![if !IE]> <![endif]>
Social Science : Geography
LITHOSHERE – I
IV. Answer in brief.
1. Write a brief note on the various spheres of the Earth.
Various spheres of the Earth:
• The Lithosphere is the solid outer part of the Earth.
• The Hydrosphere is the watery part of the Earth's surface including oceans, rivers, lakes and water vapour.
• The Atomsphere is a thin layer of gases that surrounds the earth.
• The Biosphere is the layer of Earth where life exists.
2. Mention the layers of the interior of the Earth.
The layers of the Interior of the Earth.
• The crust
• The mantle
• The core
3. Define plate tectonics :
• Tectonic plates in Lithosphere are divided into major and minor plates. These plates float over the mantle.
• The movement of tectonic plates is due to thermal energy from the mantle. Collisions of these plates produce mountain ranges and irregular surfaces.
4. What is Tsunami?
• Large seismically generated sea waves caused by Earthquakes, submarine explosions and land slides are 'Tsunami'. (Tsunami - a Japanese term for harbour waves)
• Tsunami travels at more than 500 km / hour. The length 600 km and the height 15 m.
5. What is a volcano? Mention its major components.
• Magma ( hot solid, liquid and gaseous materials), in the Earth's interior erupt out to the surface of the Earth crust through an opening is a 'volcano'.
The compoments of Volcanols
• Magma chambar
• Volcanic cone
6. What is an Earthquake and how it occurs?
• Earthquakes are generally caused by the sudden vibrations in the Earth's crust.
• The point of origin of an Earthquake is 'Focus' (Hypocenter).
• 'Epicentre' is a point on Earth's surface that lies directly above the focus.
7. What are seismic waves and Mention its types?
• Earthquakes generates 'seismic waves'. The nature, force and speed of these waves depend on the nature of the medium through which it passes.
Types of waves:
• Primary or ('P' waves)
• Secondary waves ('S' - waves)
• Surface waves ('L' - waves)
8. Write about the Pacific Ring of fire.
• The Pacific Ring of fire is the pacific plate meets many surrounding plates.
• The Ring of fire is the most seismically and volcanically active zone in the world.
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.