Ridge
(d) San Andreas Fault
Answer: (c) Mid-Atlantic Ridge
At divergent boundaries, plates move apart, and new oceanic crust is formed. The Mid-Atlantic Ridge is the world's best example.
8. The Wilson Cycle explains:
(a) Evolution of stars
(b) Evolution of ocean basins
(c) Formation of the Moon
(d) Atmospheric circulation
Answer: (b) Evolution of ocean basins
J. Tuzo Wilson explained the opening and closing of ocean basins through the Wilson Cycle.
9. Which of the following statements is/are correct regarding the 'Seafloor Spreading Theory'?
1. Rocks closer to the mid-oceanic ridges are younger and have normal magnetic polarity
2. The oceanic crust is significantly older than the continental crust
Select the correct option:
a) 1 only
b) 2 only
c) Both 1 and 2
d) Neither 1 nor 2
Answer: a) 1 only
Statement 1 is correct because new crust is constantly emerging at the ridge.
Statement 2 is incorrect because the oceanic crust is much younger than the continental crust. Oceanic crust is continuously destroyed at subduction zones and rarely exceeds 200 million years in age, while continental rocks can be billions of years old.
10. Regarding plate tectonics, consider the following statements:
1. The plates move over the asthenosphere.
2. New crust is generated at divergent boundaries.
Select the correct option:
a) 1 only
b) 2 only
c) Both 1 and 2
d) Neither 1 nor 2
Answer. c) Both 1 and 2
Both statements are correct.
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