NCERT Solutions Class 7 Geography Chapter 2 Inside Our Earth
NCERT Solutions Class 7 Geography Chapter 2 Inside Our Earth: National Council of Educational Research and Training Class 7 Geography Chapter 2 Solutions – Inside Our Earth. NCERT Solutions Class 7 Geography Chapter 2 PDF Download.
NCERT Solutions Class 7 Social Science Geography Chapter 2: Overview
Board |
NCERT |
Class |
7 (Seven) |
Subject |
Social Science |
Book Name |
Geography |
Chapter |
02 (Two) |
Chapter Name |
Inside Our Earth |
Topic |
Exercise Solutions |
NCERT Solutions Class 7 Geography Chapter 2 – Inside Our Earth
1) Answer the following questions:
(i). What are the three layers of the earth?
Answer
The three layers of the Earth are
- Crust(1st layer)
It’s the uppermost layer overthe Earth surface. It extends to 35 kilometres on the land mass and 5 km beneath the ocean floors.
- Mantle(2nd layer)
It is the layer beneath the crust. The mantle extends upto a depth of 2,900 kilometres.
- Core(3rd layer)
It is the innermost layer of the Earth andwith a radius of 3,500-kilometres.
(ii). What is a rock?
Answer
The uppermost layer includes all the solid material present on the Earth’s crust. Any natural group of mineral components that makes up the earth’s crust is called a rock. There are three types of rock:
- Igneous Rocks
- Sedimentary Rocks
- Metamorphic Rocks
(iii). Name three types of rocks.
Answer
The three types of rocks are:
- Igneous Rocks/Primary Rocks
After the molten magma cools, it becomes solid Rock, thus the rock formed are called igneous rocks. There are two types of igneous rocks intrusive rocks and extrusive rocks
- Sedimentary Rocks
When big rocks break down into smaller These smaller rocks are called sediments. This rocks are transported and deposited by factors like water and wind.
- Metamorphic Rocks
The Igneous and sedimentary rocks under great heat and pressure can change into metamorphic rocks.
(iv). How are extrusive and intrusive rocks formed?
Answer
- Intrusive Rocks
It is a type of Igneous rocks.
When the molten Magma cools down deep inside the earth’s crust, the rocks so formed are called intrusive rocks.
Example-Granite Rock
- Extrusive Rocks
When the molten lava comes out , reaches the earth’s surface and cools down to become a solid rock is called the Extrusive Rocks.
Example- Basalt Rock
(v). What do you mean by a rock cycle?
Answer
When rock changes to another type of rock under certain conditions in a cyclic manner (Wind, Rain, River, etc).This process of transformation of the rock from one to another is known as the rock cycle.
(vi). What are the uses of rocks?
Answer
The uses of rocks are
- Used to prepare paste/powder of spices and grains.
- Used for fuel pupose by humans and industries.
- Used in fertilizer and medicine.
- Used in buliding Road, House and bridge.
(vii). What are metamorphic rocks?
Answer
The Igneous and sedimentary rocks under great heat and pressure can change into metamorphic rocks .
Example-1.) Clay changes into slate
2.) Limestone into marble.
2) Tick the correct answer.
(i). The rock which is made up of molten magma is
(a) Igneous (b) Sedimentary (c) Metamorphic
Answer
(a) Igneous
Explanation: It is because the molten lava comes out or stays Inside the earth’s surface, it rapidly cools down and becomes solid thus rocks formed are called Igneous rocks.
(ii). The innermost layer of the earth is
(a) Crust (b) Core (c) Mantle
Answer
(b) Core
Explanation: It is because the radius of the core is 3500 km .
(iii) Gold, petroleum and coal are examples of
(a) Rocks (b) Minerals (c) Fossils
Answer
(b) Minerals
Explanation: Gold, petroleum and coal are examples of Minerals because it has certain physical properties and definite chemical composition.
(iv) Rocks which contain fossils are
(a) Sedimentary Rocks
(b) Metamorphic Rocks
(c) Igneous Rocks
Answer
(a) Sedimentary Rocks
Explanation: It is because these rocks contain fossils of plants, animals that once lived on them.
(v) The thinnest layer of the earth is
(a) Crust (b) Mantle (c) core
Answer
(a) Crust
Explanation: It is because it is about 35 km on the continental masses and only 5 kmon the ocean floors making it the thinnest layer.
(3). Match the following
(i) Core – (e) Innermost layer.
(ii) Minerals-(d) Has definite chemical composition.
(iii) Rocks- (b) Used for roads and buildings.
(iv) Clay- (f) Changes into slate.
(v) Sial- (c) Made of silicon and alumina.