With reference to stresses in earth materials, consider the following statements: 1. Molecular stresses are unaffected by temperature changes. 2. Shear stresses are separating forces acting along the faces of earth materials. 3. Gravitational stress is the only stress that breaks rocks. Which of the statements given above is/are correct?

The correct option is 2 only Explanation Geomorphic processes are driven by forces that create stress within earth materials. These stresses lead to deformation, fracturing, and movement of rock masses. Understanding the nature of these stresses is essential to analyzing weathering and mass movements. Statement-wise Analysis: - Statement 1 is Incorrect: Shear stresses are forces that act tangentially or parallel to the surfaces of earth materials. In the context of geomorphic processes, they are described as separating forces because they break the continuity of the material by causing slippage or fracture along specific planes. - Statement 2 is Correct: Molecular stresses are directly influenced by factors such as temperature changes, crystallization, and melting. For instance, thermal expansion and contraction due to temperature fluctuations generate significant molecular stress within rocks, leading to disintegration. - Statement 3 is Incorrect: While gravitational stress (force of gravity per unit area) is a fundamental force affecting earth materials, it is not the only stress that breaks rocks. Rocks are also broken by molecular stresses (thermal expansion), chemical stresses (crystal growth), and tectonic stresses. Key Takeaway: Shear stress acts along the faces of materials to separate them, while molecular stress is induced by internal changes such as temperature fluctuations and crystallization.

With reference to stresses in earth… - NCERT Class 11 Geography MCQ

NCERT Class 11 Geography — Chapter 4: Geomorphic Processes

mcqhard

With reference to stresses in earth materials, consider the following statements:

Molecular stresses are unaffected by temperature changes.
Shear stresses are separating forces acting along the faces of earth materials.
Gravitational stress is the only stress that breaks rocks.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Fundamentals of Physical Geography · Page 39

Options

A2 only
B1, 2 and 3
C1 only
D1 and 3 only

Did you get this right?

Solution

The correct option is

2 only

Explanation

Geomorphic processes are driven by forces that create stress within earth materials. These stresses lead to deformation, fracturing, and movement of rock masses. Understanding the nature of these stresses is essential to analyzing weathering and mass movements.

Statement-wise Analysis:

Statement 1 is Incorrect: Shear stresses are forces that act tangentially or parallel to the surfaces of earth materials. In the context of geomorphic processes, they are described as separating forces because they break the continuity of the material by causing slippage or fracture along specific planes.
Statement 2 is Correct: Molecular stresses are directly influenced by factors such as temperature changes, crystallization, and melting. For instance, thermal expansion and contraction due to temperature fluctuations generate significant molecular stress within rocks, leading to disintegration.
Statement 3 is Incorrect: While gravitational stress (force of gravity per unit area) is a fundamental force affecting earth materials, it is not the only stress that breaks rocks. Rocks are also broken by molecular stresses (thermal expansion), chemical stresses (crystal growth), and tectonic stresses.

Key Takeaway:
Shear stress acts along the faces of materials to separate them, while molecular stress is induced by internal changes such as temperature fluctuations and crystallization.

Your note

More from Chapter 4: Geomorphic Processes

Which chemical weathering process entails the absorption of water by minerals, leading to expansion?

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In geomorphology, the force applied per unit area on earth materials is termed:

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With reference to the factor of 'Time' in soil formation, consider the following statements: 1. It determines the maturation of soils and profile development. 2. Soils developing from recently deposited alluvium are considered mature. 3. No specific length of time can be fixed for soils to develop and mature. Which of the statements given above is/are correct?

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