Paper II · Part B — Geography

Rocks and their Classification

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Core5 mapped NDA questions

Build the idea

Build exam-ready understanding by connecting the core idea, formulas or facts, worked example and previous NDA questions. Focus on why each rule works, then test it under timed conditions.

Concept

Rocks are natural aggregates of minerals, classified by how they form. The three families are igneous, sedimentary and metamorphic, linked by the rock cycle.

Each type has characteristic examples tested in the exam.

Key Points & Formulas

Igneous: formed from cooled magma/lava (e.g., granite, basalt) — 'primary rocks'.
Sedimentary: formed by deposition and compaction (e.g., sandstone, limestone); may contain fossils.
Metamorphic: formed by heat/pressure on existing rocks (e.g., marble from limestone, slate from shale).
The rock cycle continuously converts one type into another.

Worked Example

Q. Marble is formed from which rock and by what process?

Marble is a metamorphic rock.

It forms when limestone (a sedimentary rock) is subjected to heat and pressure.

Common traps

Reading the prompt too quickly and missing a qualifier.
Memorising the result without checking when it applies.
Skipping units, signs, chronology or the final reasonableness check.

NDA shortcuts

State the governing rule before substituting values.
Eliminate impossible options before doing full calculation.

One-screen revision sheet

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Core definition
Most-used rule
One representative example

Past-paper bank

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5 NDA questions

Choose an answer before the solution appears. Option order is mixed automatically.

Question 1

NDA I 2026

Quartzite is metamorphosed from which one of the following rocks?

Question 2

NDA II 2025

Which one among the following volcanic island chains is NOT associated with mid-oceanic ridge?

Question 3

NDA II 2024

Which one of the following is an example of both an igneous as well as a metamorphic rock ?

Question 4

NDA II 2024

The lowest part of most bolsons is occupied by a landform called playa. Which category of landform formation does it represent ?

Question 5

NDA I 2024

Which of the following statements regarding Barchan is/are correct?
1. It is a crescent shaped mound of sand, which is deposited by the wind blowing constantly from one direction in a desert.
2. The windward side has a convex steep slope with maximum height at the centre.
3. Two ends of Barchan are called horns and point opposite to the direction the wind blows.
Select the answer using the code given below:

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