Here are 30 short questions and answers (2-3 marks each) based on the chapter "Our Earth: Changing" from CBSE Geography:

1. What is the lithosphere?

The lithosphere is the solid outer layer of the Earth, consisting of the crust and the upper part of the mantle. It includes landforms like mountains, plateaus, and plains.

2. What causes earthquakes?

Earthquakes are caused by sudden movements of tectonic plates due to seismic activity along faults, volcanic eruptions, or human activities like mining and reservoir-induced seismicity.

3. Name the three layers of the Earth.

The three layers of the Earth are:

1. Crust (outermost layer)

2. Mantle (middle layer)

3. Core (innermost layer, divided into the outer and inner core)

4. What are endogenic forces?

Endogenic forces are internal forces that originate inside the Earth and cause changes like earthquakes, volcanic eruptions, and mountain formation.

5. What are exogenic forces?

Exogenic forces are external forces acting on the Earth's surface, such as weathering, erosion, and deposition caused by wind, water, and ice.

6. What are tectonic plates?

Tectonic plates are large, rigid slabs of the Earth's lithosphere that float on the semi-molten mantle. Their movement causes earthquakes, volcanoes, and the formation of mountains.

7. What is a volcano?

A volcano is an opening in the Earth's crust through which lava, ash, and gases erupt due to magma rising from beneath the surface.

8. What are the types of volcanoes?

Volcanoes are classified into:

1. Active volcanoes (erupt frequently, e.g., Mount Etna)

2. Dormant volcanoes (inactive but may erupt in the future, e.g., Mount Vesuvius)

3. Extinct volcanoes (no longer erupt, e.g., Mount Kilimanjaro)

9. What are seismic waves?

Seismic waves are energy waves generated by an earthquake that travel through the Earth’s layers, causing vibrations and destruction.

10. What is weathering?

Weathering is the breaking down of rocks on the Earth’s surface due to natural factors like temperature changes, water, and biological activity.

11. How does a tsunami occur?

A tsunami occurs due to underwater earthquakes, volcanic eruptions, or landslides, causing large sea waves that can flood coastal areas.

12. What is erosion?

Erosion is the wearing away of the Earth's surface by natural agents like water, wind, glaciers, and waves.

13. Name the main agents of erosion.

The main agents of erosion are rivers, wind, glaciers, and sea waves.

14. What is deposition?

Deposition is the process by which eroded materials like sand, silt, and rocks are dropped or settled in a new location by water, wind, or ice.

15. How do rivers shape the land?

Rivers erode land, transport sediments, and deposit materials, forming landforms like waterfalls, valleys, meanders, and deltas.

16. What are the types of earthquake waves?

There are three types of earthquake waves:

1. Primary (P-waves) – travel fastest through solids and liquids.

2. Secondary (S-waves) – travel only through solids.

3. Surface waves – cause the most damage on the Earth's surface.

17. What is a delta?

A delta is a triangular landform at the mouth of a river, formed by the deposition of sediments as the river slows down before entering a sea or ocean.

18. What is a landslide?

A landslide is the sudden movement of rock and soil down a slope due to gravity, earthquakes, or heavy rainfall.

19. How does wind cause erosion?

Wind erodes land by blowing away loose particles, forming landforms like sand dunes and mushroom rocks in deserts.

20. What is a glacier?

A glacier is a large mass of ice that moves slowly over land, shaping valleys and depositing debris.

21. What are the effects of an earthquake?

Earthquakes cause building collapses, tsunamis, landslides, loss of life, and infrastructure damage.

22. What is a fault?

A fault is a crack in the Earth's crust along which movement occurs during an earthquake.

23. How do humans contribute to erosion?

Humans contribute to erosion through deforestation, overgrazing, mining, and construction activities.

24. What is the difference between a focus and an epicenter?

Focus: The point inside the Earth where an earthquake originates.

Epicenter: The point on the Earth's surface directly above the focus.

25. What is a seismograph?

A seismograph is an instrument that records the intensity and duration of earthquakes by measuring seismic waves.

26. What are the three types of mountains?

1. Fold mountains (Himalayas)

2. Block mountains (Vosges Mountains)

3. Volcanic mountains (Mount Fuji)

27. What are sea waves?

Sea waves are rhythmic movements of seawater caused by wind, earthquakes, or gravitational forces.

28. How do glaciers shape the land?

Glaciers erode and transport rocks, creating landforms like U-shaped valleys, moraines, and fjords.

29. What is an earthquake hazard map?

An earthquake hazard map shows areas prone to earthquakes based on seismic activity and past occurrences.

30. How can we reduce the impact of earthquakes?

We can reduce earthquake impacts by:

Constructing earthquake-resistant buildings

Creating early warning systems

Conducting disaster preparedness drills