Class 7 Geography Chapter 2 Inside Our Earth Extra Questions and Answers
Class 7 Geography Chapter 2 Inside Our Earth extra questions and answers available here in PDF format. Solving class 7 extra questions help students to revise the Chapter most competently. We prepared these questions as per the latest NCERT book and CBSE syllabus. Practicing these extra questions before the exam will ensure excellent marks in the exam.
Inside Our Earth Class 7 Geography Extra Questions and Answers
Very Short Extra Questions and Answers
1: Our earth constantly undergoing changes inside and outside. ( T/F)
Answer: True
2: The upper most layer of the earth surface is called the __________
Answer: Crust
3: The oceanic crust mainly consist of __________ and __________
Answer: Silica and Magnesium
4: Any natural mass of mineral matter that makes up the earth’s crust is called __________
Answer: Rock
5: Grinding stones used to prepare paste/powder of spices and grains are made of sedimentary. (T/F)
Answer: False
6: The radius of the earth is __________ km.
Answer: 6371
7: The deepest mine of the world is in which country.
Answer: South Africa
8: The upper crust is made up of minerals like silicon and aluminium while lower constitutes silicon and magnesium. (T/F)
Answer: True
9: Deccan plateau is made up of …………………rocks.
Answer: Basalt
10: Is the earth is a dynamic planet?
Answer: Yes
11: What temperature found at the core?
Answer: 5000 degree
12: The three layer of earth mantle is the thinnest among them.(T/F)
Answer: False
17: The inner most layer is the core with a radius of about __________ km.
Answer: 3500 km
18. Give an example of extrusive igneous rocks.
Answer: Basalt
Short Extra Questions and Answers
1. What is the radius of earth?
Answer: The radius of the earth is 6371 km.
2. What is the core of the earth made up of?
Answer: It is mainly made up of nickel and iron.
3. What is the innermost layer of the earth?
Answer: The innermost layer of the earth is the core.
4. Name the monument which is made of red sandstone?
Answer: The Red Fort is made of red sandstone.
5. What are the three layers of the earth?
Answer: The three layers of the earth are crust, mantle and core.
6. What is crust?
Answer: The uppermost layer over the earth’s surface is called the crust.
7. What is the uppermost layer of the Earth called?
Answer: The uppermost layer of the Earth is called crust.
8. What is the Latin word for igneous?
Answer: Latin word for igneous is Ignis meaning fire.
9. What is the Latin word for sedimentary?
Answer: Latin word for sedimentary is sedimentum which means settle down.
10. What is the Greek word for metamorphic?
Answer: Greek word for metamorphic is metamorphose meaning change of form.
11. What are the main mineral constituents of the continental mass?
Answer: The main mineral constituents of the continental mass are silica and alumina.
12. What is a rock?
Answer: Any natural mass of mineral matter that makes up the earth’s crust is called a rock.
13. Name three types of rocks.
Answer: There are three major types of rocks: igneous rocks, sedimentary rocks and metamorphic rocks.
14. How much of the earth is crust, mantle and core?
Answer: The crust forms only 1 per cent of the volume of the earth, 84 per cent consists of the mantle and 15 per cent makes the core.
15. What makes up the crust of the earth?
Answer: The earth’s crust is made up of various types of rocks such as igneous, metamorphic, and sedimentary rocks.
16. What are fossils?
Answer: The remains of the dead plants and animals trapped in the layers of rocks are called fossils.
17. What are metamorphic rocks?
Answer: When the igneous and sedimentary rocks are subjected to heat and pressure they change into metamorphic rocks.
18. What are igneous rocks?
Answer: When the molten magma cools, it becomes solid. Rocks thus formed are called igneous rocks.
19. What are minerals?
Answer: Minerals are naturally occurring substances which have certain physical properties and definite chemical composition.
20. Limestone is changed into marble. Give reason?
Answer: Marble is a metamorphic rock that forms when limestone is subjected to great heat and pressure.
21. Write about the deepest mine in the world.
Answer: The deepest mine in the world, is in South Africa. It is about 4 km. deep. In search for oil engineers have dug a hole about 6 km. deep.
22. Why we cannot go to the centre of the earth?
Answer: To reach to the centre of the earth we will have to dig a hole 6000 km. deep on the ocean floor. This is not possible, so we cannot go to the centre of the earth.
23. What do you mean by a rock cycle?
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.
24. What happens to igneous and sedimentary rocks when they are subjected to great heat and pressure?
Answer: Igneous and sedimentary rocks change into metamorphic rocks under great heat and pressure.
Long Extra Questions and Answers
1. How are minerals useful to mankind?
Answer: Minerals are useful to humankind in the following ways:
- Some are used as fuels. For example, coal, natural gas and petroleum.
- They are also used in industries – iron, aluminium, gold, uranium, etc, in medicine, in fertilisers, etc.
2. What are the uses of rocks?
Answer: Uses of rocks
- The hard rocks are used for making roads, houses and buildings.
- Stones are used in many games. For example, seven stones (pitthoo), hopscotch (stapu/kit kit), five stones (gitti).
3. How are extrusive and intrusive rocks formed?
Answer: Extrusive rock- When molten lava 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 grained structure.
Intrusive rocks – Sometimes the molten magma cools down deep inside the earth’s crust. Solid rocks so formed are called intrusive igneous.
4. Differentiate between sial and sima.
Answer:
| Sial | Sima |
| The main mineral constituents of the continental mass are silica and alumina. It is thus called sial (si-silica and al-alumina). | The oceanic crust mainly consists of silica and magnesium; it is therefore called sima (si-silica and ma-magnesium) |
5. Sedimentary rocks are formed from sediments. Give reason.
Answer: Rocks roll down, crack, and hit each other and are broken down into small fragments. These smaller particles are called sediments. These sediments are transported and deposited by wind, water, etc. These loose sediments are compressed and hardened to form layers of rocks. These types of rocks are called sedimentary rocks.
6. What do you know about earth’s interior?
Answer: The earth is made up of several concentric layers with one inside another.
Crust – The uppermost layer over the earth’s surface is called the crust. It is the thinnest of all the layers. It is about 35 km. on the continental masses and only 5 km. on the ocean floors.
Mantle – Just beneath the crust is the mantle which extends up to a depth of 2900 km. below the crust.
Core – The innermost layer is the core 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.
7. Write a note on various types of rocks?
Answer: There are three major types of rocks: igneous rocks, sedimentary rocks and metamorphic rocks.
Igneous rocks: When the molten magma cools, it becomes solid. Rocks thus formed are called igneous rocks. They are also called primary rocks. There are two types of igneous rocks: intrusive rocks and extrusive rocks.
- Extrusive igneous rocks – When molten lava 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. For example, basalt.
- Intrusive igneous rocks – Sometimes the molten magma cools down deep inside the earth’s crust. Solid rocks so formed are called intrusive igneous rocks. Granite is an example of such a rock.
Sedimentary rocks: Rocks roll down, crack, and hit each other and are broken down into small fragments. These smaller particles are called sediments. These sediments are transported and deposited by wind, water, etc. These loose sediments are compressed and hardened to form layers of rocks. These types of rocks are called sedimentary rocks. For example, sandstone is made from grains of sand.
Metamorphic rocks: Igneous and sedimentary rocks can change into metamorphic rocks under great heat and pressure. For example, clay changes into slate and limestone into marble.