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NCERT Solutions For Class 11 Geography Chapter 3 Interior of the Earth - 2025-26

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Stepwise NCERT Answers for Interior of the Earth Class 11 (With Diagrams)

Explore the NCERT Solutions for Class 11 Geography Chapter Chapter-3: Interior of the Earth NCERT Solutions and get a clear understanding of Earth's structure. Stepwise answers and simple explanations help you master each concept for CBSE success.


This page covers exercise-wise solutions, accurate diagrams, and concise definitions so you can revise confidently. Free PDF download and marking-scheme guidance make your preparation smooth and effective.


Use these stepwise answers and exercise-wise solutions to avoid common mistakes, structure long answers well, and boost your chances of scoring full marks in the 2025–26 CBSE Geography exams.


Stepwise NCERT Answers for Interior of the Earth Class 11 (With Diagrams)

1. Multiple choice questions.


1. Which one of the following earthquake waves is more destructive?


  • (a) P-waves
  • (b) S-waves
  • (c) Surface waves
  • (d) None of the above

Answer: (c) Surface waves.


2. Which one of the following is a direct source of information about the interior of the earth?


  • (a) Earthquake waves
  • (b) Volcanoes
  • (c) Gravitational force
  • (d) Earth magnetism

Answer: (b) Volcanoes.


3. Which type of volcanic eruptions have caused Deccan Trap formations?


  • (a) Shield
  • (b) Flood
  • (c) Composite
  • (d) Caldera

Answer: (b) Flood.


4. Which one of the following describes the lithosphere:


  • (a) Upper and lower mantle
  • (b) Crust and upper mantle
  • (c) Crust and core
  • (d) Mantle and core

Answer: (b) Crust and upper mantle.


2. Answer the following questions in about 30 words.


1. What are body waves?


Answer: Body waves are earthquake waves that are generated at the earthquake focus and travel through the interior (body) of the earth. They consist of Primary (P) and Secondary (S) waves, which move in all directions from the point of origin.


2. Name the direct sources of information about the interior of the earth.


Answer: The direct sources of information about the interior of the earth are surface rocks, rocks obtained from mining, boreholes and deep drilling projects, and materials brought to the surface by volcanic eruptions (such as magma).


3. Why do earthquake waves develop shadow zone?


Answer: Earthquake waves develop a shadow zone because S-waves cannot travel through liquids and are stopped by the earth’s outer core, while P-waves are refracted. This results in certain regions not recording these waves, creating shadow zones.


4. Briefly explain the indirect sources of information of the interior of the earth other than those of seismic activity.


Answer: Indirect sources include increasing temperature and pressure with depth observed in mines, analysis of meteorites, the distribution of gravity (gravity anomalies), and magnetic surveys. These sources help scientists infer characteristics about the earth’s interior.


3. Answer the following questions in about 150 words.


1. What are the effects of propagation of earthquake waves on the rock mass through which they travel?


Answer: When earthquake waves propagate through rocks, they cause various effects depending on the nature of the waves and the rock types.

P-waves, or primary waves, compress and expand the rock, creating changes in density without causing significant structural damage. S-waves, or secondary waves, move the rocks perpendicular to the direction of wave propagation, creating troughs and crests which can cause more movement and potentially lead to cracking or displacement.

Surface waves, generated when body waves reach the surface, are the most destructive, causing major ground shaking, displacement of land, landslides, mudslides, liquefaction, avalanches, and even the collapse of natural and man-made structures. They may also lead to ground settlement and lurching. These effects can change the landscape and have devastating impacts on human settlements.


2. What do you understand by intrusive forms? Briefly describe various intrusive forms.


Answer: Intrusive forms are igneous rock bodies that develop when magma cools and solidifies within the earth’s crust, instead of erupting on the surface. These features vary in size and shape.

  1. Batholiths: Huge, deep-seated, granitic domes formed after denudation.

  2. Lacoliths: Dome-shaped with flat bases, connected by pipe-like conduits.

  3. Lapoliths: Saucer-shaped intrusive bodies.

  4. Phacoliths: Wavy masses found at the bases of synclines or tops of anticlines in folded rocks.

  5. Sills or Sheets: Thin, nearly horizontal magma bodies intruded between layers.

  6. Dykes: Vertical, wall-like bodies formed when magma solidifies in cracks, often acting as feeders for volcanic eruptions.

Each form results from the movement and solidification of magma within the crust, shaping the subsurface landscape.


Mastering the Interior of the Earth: Key Concepts for Exam Success

Understanding the structure of the earth and the nature of earthquakes is crucial for Geography. Explore the importance of NCERT Solutions for Interior of the Earth to boost your fundamental clarity and excel in the 2025-26 exam.


Get a clear breakdown of earthquake waves, volcanic landforms, and sources of information about the earth’s interior. Using NCERT-based study material makes complex topics simple, fostering exam confidence and better marks in class tests.


Consistent revision of exercise-based answers will reinforce your memory. Focus on diagrams, terminology, and the processes explained to ensure you’re fully prepared to answer any question from this chapter in the final exam.


CBSE Class 11 Geography Chapter-wise NCERT Solutions



CBSE Class 11 Geography Study Materials

FAQs on NCERT Solutions For Class 11 Geography Chapter 3 Interior of the Earth - 2025-26

1. What is the structure and composition of Earth's interior according to Class 11 Geography Chapter 3 NCERT Solutions?

The structure of Earth's interior is divided into three main layers, each with distinct composition and properties:

- Crust: Outermost, thin, solid layer made of rocks (continental and oceanic types).
- Mantle: Thick middle layer beneath the crust, mainly silicate minerals rich in iron and magnesium.
- Core: Central layer, divided into outer (liquid) and inner (solid), composed mostly of iron and nickel.

This classification in NCERT Solutions for Class 11 Geography Chapter 3 helps students remember definitions, diagrams, and supports scoring better in CBSE exams.

2. How can students use stepwise NCERT Solutions to score full marks in Geography Chapter 3 exams?

Stepwise answers follow CBSE marking scheme and improve clarity for examiners. To score full marks:

- Begin with a definition or introduction.
- Present each point in logical order.
- Use diagrams and label them clearly.
- Highlight keywords and main concepts.
- Conclude with a summary.

Presenting solutions in structured steps ensures no marks are missed for correct process or partial knowledge.

3. Which types of questions are usually asked from Chapter 3 – Interior of the Earth in school exams?

CBSE and school exams often ask the following from Interior of the Earth:

- Short answer questions (definitions, layers of the earth)
- Diagram-based questions (label crust, mantle, core)
- Long answer questions (explain composition, features, significance)
- MCQs and worksheet questions (facts and concepts)

Using NCERT solutions helps students prepare for each type with accurate, exam-ready responses.

4. Are diagrams or definitions mandatory in NCERT Geography answers for Chapter 3?

Including diagrams and precise definitions is strongly recommended in Geography exams for Chapter 3:

- Diagrams (e.g., labelled structure of Earth) often carry separate marks.
- Definitions make your answers concise and to the point.
- Combining both ensures better scores as per CBSE marking scheme.

5. How should one structure long answers about 'Interior of the Earth' for maximum marks?

For long answer questions in Geography Chapter 3, use the following format:

- Start with an introduction to the topic.
- Divide the main body into subsections (e.g., structure, composition, features).
- Add labelled diagrams.
- Use bullet points or paragraphs with key points.
- End with a conclusion or importance.

This organisation matches CBSE standards and maximises mark allocation per step.

6. Where can I download the free PDF of NCERT Solutions for Class 11 Geography Chapter 3 Interior of the Earth?

You can access or download the free PDF of NCERT Solutions for Class 11 Geography Chapter 3 from trusted educational websites that specialise in NCERT and CBSE resources. Look for platforms offering chapterwise, stepwise solutions compliant with the current (2025–26) syllabus for effective offline revision.

7. What are the key definitions and formulae to remember from NCERT Class 11 Geography Chapter 3?

Essential definitions and terms you must remember include:

- Crust: Earth's outermost solid layer
- Mantle: Middle, viscous layer
- Core: Central, metallic layer
- Mohorovičić Discontinuity (Moho): Boundary between crust and mantle
- Gutenberg Discontinuity: Boundary between mantle and core

No major formulae but pay attention to terms and their locations on diagrams for CBSE Geography answers.

8. What common mistakes should students avoid when answering questions about the earth's interior?

Students should avoid these mistakes for full marks:

- Mixing up the order of Earth's layers (crust, mantle, core).
- Incorrect or missing diagram labels.
- Writing vague or incomplete definitions.
- Ignoring important boundaries (Moho, Gutenberg).
- Not following stepwise presentation as per NCERT solutions.

Following CBSE guidelines ensures accuracy and prevents loss of marks in exams.

9. Are NCERT Solutions enough for Class 11 Geography exams?

NCERT Solutions form the foundation for CBSE Class 11 Geography exams:

- They cover all textbook concepts and exercises.
- Stepwise solutions match the marking scheme.
- For higher scores, supplement with exemplar, MCQs, and previous year questions.

Rely on NCERT solutions as your base and practice extra problems for perfection.

10. How can I learn and revise diagrams or map labelling for Chapter 3 effectively?

For neat diagrams and map labelling in Chapter 3:

- Practice drawing Earth's structure regularly.
- Always use a pencil, ruler, and keep labels horizontal.
- Indicate all boundaries and layers clearly.
- Use separate lines or arrows for clarity.
- Revise labelling conventions and terms from NCERT solutions.

This improves recall and scoring in CBSE Geography practicals and theory exams.