Geomorphology

To solve this problem, we need to correctly match the processes listed in Group I with the geomorphic features in Group II based on geological knowledge.

1. Dissolution (P): Dissolution is a process of chemical weathering where soluble minerals in rocks, like limestone, are dissolved by acidic water, often leading to the formation of sinkholes. Therefore, we match P-3.
2. Abrasion (Q): Abrasion is a physical weathering process caused by friction and impact of particles carried by wind or water, often leading to the formation of unique erosional features such as mushroom rocks. Thus, we pair Q-1.
3. Deposition (R): This is a geological process where sediments are laid down primarily by wind, water, and ice. It results in the formation of accumulative structures such as moraines, which are ridges of debris deposited by glaciers. Hence, we associate R-4.
4. Onion skin weathering (S): Also known as exfoliation, this process involves layers pealing from rocks due to thermal expansion and contraction. This leads to the formation of exfoliation domes. Therefore, S corresponds to 2, or S-2.

By systematically matching each process with its corresponding geomorphic feature, we determine that the correct answer is:

P-3, Q-1, R-4, S-2

To solve the problem, we need to match each geomorphic feature in Group I with the corresponding process in Group II. Let's evaluate each pairing:

1. Cirque (P) - A cirque is a bowl-shaped, amphitheater-like depression eroded into mountainsides and valley heads, formed by glacial activity. Hence, the correct match is with 2 , Glacial.
2. Ventifact (Q) - Ventifacts are rocks that have been shaped, faceted, and polished by wind-driven sand, indicating Aeolian processes. Therefore, the correct match is with 4 , Aeolian.
3. Point bar (R) - A point bar is a sediment deposit found on the inside bends of streams and rivers, formed by the process of sedimentation in a fluvial (river) system. Hence, it matches with 1 , Fluvial.
4. Tephra (S) - Tephra refers to the fragments of volcanic rock and lava that are blasted into the air during volcanic eruptions. Thus, it is linked with 3 , Volcanic.

Based on these evaluations, the correct option is P-2, Q-4, R-1, S-3.

The question asks us about the factors on which the acceleration due to gravity on Earth's surface depends. Let's understand each factor:

1. Latitude: The acceleration due to gravity varies with latitude due to the Earth's rotation and its oblate spheroid shape. It is generally higher at the poles and lower at the equator. This is because the centrifugal force due to Earth's rotation is maximum at the equator, counteracting gravitational pull slightly, and minimum at the poles.
2. Longitude: The position of longitude does not affect the acceleration due to gravity significantly. Gravity varies with latitude but not with longitude, so this option is incorrect.
3. Elevation: The acceleration due to gravity decreases with an increase in altitude (elevation). This is because the gravitational force decreases with distance from the Earth's center, following the inverse-square law.
4. Topography of the surrounding terrain: Local variations in topography, such as mountains, valleys, and density differences in Earth's crust, can cause slight variations in gravity. This means that gravity is indeed influenced by local geographical formations.

Thus, the correct options are:

• latitude
• elevation
• topography of the surrounding terrain

These factors contribute to variations in gravitational strength at different places on Earth's surface. Understanding these variations is essential in geodesy and related geological studies.

The question asks which factor causes sediment movement parallel to the shoreline in a coastal area. Let's analyze the given options:

1. Longshore current: This is a water current that moves parallel to the shore. It is created by waves that approach the shore at an angle, causing sediments to be transported along the coast. This is known as longshore drift, and it effectively moves sediments parallel to the shoreline, reshaping the coast over time.
2. Rip current: Unlike longshore currents, rip currents move perpendicularly from the shore, pulling water and sediments away from the coast into deeper water. They do not facilitate sediment movement parallel to the shoreline.
3. Backwash: This is the water that flows back into the sea after a wave has broken on the shore. It generally moves sediments perpendicular to the shoreline, either inward or outward, not parallel.
4. Edge wave: These are stationary waves that run along the coast and are perpendicular to the incoming waves. They have a limited role in sediment transport parallel to the shore.

Based on the above analysis, the correct answer is Longshore current, as it is responsible for transporting sediments parallel to the shoreline through the mechanism known as longshore drift.

The question asks us to identify a volcanic landform characterized by a gentle slope of less than 10 degrees and formed from basaltic lava eruption. Let's evaluate each option to determine the correct answer:

1. Shield volcano: These are large, broad volcanoes with gentle slopes due to low-viscosity basaltic lava that can travel long distances. Typically, the slopes of shield volcanoes are less than 10 degrees, making them fit the description perfectly. Hence, this is the correct option.
2. Composite volcano: Also known as stratovolcanoes, these have steeper profiles and are formed from a combination of explosive eruptions and lava flows, usually involving andesitic or dacitic lava. The slopes are much steeper than 10 degrees, ruling out this option.
3. Lava dome: These occur when viscous lava piles up near the vent, creating a dome-shaped, steep-sided mound. Lava domes have steep slopes, certainly steeper than 10 degrees, eliminating this as a possible answer.
4. Caldera: A caldera forms after the collapse of a volcano's summit following a major eruption, leading to a large crater. They are not characterized by gradual slopes formed by lava flow, so this does not match the question’s description.

Based on the above analysis, the correct choice is the Shield volcano. This type of volcano has the gentle slopes described in the question and is the result of the eruption of low-viscosity basaltic lava.

Conclusion: The gently sloping volcanic landform resulting from basaltic lava is the Shield volcano.

To solve this question, we need to match the geomorphic agents from Column I with their corresponding landforms in Column II. Let's analyze each geomorphic agent and its characteristic landform:

1. Wind: Wind is a major agent of erosion and deposition in desert areas. One of the significant landforms created by wind action is the Yardang. Yardangs are streamlined protuberances carved from bedrock or any other consolidated or semi-consolidated material by the dual action of wind abrasion by dust and sand. Hence, P (Wind) matches with 2 (Yardang).
2. Groundwater: Groundwater erosion, especially in limestone regions, creates specific landforms such as Doline. Dolines are small to medium-sized closed depressions that can form naturally by dissolution of limestone, typically in karst landscapes. Thus, Q (Groundwater) matches with 3 (Doline).
3. Glacier: Glaciers sculpt many unique landforms, one of which is the Drumlin. Drumlins are elongated hills formed by the streamlined movement of glacial ice sheets across rock debris, or till. So, R (Glacier) matches with 4 (Drumlin).
4. River: Rivers create various depositional and erosional features. A common depositional feature in a river floodplain is a Backswamp. Backswamps are marshy or swampy areas found when rivers deposit sediments in their floodplains. Hence, S (River) matches with 1 (Backswamp).

By matching each geomorphic agent with its corresponding landform, we conclude that the correct answer is P – 2, Q – 3, R – 4, S – 1.

The question asks which of the given processes is NOT a mechanism for bedload sediment transport in a river channel. To solve this, we need to understand the different mechanisms of sediment transport:

1. Sliding: This occurs when particles move down a slope in contact with the riverbed. It is a common mechanism for bedload transport, where various environmental factors cause particles to slide along the bed.
2. Rolling: This mechanism involves particles rolling along the riverbed. Rolling is typical for larger sediment particles that are too heavy to be lifted easily.
3. Saltation: This refers to particles being lifted intermittently into the flow and then falling back to hit the bed, causing them to hop or bounce downstream. This is a common process in bedload transport.
4. Cavitation: This is a process that occurs due to the formation and collapse of vapor bubbles in a liquid. Cavitation is not related to the physical transport of sediments along a riverbed. It is more relevant to hydraulic machines and fluid flow in pipes and doesn't contribute to sediment movement in a river channel.

Given these explanations, we can conclude that Cavitation is NOT a mechanism for bedload sediment transport. It is unrelated to sediment movement and pertains more to fluid mechanics involving vapor bubble formation. Therefore, the correct answer is:

Cavitation

To understand which types of sand dunes are formed primarily by uni-directional winds, we need to examine the characteristics of different dunes:

1. Linear Dunes:

   These dunes are typically straight or slightly sinuous sand ridges that can extend for great lengths. They form under bidirectional wind regimes, where the wind comes from two distinct directions. Hence, linear dunes are not mainly formed by uni-directional winds.

2. Parabolic Dunes:

   Parabolic dunes have a U-shape with the open end facing away from the wind direction. These dunes typically form in areas where vegetation is present, stabilizing some parts of the dune. They are associated with uni-directional winds, where the consistent wind direction pushes the sand into the parabolic shape. Therefore, parabolic dunes form primarily by uni-directional winds.

3. Barchan Dunes:

   Barchan dunes are crescent-shaped with the tips or "horns" pointing downwind. These dunes form in flat, arid regions with a limited supply of sand, and they are shaped by steady, strong uni-directional winds. The convex side of the dune faces the wind, which continuously moves sand over the dune crest. Thus, barchan dunes are also formed mainly by uni-directional winds.

Based on the above analysis, the dunes that form primarily by uni-directional winds are Parabolic dunes and Barchan dunes. These types are correctly identified in the options provided.