Inside Our Earth | Geography VII | Class 7th | Questions and Answers

 

JANDKNCERT | Social Science | Our Environment

Inside Our Earth | Geography VII | Class 7th | Questions and Answers

 

Chapter 2: Inside Our Earth

1. Answer the following questions

Question (i): What are the three layers of the earth?
Answer: The three layers of the Earth are:
(i) Crust
(ii) Mantle
(iii) Core

Question (ii): What is a rock?
Answer: A rock is a natural mass of mineral matter that makes up the Earth’s crust. Rocks can be of different color, size, texture, and composition.

Question (iii): Name three types of rocks.
Answer: The three types of rocks are:
(i) Igneous rocks
(ii) Sedimentary rocks
(iii) Metamorphic rocks

Question (iv): How are extrusive and intrusive rocks formed?
Answer:
(i) Extrusive rocks are formed when molten lava comes out on the Earth’s surface, cools rapidly, and solidifies.
(ii) Intrusive rocks are formed when molten magma cools down slowly inside the Earth’s crust, forming large grains.

Question (v): What do you mean by a rock cycle?
Answer: The rock cycle is the continuous process of transformation of rocks from one type to another. For example, igneous rocks can become sedimentary or metamorphic, and vice versa.

Question (vi): What are the uses of rocks?
Answer: Rocks are used in many ways:
(i) For making roads and buildings
(ii) As raw materials in industries
(iii) For making cement and other construction materials
(iv) Some rocks contain minerals that are valuable resources

Question (vii): What are metamorphic rocks?
Answer: Metamorphic rocks are those that are formed when existing rocks are subjected to great heat and pressure, which changes their form. Example: Limestone changes into marble.

2. Tick the correct answer

Question (i): The rock which is made up of molten magma is
Answer: (a) Igneous

Question (ii): The innermost layer of the earth is
Answer: (b) Core

Question (iii): Gold, petroleum and coal are examples of
Answer: (b) Minerals

Question (iv): Rocks which contain fossils are
Answer: (a) Sedimentary rocks

Question (v): The thinnest layer of the earth is
Answer: (a) Crust

3. Match the following

Question	Answer
(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

4. Give reasons

Question (i): We cannot go to the centre of the earth.
Answer: We cannot go to the centre of the Earth because it is extremely hot and has very high pressure, making it impossible for humans to reach there with current technology.

Question (ii): Sedimentary rocks are formed from sediments.
Answer: Sedimentary rocks are formed when small pieces of rocks, minerals, and organic materials (called sediments) are deposited in layers, pressed, and hardened over time.

Question (iii): Limestone is changed into marble.
Answer: Limestone is changed into marble due to high heat and pressure acting on it over a long period, which transforms its structure and appearance.