Inside Our Earth Extra Questions Chapter 2 Class 7 Geography
On this page you will find Chapter 2 Inside our Earth Class 7 Geography Extra Questions that will help you in covering all the essential topics present in the chapter. Extra Questions for Class 7 Geography is the best way through one can improve their marks and answer all the difficult questions that come in the exams.
Chapter 2 Inside Our Earth Very Short Answer Questions (VSAQs):
1. What is a rock?
Answer
Any natural mass of mineral matter that makes up the earth’s crust is called a rock.
2. The oceanic crust mainly consist of ______ and _____.
Answer
Silica and Magnesium.
3. The upper most layer of the earth surface is called the ______.
Answer
Crust.
4. The radius of the earth is ______ km.
Answer
6371.
5. Basalt is the example of which rocks.
Answer
Igneous.
6. What are the main elements of the core?
Answer
The main elements of the core are nickel (ni) and iron (fe) which in short are called nifi.
7. What are the main elements of the mantle?
Answer
The main elements of the mantle are silicon (si) magnesium (mg) which in short are called sima.
8. The deepest mine of the world is in which country.
Answer
South Africa.
9. What temperature found at the core?
Answer
5000 degree.
10. Deccan plateau is made up of _______ rocks.
Answer
Basalt.
11. Due to intense heat and pressure granite rocks changes into.
Answer
Gneiss.
12. Sedimentary Latin word sedimentum meaning _______.
Answer
Settle down.
13. Define rock cycle?
Answer
The process of transformation of the rock from one to another is known as rock cycle.
14. Core is made up of _______ and ______.
Answer
Nickel, iron.
15. What are three layers of the earth?
Answer
The three layers of the earth are—crust, mantle and core.
16. Why is limestone changed into marble?
Answer
Marble is a metamorphic rock resulting from the metamorphism of limestone, composed mostly of calcite.
Chapter 2 Inside Our Earth Short Answer Questions (SAQs):
1. How are extrusive and intrusive rocks formed?
Answer
Intrusive and extrusive rocks are types of igneous rocks which are formed when magma cools down and solidifies.
• Extrusive rocks: When the molten magma comes on the earth’s surface, it rapidly cools down and becomes solid. Rocks formed in such a way on the crust are called extrusive igneous rocks. They have a very fine structure. For example, basalt.
• Intrusive rocks: Sometimes the molten magma cools down deep inside the earth’s crust or surface. Solid rocks so formed are called intrusive igneous rocks. Since they cool down slowly, they form large grains. For example, granite.
2. What are metamorphic rocks?
Answer
Metamorphic rocks are actually igneous or sedimentary rocks which changed due to great heat and pressure. Small crystals combine together to form large crystals. The act of metamorphism takes hundreds of years. Examples—clay changes into slate and limestone changes into marble.
3. What is mantle?
Answer
It is an intermediate layer lies between the crust and the core of the earth .Its avg thickness is about 29,00 km. It is believed to consist of solid ultra basic rocks, rich in iron and magnesium.
4. What is the importance of outer crust to us?
Answer
The solidified outer crust of the earth is of great importance to us .This thin crust just like the skin of an apple, forms the stage on which human life and civilization have developed. It has the valuable soil and gives us most of our minerals.
5. What is the source of knowing of the layered structure of the earth?
Answer
The layered structure of the earth has been known on the basis of variation in temperature, pressure and the density of the material in the interior. The behaviour in the earth quake shock waves travelling from the centre of their origin in all directions has been much helpful to this end.
6. Give example of all the three major forms of rocks?
Answer
Igneous-granite, basalt
Metamorphic rocks- marble, slate, graphite
Sedimentary- limestone, sandstone.
7. What are the uses of rocks?
Answer
Rocks are very useful to man, used for making roads, houses and building. Rocks are the source of precious metals like gold, silver, and platinum. We use stone in many games. For example, seven stone, top scotch.
8. Distinguish between crust and core.
Answer
• Crust is the uppermost solid layer of the earth while core is the innermost layer.
• (ii) Crust is the thinnest of all the layers. It is about 35 km thick.
• The main elements of the crust are silicon, aluminium and magnesium while the main elements of the core are nickel and iron.
Chapter 2 Inside Our Earth Long Answer Questions (LAQs):
1. Describe the different layers of the earth.
Answer
The earth is made up of three concentric layers with one inside another—crust, mantle and core.
• Crust: It is the uppermost solid layer of the earth. It is the thinnest of all the layers. It is about 35 km on the continental masses and only 5 km on the ocean floor.
• Mantle—Below the crust of the earth lies a very thick layer called the mantle. It extends up to a depth of 2900 km below the crust. The main elements of this layer are silicon and magnesium and is called sima.
• Core—It is the innermost layer with a radius of about 3500 km. It is mainly made up of nickel and iron and is called nife. The central core has very high temperature and pressure.
2. Describe the rock-cycle with the help of a diagram.
Answer
One type of rock changes to another type under certain conditions in a cyclic manner. This process of transformation of the rock from one to another is known as the rock cycle which includes the following phases:
• These igneous rocks are broken into small particles that are transported and deposited to form sedimentary rocks.
• When the igneous and sedimentary rocks are subjected to heat and pressure, they change into metamorphic rocks.
• The metamorphic rocks which are still under great heat and pressure melt down to form molten magma.
• This molten magma again cools down and solidifies into igneous rocks.
This process continues to take place without a break.