Important Questions Class 8 Chapter 2 Geography Maharashtra Board

Imp Questions For All Chapters – Geography Class 8

Interior of the Earth

Short Questions 

1. What are the three main layers of the Earth?

• The three main layers of the Earth are the Crust, Mantle, and Core.

2. Which is the outermost layer of the Earth?

• The Crust is the outermost layer of the Earth.

3. What are the two types of crust?

• The two types of crust are Continental Crust and Oceanic Crust.

4. Which elements mainly compose the Earth’s core?

• The core is mainly composed of Iron (Fe) and Nickel (Ni).

5. Why is the upper mantle called the asthenosphere?

• The upper mantle is called the asthenosphere because it is semi-liquid and allows the movement of tectonic plates.

6. What is the approximate temperature at the Earth’s core?

• The temperature at the Earth’s core is around 5500°C – 6000°C.

7. Which seismic waves cannot pass through liquids?

• Secondary (S) waves cannot pass through liquids, proving that the outer core is liquid.

8. What is the function of the Earth’s magnetosphere?

• The magnetosphere protects the Earth from harmful solar winds and cosmic radiation.

9. What is the Conrad Discontinuity?

• The Conrad Discontinuity is the boundary between the continental and oceanic crust.

10. Why do earthquakes occur?

Earthquakes occur due to the movement of tectonic plates and release of energy in the Earth’s crust.

Long Questions 

1. What is the difference between continental crust and oceanic crust?

• The continental crust is thicker (30-45 km) and made of silica and aluminum (SIAL), whereas the oceanic crust is thinner (7-10 km) and composed of silica and magnesium (SIMA).

2. Why do scientists study seismic waves to understand Earth’s interior?

• Seismic waves change speed and direction when they pass through different layers, helping scientists determine the composition, density, and state of matter inside the Earth.

3. What is the role of magma chambers in volcanic eruptions?

• Magma chambers in the upper mantle (asthenosphere) store molten rock, which rises through the crust and erupts as lava during volcanic activity.

4.  How does the Earth’s magnetic field form?

• The movement of molten iron in the liquid outer core creates electric currents, which generate Earth’s magnetic field, protecting us from solar radiation.

5. What is the significance of the Moho Discontinuity?

• The Mohorovičić (Moho) Discontinuity is the boundary between the crust and mantle, marking a change in composition and density of Earth’s layers.

6. How does temperature change as we go deeper into the Earth?

• Temperature increases with depth, starting from normal surface temperatures to around 2500°C in the mantle and reaching up to 6000°C in the core.

7. Why is the inner core solid despite high temperatures?

• The inner core remains solid due to extreme pressure, which prevents the iron and nickel from melting, even at very high temperatures.

8. How does the crust differ from the mantle in composition and density?

• The crust is made of light materials like silica and aluminum, while the mantle is denser and consists of iron, magnesium, and silicate minerals.

9. Why is the Earth’s interior important for natural processes?

• The Earth’s interior controls volcanic eruptions, earthquakes, mountain formation, and plate tectonics, which shape the planet’s surface.

10. What is the role of gravitational force inside the Earth?

Gravitational force increases with depth but becomes zero at the Earth’s center, influencing the movement of magma and maintaining the structure of the planet.