Day 16: Static Quiz on Geography

Solution: A Justification: The plates act like a hard and rigid shell compared to Earth’s mantle. This strong outer layer is called the lithosphere. Plate tectonics is the modern version of continental drift, a theory first proposed by scientist Alfred Wegener in 1912. Wegener didn’t have an explanation for how continents could move around the planet, but researchers do now. Plate tectonics is thus said to be the unifying theory of geology. The driving force behind plate tectonics is convection in the mantle. Hot material near the Earth’s core rises, and colder mantle rock sinks. In terms of analogy, it is kind of a pot boiling on a stove. The convection drive plates tectonics through a combination of pushing and spreading apart at mid-ocean ridges and pulling and sinking downward at subduction zones.

Solution: C
Justification: Plates are divided between major and minor plates based on their geographical coverage. The Indian plate is thus a major plate. So, (a) is correct. The subduction zone along the Himalayas forms the northern plate boundary in the form of continent convergence. So, (b) is correct. The peninsular plate is an integral part of the Indian plate. So, (c) is incorrect. In the east, it extends through the Rakinyoma Mountains of Myanmar towards the island arc along the Java Trench. The Western margin follows the Kirthar Mountain of Pakistan. So, (d) is correct

Solution: B
Justification: The lithosphere is broken into a number of plates known as the Lithospheric plates. The molten magma inside the earth moves in a circular manner. These plates move because of the movement of the molten magma inside the earth. Lateral movements between lithospheric plates create transform faults at the sites of plate slippage.

Solution: C
Justification: Iron makes up 5 percent of Earth’s crust and is second in abundance to aluminum among the metals and fourth in abundance behind oxygen, silicon, and aluminum among the elements. Iron, which is the chief constituent of Earth’s core, is the most abundant element in Earth as a whole (about 35 percent) and is relatively plentiful in the Sun and other stars. In the crust the free metal is rare, occurring as terrestrial iron

Solution: B
Justification: The most common chemical elements in the crust are oxygen (46.6%), silicon (27.7), aluminum (8.1), iron (5.0), calcium (3.6), potassium (2.8), sodium (2.6), and magnesium (2.1). Typical mantle rocks have higher magnesium to iron ratio and a smaller proportion of silicon and aluminum than the crust. The solid, inner core of the earth is iron and has a radius of about 760 miles. It is surrounded by a liquid, outer core composed of a nickel-iron alloy.

Solution: C
Justification: Statement 1: It is greater near the poles and less at the equator. This is because of the distance from the centre at the equator being greater than that at the poles.
Statement 2: Distribution of mass affects the effective mass that is applying the gravitational force. Since not
all earthly mass has the same density, there is bound to be a difference in the way gravitational force is experienced within the earth.

Solution: A
Justification: The annual variation of surface temperature in any ocean depends upon several factors, the most important among which are the annual variations of radiation income and the prevailing winds. The annual range over most of the oceans of the world is less than 5 oc. Maximum annual variations in the sea surface temperature occur generally in mid-latitude regions of the oceans. The ranges are generally greater close to the land, due to the land effect and are greater in the northern hemispheric oceans. The annual
range of surface temperature is much greater in the North Atlantic and North Pacific oceans than in the southern oceans. The high ranges in the northern oceans are associated with the character of the prevailing winds. In these parts of the oceans, cold winds blow from the continents toward the oceans and greatly reduce the winter temperatures. So, annual variations of up to 10c are found sometimes in these oceans due to low winter temperatures and high summer temperatures.

Solution: D
Justification: Positioned asymmetrically around the South Pole and largely south of the Antarctic Circle, Antarctica is the southernmost continent and is surrounded by the Southern Ocean. Alternatively, it may be considered to be surrounded by the Southern Pacific, Atlantic, and Indian Oceans, or by the southern waters of the World Ocean.

Solution: B
Justification: Examples of fossils include bones, shells, exoskeletons, stone imprints of animals or microbes, hair, petrified wood, oil, coal, and DNA remnants. In igneous rocks that are made entirely of lava deposits, or in metamorphic rocks that may be buried deep beneath the earth, these are hard to find. These are best preserved in sedimentary rocks that are layered rocks containing evidence of the evolution of life on earth. Metamorphic rocks sometimes contain fossils if they were formed from a sedimentary rock, but the fossils
are usually squashed out of shape. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ages of rocks and the fossils they host.

Solution: C
Justification: Sediment Maturity refers to the length of time that the sediment has been in the sedimentary cycle. Texturally mature sediment is sediment that is well rounded, (as rounding increases with transport distance and time) and well sorted (as sorting gets better as larger clasts are left behind and smaller clasts are carried away. If the fragments are angular, it indicates that they have not been transported very far and the sediment is poorly sorted.