Exp) Hardness is the relative resistance being scratched; ten minerals are selected to measure the degree of hardness from 1-10. They are:

1. talc;

2. gypsum;

3. calcite;

4. fluorite;

5. apatite;

6. feldspar;

7. quartz;

8. topaz;

9. corundum;

10. diamond.

Compared to this for example, a fingernail is 2.5 and glass or knife blade is 5.5.

Source) FUNDAMENTALS OF PHYSICAL GEOGRAPHY; Chapter 5; page number 41

Exp) Statement 1 is correct. The lava that is released during volcanic eruptions on cooling develops into igneous rocks. The cooling may take place either on reaching the surface or also while the lava is still in the crustal portion. Depending on the location of the cooling of the lava, igneous rocks are classified as volcanic rocks (cooling at the surface) and plutonic rocks (cooling in the crust). The lava that cools within the crustal portions assumes different forms. These forms are called intrusive forms. Hence, statement 2 is incorrect.

Source) FUNDAMENTALS OF PHYSICAL GEOGRAPHY; chapter 5; page number 42

Exp) All the statements are incorrect.

Cement is a mixture of non-metallic minerals. Non-Metallic Minerals do not contain metal content. Sulphur, phosphates and nitrates are examples of non-metallic minerals.

Mica forms 4 per cent of the earth’s crust. It is commonly found in igneous and metamorphic rocks. It is used in electrical instruments.

A mineral is composed of two or more elements. But, sometimes single element minerals like sulphur, copper, silver, gold, graphite etc. are found.

Source) FUNDAMENTALS OF PHYSICAL GEOGRAPHY; chapter 5; page number 42

Exp) All are responsible for the formation of lakes on the earth’s surface.

When the glaciers melted, water filled those depressions, forming lakes. Glaciers also carved deep valleys and deposited large quantities of earth, pebbles, and boulders as they melted. These materials sometimes formed dams that trapped water and created more lakes.

Some lake basins form where plate tectonics changed the Earth’s crust, making it buckle and fold or break apart. When the crust breaks, deep cracks, called faults, may form. These faults make natural basins that may fill with water from rainfall or from streams flowing in the basin. When these movements occur near the ocean, part of the ocean may be trapped by a new block of land thrust up from below the Earth’s surface.

Many lakes form as a result of volcanoes. After a volcano becomes inactive, its crater may fill with rain or melted snow. Sometimes the top of a volcano is blown off or collapses during an eruption, leaving a depression called a caldera. It, too, may fill with rainwater and become a lake.

Lakes may also be created by landslides or mudslides that send soil, rock, or mud sliding down hills and mountains. The debris piles up in natural dams that can block the flow of a stream, forming a lake.

Source) GC Leong; Chapter 4

Exp)  The Karst region is an example of Limestone and Chalk Landform with a large stretch of limestone. This regions have a bleak landscape, occasionally broken by precipitous slopes. There is a general absence of surface drainage as most of the surface water has gone underground. In this region, streams rising on other rocks only flow over limestone for a short distance and then disappear underground.

Source) GC Leong; Chapter 8

Exp) The sand-blasting of rock surfaces by winds when they hurl sand particles against them is called abrasion. The impact of such blasting result in rock surfaces being scratched, polished and worn away. Abrasion is most effective at or near the base of rocks, where the amount of material the wind is able to carry is greatest. Therefore, tele-graph poles in the deserts are protected by a covering of metal for a foot or two above the ground. 

Deflation: This process involves the lifting and blowing away of loose materials such as sands, pebbles from the ground. The finer dust and sands may be removed miles away from their place of origin, and be deposited even outside the desert margins. This process results in lowering of the land surface to form large depressions called deflated hollows.

Attrition: when wind-borne particles roll against one another in collision they wear each other away so that their sizes are greatly reduced and grains are rounded into millet seed sand.

Source) GC Leong; Chapter 7; page number 56

Exp) Statement 1 is correct. Emergence of a ‘U’-shaped valley marks the beginning of old age. The glacier on its downward journey begins to wear away the sides and floor of the valley down which it moves. It scratches and grinds the bedrock, removing any rock debris and surface soil. An outwash plain with features such as eskers, kame terraces, drumlins, kettle holes etc. is a prominent development of glaciated lowlands.

Statement 2 is incorrect. Hanging valleys start emerging at the mature stage of a glacier. In this stage, the main valley is eroded much more rapidly than tributary valleys as it contains a much larger glacier. After the ice has melted a tributary valley therefore 'hangs' above the main valley so that its stream plunges down as waterfall. Such tributary valleys are termed hanging valleys.

The youth stage of a glacier is marked by the inward cutting activity of ice in a cirque.

Source) GC Leong; Chapter 5; page 50

FUNDAMENTALS OF PHYSICAL GEOGRAPHY; page number 68

Exp) Plains are by far the most prominent landforms in the deserts. In basins with mountains and hills around and along, the drainage is towards the centre of the basin and due to gradual deposition of sediment from basin margins, a nearly level plain forms at the centre of the basin. In times of sufficient water, this plain is covered up by a shallow water body. Such types of shallow lakes are called as playas where water is retained only for short duration due to evaporation and quite often the playas contain good deposition of salts. The playa plain covered up by salts is called alkali flats.

The Didwana lake (playa)located in the eastern part of the Thar desert supports commercial salt production.

Source) FUNDAMENTALS OF PHYSICAL GEOGRAPHY; chapter 7; page number 72

http://www.geosocindia.org/index.php/jgsi/article/view/58026

• Option C is the Correct Answer: 
  • Cirques are deep, long and wide troughs or basins with very steep concave to vertically dropping high walls at its head as well as sides. They are simply a bowl-shaped depression formed due to the erosional activity of glaciers.
  • Moraines are long ridges of deposits of glacial till. When these deposits are at the end of a glacier, they are called Terminal moraines and when they are deposited on both sides, they are called Lateral moraines.
  • A bergschrund or rimaye is a crevasse that forms where the moving glacier ice separates from the stagnant ice or firn above.
• Barkhan, also spelt Barkhan, crescent-shaped sand dune produced by the action of wind predominately from one direction. 

• Option D is the Correct Answer:
• Parent Material: It is deposited by streams or derived from in-situ weathering. In this stage, soil inherits many properties like the mineral composition, the colour, the particle size and the chemical elements. For example- Black soil-derived its colour from lava rock.
• Climate: It is one of the important factors in the formation of soil because it affects the rate of weathering of the parent rock.
• Topography (Relief, Altitude and Slope): It is considered as a passive factor to modifying the effects of climate because it affects soil processes, soil distribution and the type of vegetation.
• Biological Activity: Biological Activity, in conjunction with climate, modifies parent material to produce soil. For Example- Leguminous plants (such as beans, peas, and groundnuts) have nitrogen-fixing bacteria. These plants take the nitrate ions directly from these nitrogen-fixing bacteria. It improves the fertility of the soil by fixing atmospheric nitrogen to ammonia or ammonium.
• Time: The formation of the soil is not one day process but requires many years to form. Younger soils have some characteristics from their parent material, but as they age, the addition of organic matter, exposure to moisture and other environmental factors may change its features.

Explanation:

• Pair 1 is Correct: Weathering is the action of elements of weather and climate over earth material. It can be defined as mechanical disintegration and chemical decomposition of rocks through the actions of various elements of weather and climate.
• Pair 2 and 3 is Incorrect: Mass movements transfer the mass of rock debris down the slope under the direct influence of gravity. Mass movements are very active over weathered slopes rather than over unweathered slopes. Erosion is the acquisition and transportation of rock debris by geomorphic agents like running water, wind, waves etc. A deposition is a consequence of erosion. The erosional agents lose their velocity and energy on gentle slopes and materials carried by them start to settle themselves.

Explanation:

• Pair 1 is Correct: Weathering is the action of elements of weather and climate over earth material. It can be defined as mechanical disintegration and chemical decomposition of rocks through the actions of various elements of weather and climate.
• Pair 2 and 3 is Incorrect: Mass movements transfer the mass of rock debris down the slope under the direct influence of gravity. Mass movements are very active over weathered slopes rather than over unweathered slopes. Erosion is the acquisition and transportation of rock debris by geomorphic agents like running water, wind, waves etc. A deposition is a consequence of erosion. The erosional agents lose their velocity and energy on gentle slopes and materials carried by them start to settle themselves.

Explanation:

• Diamond is the hardest naturally occurring substance found on Earth. Diamonds are formed in the mantle. They brought to the earth’s crust due to volcanism. Most of the diamonds occur in dykes, sill etc. 

• Statement 1 is Incorrect and Statement 2 is Correct: Igneous rocks form out of magma and lava from the interior of the earth, they are known as primary rocks. Igneous rocks are classified based on texture. The texture depends upon the size and arrangement of grains or other physical conditions of the materials.
• Statement 3 is Correct: Metamorphism is a process by which recrystallisation and reorganisation of minerals occur within a rock. This occurs due to pressure, volume and temperature changes. When rocks are forced down to lower levels by tectonic processes or when molten magma rising through the crust comes in contact with the crustal rocks, metamorphosis occurs. In the process of metamorphism in some rocks grains or minerals get arranged in layers or lines. Such an arrangement is called foliation or lineation.

• Option B is the Correct Answer: Silica and Aluminium are two main constituents of Graphite.

• Option C is the Correct Answer: Stalactite and stalagmite, elongated forms of various minerals deposited from solution by slowly dripping water. A stalactite hangs like an icicle from the ceiling or sides of a cavern. A stalagmite appears like an inverted stalactite, rising from the floor of a cavern.