Physics 2024 Paper II 20 marks Discuss
Q7
(a) Discuss the distribution and characteristics of the black soil in India. 10 (b) Examine the role of rivers in the economic development of India. 10
Directive word: Discuss
This question asks you to discuss. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.
See our UPSC directive words guide for a full breakdown of how to respond to each command word.
How this answer will be evaluated
Approach
The directive 'discuss' for part (a) requires a balanced treatment of distribution and characteristics, while 'examine' for part (b) demands critical analysis of rivers' multifaceted economic roles. Allocate approximately 45% of content to part (a) covering the Deccan Traps region, Maharashtra-Gujarat-Madhya Pradesh belt, and soil properties like high clay content, moisture retention, and self-ploughing nature; 55% to part (b) addressing irrigation, hydropower, inland navigation, industrial clustering, and river-linking debates. Structure with regional maps for soil distribution, a comparative table of major river systems' economic contributions, and conclude with challenges like soil degradation and inter-state water disputes.
Key points expected
- Part (a): Distribution across Deccan Traps (Maharashtra, Gujarat, Madhya Pradesh, Karnataka, Telangana, Andhra Pradesh) with percentage coverage and geological origin from basaltic lava weathering
- Part (a): Key characteristics—high clay content (montmorillonite), deep cracks in summer (self-ploughing), poor organic content, moisture retention, suitability for cotton (black cotton soil), wheat, jowar, and limitations like waterlogging
- Part (b): Irrigation role—Ganga system (Uttar Pradesh, Bihar, West Bengal agriculture), Godavari-Krishna delta cultivation, groundwater recharge contribution; statistics on canal-irrigated area
- Part (b): Hydropower and navigation—Bhakra-Nangal, Hirakud, Tehri dams; National Waterways 1 (Ganga), NW-2 (Brahmaputra), NW-3 (Kerala backwaters) for freight movement
- Part (b): Industrial and urban dimensions—riverfront development (Ahmedabad, Varanasi), thermal power plant cooling, inter-linking projects (Ken-Betwa, Polavaram) with critical assessment of ecological and displacement costs
Evaluation rubric
| Dimension | Weight | Max marks | Excellent | Average | Poor |
|---|---|---|---|---|---|
| Concept correctness | 25% | 5 | Accurately identifies regur soil formation from Deccan Trap basalt weathering, correct classification of black soil types (deep/shallow), precise naming of river basins and their specific economic contributions (e.g., Hirakud on Mahanadi for Sambalpur industry, Ganga for 47% of India's irrigated area) | Basic correct identification of black soil regions and general river economic roles but with minor errors in extent or conflation of soil types; vague statements like 'rivers help agriculture' without specificity | Fundamental errors such as confusing black soil with alluvial soil regions, attributing black soil to Himalayan origin, or claiming rivers are economically insignificant in peninsular India |
| Derivation rigour | 15% | 3 | Logical causal chains: basaltic lava → weathering → high iron-magnesium clay minerals → swelling-shrinking property → self-ploughing; river gradient → flow velocity → navigation suitability → port development (Haldia, Paradip) | Some logical connections present but gaps in explaining why black soil retains moisture or how river morphology affects economic use; descriptive rather than analytical linkages | No causal reasoning; lists facts without connecting formation to characteristics or river presence to economic outcomes; contradictory statements about soil behavior |
| Diagram / FBD | 20% | 4 | Clear India outline map showing black soil belt (hatched) covering 16% of area, major rivers labeled with economic zones; OR cross-section diagram of soil profile showing horizon development, depth, and crack patterns; OR river basin map with dams, canals, and industrial corridors marked | Rough sketch with correct general region but missing state boundaries or key rivers; OR table format substituting for diagram with columns for soil type/state/crops or river/state/economic use | No diagram or map; OR incorrect map showing black soil in Gangetic plains or northeast; OR irrelevant diagrams like tectonic plate boundaries |
| Numerical accuracy | 20% | 4 | Precise data: black soil covers ~5.46 lakh sq km (16.6% of India); Maharashtra has 50% of black soil; cotton occupies 8-9 million hectares; National Waterways carry 72 million tonnes freight (2022-23); hydropower potential ~148,700 MW; river-linked irrigation targets | Approximate figures with minor errors (e.g., black soil 'about 15%' without specificity, 'millions depend on Ganga' without quantification); rounded estimates acceptable but lacking authoritative sourcing | No numerical data; OR grossly inflated/deflated figures (black soil '70% of India', 'rivers provide 90% of power'); confused units (sq km vs hectares) |
| Physical interpretation | 20% | 4 | Integrates both parts: explains how black soil's moisture retention enables dryland farming in rain-deficient Deccan regions, reducing river irrigation dependency; contrasts with Ganga alluvium requiring intensive canal networks; critically evaluates river-linking as response to soil-climate mismatches; discusses climate change impacts on both soil moisture and river flow regimes | Separate treatment of both parts without synthesis; some interpretation of soil behavior or river economics individually but no cross-referencing; mentions challenges like salinity or flooding without integrated analysis | Purely factual regurgitation; no interpretation of why these geographical features matter for contemporary development; ignores current debates (soil health cards, inter-state water tribunals, pollution-economic tradeoffs) |
Practice this exact question
Write your answer, then get a detailed evaluation from our AI trained on UPSC's answer-writing standards. Free first evaluation — no signup needed to start.
Evaluate my answer →More from Physics 2024 Paper II
- Q1 Q1. (a) A particle limited to the x-axis has the wave function φ(x) = bx² between x = 0 and x = 2; the wave function φ(x) = 0 elsewhere. (i…
- Q2 Q2. (a) Prove that : (i) [L², Lz] = 0 (ii) [Lz, L+] = ℏL+ (iii) [L+, L-] = 2ℏLz (iv) L+ L- = L² - Lz² + ℏLz where ℏ = h/2π (ℏ is Planck's c…
- Q3 (a) How do Stokes lines appear in Raman spectrum as per classical and quantum theory of Raman effect ? 20 marks (b) What is Lamb shift in t…
- Q4 (a) (i) Using free electron theory of metals, calculate the Fermi energy level of sodium atom at absolute zero. Assume that sodium has one…
- Q5 (a) Compare nuclear density of hydrogen (₁H¹) with its atomic density. (Assume the atom to have the radius of its first Bohr orbit). What i…
- Q6 (a) Does the nucleus possess magnetic moment ? Justify your answer. Define nuclear magneton (μN) and Bohr magneton (μB). Calculate their va…
- Q7 (a) Discuss the distribution and characteristics of the black soil in India. 10 (b) Examine the role of rivers in the economic development…
- Q8 (a) Discuss the factors responsible for the uneven distribution of population in India. 10 (b) Analyse the impact of globalization on the I…