Consider the following:Pyroclastic debrisAsh and dustNitrogen compoundsSulphur compoundsHow many of

Q: What is UPSC Prelims?

UPSC Prelims is a competitive examination conducted in India. This question is from the 2024 UPSC Prelims Geography paper.

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This UPSC Prelims 2024 Geography question has a easy difficulty level.

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Question

Consider the following:Pyroclastic debrisAsh and dustNitrogen compoundsSulphur compoundsHow many of the above are products of volcanic eruptions?

Accepted Answer

Correct Answer: D — All fourStep-by-step Solution:A volcanic eruption releases a diverse range of materials from the Earth's interior onto or near the surface. These can be classified into lava (liquid rock), pyroclastic materials (fragmented solid materials), and gases (including compounds of various elements).Item 1 — Pyroclastic debris: This is a volcanic product. Pyroclastic materials (from Greek 'pyro' = fire, 'klastos' = broken) include all fragmented solid materials ejected during volcanic eruptions — volcanic bombs (large, aerodynamically shaped fragments), lapilli (pea- to walnut-sized fragments), scoria, pumice, and tephra. These are among the most destructive products of explosive volcanic eruptions (e.g., pyroclastic flows). ✓Item 2 — Ash and dust: This is a volcanic product. Volcanic ash consists of tiny glass shards and pulverised rock fragments (less than 2 mm diameter) that are blasted into the atmosphere during eruptions. Volcanic dust (particles Item 3 — Nitrogen compounds: This is a volcanic product. Volcanic gases include nitrogen compounds such as ammonia (NH₃) and minor amounts of nitrogen oxides. Nitrogen gas (N₂) is also present. These nitrogen compounds are released from magmatic degassing as magma rises and pressure decreases. ✓Item 4 — Sulphur compounds: This is a volcanic product. Sulphur compounds — primarily sulphur dioxide (SO₂) and hydrogen sulphide (H₂S) — are among the most significant volcanic gases. SO₂ reacts with water vapour in the atmosphere to form sulphuric acid droplets (aerosols), which are responsible for volcanic winter effects and acid rain. ✓All four items are products of volcanic eruptions.Why other options are incorrect:Options A, B, C: All undercount. Every item listed (pyroclastic debris, ash and dust, nitrogen compounds, sulphur compounds) is a genuine product of volcanic activity.Key Concept: Volcanic products classification: Lava: Molten rock that reaches the surface; types by viscosity — basaltic (fluid, low silica), andesitic, rhyolitic (viscous, high silica). Pyroclastic materials: Volcanic bombs (>64mm); Lapilli (2–64mm); Ash (

Consider the following:Pyroclastic debrisAsh and dustNitrogen compoundsSulphur compoundsHow many of the above are products of volcanic eruptions?

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Consider the following:Pyroclastic debrisAsh and dustNitrogen compoundsSulphur compoundsHow many of the above are products of volcanic eruptions?

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More Questions from Interior of the Earth – Layers, Plate Tectonics & Earthquakes

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