1.
What type of weathering causes disintegration of rocks without chemical change?
Correct Answer
B. pHysical weathering
Explanation
Physical weathering causes the disintegration of rocks without chemical change. This process occurs when rocks are broken down into smaller pieces through physical forces such as temperature changes, pressure, and mechanical actions like frost wedging, abrasion, and root growth. Unlike chemical weathering, physical weathering does not involve any alteration in the chemical composition of the rocks. Instead, it only breaks them apart into smaller fragments, which can be further weathered by other processes.
2.
What type of weathering is also known as mechanical weathering?
Correct Answer
A. pHysical weathering
Explanation
Physical weathering, also known as mechanical weathering, refers to the breakdown of rocks into smaller pieces without changing their chemical composition. It is caused by physical forces such as temperature changes, freeze-thaw cycles, and abrasion. These forces weaken the rocks and cause them to crack, break, or disintegrate into smaller fragments. Some common examples of physical weathering include the freeze-thaw action of water in cracks, wind erosion, and the impact of waves on coastal rocks.
3.
What type of weathering is also known as thermal stress weathering?
Correct Answer
C. Isolation weathering
4.
Which of these is not an agent of denudation?
Correct Answer
D. Weather
Explanation
Weather is not an agent of denudation because it refers to the conditions of the atmosphere, such as temperature, precipitation, and humidity. While weather can indirectly contribute to denudation processes by influencing other agents like wind and water, it is not a direct agent itself. Denudation refers to the wearing away and removal of the Earth's surface materials, which is primarily caused by agents like ice, waves, and wind through processes like erosion and weathering.
5.
What is the primary process in physical weathering?
Correct Answer
D. Abrasion
Explanation
Abrasion is the primary process in physical weathering. This process involves the wearing down and breaking apart of rocks and minerals through the mechanical action of friction, caused by the movement of water, wind, ice, or other forces. It occurs when particles or debris continuously rub against the surface of rocks, causing them to chip, crack, and eventually disintegrate. Abrasion is a common process in areas with high wind or water flow, such as deserts or riverbeds, where the constant movement of particles can erode and shape the landscape over time.
6.
Which of these does not cause physical weathering?
Correct Answer
C. Man
Explanation
Man does not cause physical weathering because physical weathering refers to the breakdown of rocks and minerals through natural processes such as temperature changes, frost action, and pressure. While human activities can contribute to weathering through processes like chemical weathering or erosion, they are not considered as causes of physical weathering. Therefore, man is the correct answer as it does not directly cause physical weathering.
7.
Which of these is not a process of chemical weathering?
Correct Answer
D. Abrasion
Explanation
Abrasion is not a process of chemical weathering because it involves the physical wearing down of rocks and minerals through friction and impact, rather than chemical reactions. Chemical weathering processes, on the other hand, involve the alteration of rock and mineral composition through chemical reactions. Dissolution, carbonation, and oxidation are all examples of chemical weathering processes, where minerals are dissolved, carbon dioxide reacts with water to form carbonic acid, and minerals react with oxygen respectively.
8.
Which of these increase chemical weathering rates in rocks?
Correct Answer
C. Lichens
Explanation
Lichens increase chemical weathering rates in rocks. Lichens are a symbiotic relationship between fungi and algae or cyanobacteria. They produce organic acids that can dissolve minerals in rocks, leading to their weathering. This process is known as biological weathering. Algae, ants, and fungi do not have the same effect on chemical weathering rates as lichens do.
9.
What type of rock is obtained from pre-existing rocks?
Correct Answer
C. MetamorpHic rocks
Explanation
Metamorphic rocks are formed from pre-existing rocks that have undergone intense heat and pressure, causing the minerals and textures to change. This process occurs deep within the Earth's crust and can be influenced by tectonic activity or contact with magma. Sedimentary rocks are formed from the accumulation and hardening of sediments, while igneous rocks are formed from the solidification of molten material. Fold rocks do not exist as a distinct rock type and are likely a misinterpretation or incomplete option. Therefore, the correct answer is metamorphic rocks.
10.
What is the average pH of rainfall in an unpolluted environment?
Correct Answer
B. 5.6
Explanation
The average pH of rainfall in an unpolluted environment is 5.6. pH is a measure of the acidity or alkalinity of a substance, with values below 7 indicating acidity and values above 7 indicating alkalinity. A pH of 5.6 suggests that the rainfall is slightly acidic, which is normal for unpolluted environments.