1. Weathering (Breaking of Rocks)
Weathering is the process of breaking down rocks into smaller pieces without moving them.
It is caused by:
1. **Physical** – due to heat, cold, frost. 2. **Chemical** – reaction with air, water, acids. 3. **Biological** – plant roots, animals, human activity.
- Temperature changes
- Water, wind, ice
- Chemical reactions
- Plants & animals
1. **Physical** – due to heat, cold, frost. 2. **Chemical** – reaction with air, water, acids. 3. **Biological** – plant roots, animals, human activity.
हिंदी: Weathering = चट्टानों का टूटना, लेकिन स्थान परिवर्तन नहीं होता।
Break → हाँ, Move → नहीं।
2. Erosion (Removal of Weathered Material)
Erosion is the **removal or transportation** of weathered rock material by:
- Running water
- Wind
- Glaciers
- Sea waves
हिंदी: Erosion = टूटे हुए कणों को एक जगह से दूसरी जगह ले जाना (जैसे नदी बहा ले जाए)।
Break + Move → दोनों।
3. Deposition (Dropping of Material)
When eroded material is finally dropped or settled, it is called **deposition**.
Example: River depositing sand near its mouth → forming deltas.
4. Landforms Created by Running Water (River)
Upper Course (Mountains)
• V-shaped valleys
• Gorges
• Waterfalls
Middle Course • Meanders (snake-like curves) • Oxbow lakes
Lower Course • Floodplains • Levees • Deltas
Middle Course • Meanders (snake-like curves) • Oxbow lakes
Lower Course • Floodplains • Levees • Deltas
हिंदी:
Upper course = काटना (erosion)
Middle course = मोड़ बनाना
Lower course = जमा करना (deposition)
5. Landforms Created by Wind (Deserts)
- Sand dunes
- Barchans
- Yardangs
- Mushroom rocks
6. Landforms Created by Glaciers (Snow/Ice)
- U-shaped valleys
- Hanging valleys
- Moraines
- Cirques
हिंदी Shortcut:
River valley = V-shape
Glacier valley = U-shape
7. Landforms Created by Sea Waves
- Sea cliffs
- Sea caves
- Sea arches
- Stacks
8. Difference Between Weathering & Erosion
Weathering: Rocks break down but stay in place.
Erosion: Rocks break + move away by water, wind, ice.
हिंदी Summary:
Weathering = टूटना
Erosion = टूटना + बहना / उड़ना / खिसकना
📘 Practice Questions (NDA Style)
1. Weathering means:
a) Movement of rocks b) Breaking of rocks in place c) Formation of deltas d) Melting of ice
2. A U-shaped valley is formed by:
a) Wind b) River c) Glacier d) Sea waves
3. An oxbow lake is formed by:
a) Wind erosion b) River meandering c) Sea waves d) Glacier deposition
4. Sand dunes are features created by:
a) Rivers b) Glaciers c) Wind d) Sea waves
5. Deltas are formed due to:
a) River deposition b) Erosion by ice c) Chemical weathering d) Tidal action
a) Movement of rocks b) Breaking of rocks in place c) Formation of deltas d) Melting of ice
2. A U-shaped valley is formed by:
a) Wind b) River c) Glacier d) Sea waves
3. An oxbow lake is formed by:
a) Wind erosion b) River meandering c) Sea waves d) Glacier deposition
4. Sand dunes are features created by:
a) Rivers b) Glaciers c) Wind d) Sea waves
5. Deltas are formed due to:
a) River deposition b) Erosion by ice c) Chemical weathering d) Tidal action
Answers:
1 – b) Breaking of rocks in place
2 – c) Glacier
3 – b) River meandering
4 – c) Wind
5 – a) River deposition
1 – b) Breaking of rocks in place
2 – c) Glacier
3 – b) River meandering
4 – c) Wind
5 – a) River deposition
Quick Recap | सार
Now you should be able to:
- Recall the most important ideas of this topic.
- Solve typical NDA-style questions from this chapter.
- Spot and avoid common traps used in competitive exams.
Self-check: 3–4 random questions उठा कर देखिए – अगर आसानी से हो रहे हैं, तो chapter strong है।
Common Exam Mistakes | आम गलतियाँ
- Concept ठीक से clear न करना और सीधे रटने की कोशिश करना।
- Question पूरी तरह पढ़े बिना answer mark कर देना।
- Figures, dates, या formulas को last step में verify न करना।
NDA में smart strategy यह है कि आसान वाले सवाल पहले, doubtful बाद में – और silly mistakes से बचना सबसे ज़रूरी है।