Geography UGC NET UPSC 1

Assertion (A) : The ocean floors are much younger than continents.

Reason (R) : Owing to their low density and consequent buoyancy, the ocean floors are not forced down into the mantle in subduction zone.

Codes :

(A) Both (A) and (R) are true and (R) is the correct explanation of (A)

(B) Both (A) and (R) are true and (R) is not a correct explanation of (A)

(D) (A) is false, but (R) is true

The correct answer is (B) Both (A) and (R) are true and (R) is not a correct explanation of (A).

Explanation:

Assertion (A) states that the ocean floors are much younger than continents, which is true. This is due to a process called seafloor spreading, where new oceanic crust is formed at mid-ocean ridges through volcanic activity. As the new crust forms, it pushes older crust away, resulting in a continuous creation and movement of oceanic crust. Therefore, the ocean floors tend to be relatively young compared to continents.

Reason (R) states that the ocean floors are not forced down into the mantle in subduction zones due to their low density and buoyancy. While it is true that oceanic crust is denser than the underlying mantle, it is not the primary reason why ocean floors are younger than continents. The primary reason, as mentioned earlier, is seafloor spreading, not the lack of subduction. In reality, subduction does occur in certain regions where oceanic crust converges with continental crust, leading to the recycling of older oceanic crust into the mantle.

Hence, while both statements (A) and (R) are true, (R) does not provide an accurate explanation for why ocean floors are younger than continents, making option (B) the correct choice.

Comments

Regional Geography, Systematic Geography, Idiographic, Nomothetic, Inductive and Deductive Approaches

T wo major ways of studying Geography : the Regional Approach and the Systematic Approach . It also explains the related ideas of idiographic vs. nomothetic and inductive vs. deductive reasoning , especially in the context of the Hartshorne–Schaefer debate . 1. Regional Geography: “All About One” Regional Geography studies one particular region in detail . A region is an area that has some degree of homogeneity (sameness) within its boundary but is also unique or different from other regions . For example, if we study Palakkad District , we may study: Relief and drainage Climate Soil Vegetation Agriculture Population Occupation Economy Culture Political characteristics The purpose is to understand the complete geographical personality of Palakkad and the relationships among its different features. Key concepts Region: A geographical area with identifiable characteristics and boundaries. Homogeneity: Si...

Kuhn’s Paradigms

The given content explains Thomas S. Kuhn’s model of scientific development , its application to geography, and criticisms by Karl Popper, Paul Feyerabend, Michel Foucault , and others. 1. Basic Idea Kuhn argued that science does not develop continuously in a straight line . Instead, scientific development occurs through: Preparadigm → Paradigm → Normal Science → Crisis → Scientific Revolution → New Paradigm A new paradigm may replace an older one, producing a major change in the way scientists understand and study a subject. Concepts and Terminologies Concept / Term Simple Meaning Paradigm A commonly accepted framework/model that guides scientific research Exemplar A successful concrete problem-solution used as a model for future research Disciplinary Matrix Shared beliefs, values, concepts, methods and techniques of a scientific community Preparadig...

Models and Theories in Geography

Geographical Models A model is a simplified representation of reality used to describe, explain, simulate, and predict geographical phenomena. Types Physical (Iconic) Models – Three-dimensional representations (e.g., globe, relief model). Conceptual Models – Diagrams or frameworks explaining geographical relationships. Mathematical (Quantitative) Models – Equations and statistical models for spatial analysis and prediction. Simulation Models – Computer-based models that simulate geographical processes (e.g., climate, flood, urban growth). Major Geographical Models Model Scholar Year Concept Johann Heinrich von Thünen Agricultural Land Use Model 1826 Land use varies with distance from the market. Walter Christaller Central Place Model 1933 Distribution of settlements and services. Ernest Burgess Concentric Zone M...

Multispectral and Hyperspectral Imaging Systems

The main idea is how a remote-sensing sensor collects information about an area . A sensor does not simply take an ordinary photograph. It measures the electromagnetic energy reflected or emitted by objects in different wavelength bands . Depending on how many bands are measured and how the sensor collects them, different imaging systems are used. 1. Multispectral vs. Hyperspectral Multispectral imaging (MSI) records information in a limited number of relatively broad, separate spectral bands , such as blue, green, red, near-infrared and shortwave infrared. Hyperspectral imaging (HSI) records information in many narrow and usually contiguous spectral bands . Therefore, it provides a much more detailed spectral signature of each pixel. The resulting dataset is commonly called a hyperspectral data cube (hypercube) because it contains: X-axis → spatial information Y-axis → spatial information Z-axis → wavelength/spectral information Thus, hype...

Kuhn’s model in Geography

Thomas Kuhn (1922–1996) Thomas Samuel Kuhn was an American philosopher and historian of science . In 1962 , he published The Structure of Scientific Revolutions , introducing the concepts of paradigm and paradigm shift , which transformed the understanding of scientific progress. Definition: A framework of assumptions, concepts, and values that guide a group or field. Example (Science): Moving from a-earth-centered universe to a sun-centered solar system is a change in the scientific paradigm. Example (Daily Life): A shared cultural belief or a standard way of doing business. Kuhn's Model (1962) Kuhn's Model explains that science develops through successive paradigms rather than by continuous, gradual progress. Stages of Kuhn's Model Pre-paradigm Stage – No common theory; different ideas exist. Normal Science – Scientists work within an accepted paradigm . Crisis – Anom...

Vineesh V, Geography

Search This Blog