Our Environment
I. Choose the correct answer.(1M)
1. The thinnest layer of the earth is the
a. crust
b. mantle
c. outer core
d. inner core
2. The average radius of the mantle is about
a. 2,300 km
b. 2,900 km
c. 3,500 km
d. 3,900 km
3. What is the other name of core?
a. Lithosfphere
b. Asthenosphere
d. Biosphere
c. Barysphere
4. Which layer of the earth is made up of iron and nickel?
a. Core
b. Crust
c. Mantle
d. Lithosphere
5. Granite, chalk, clay and salt are examples of
a. rocks
b. minerals
c. fossils
d. metals
6. The rocks which are formed from molten magma are called ________ rocks
a. sedimentary
b. igneous
c. metamorphic
d. metallic
7. The fossil fuels are found in ________ rocks
a. igneous
b. sedimentary
c. metamorphic
d. volcanic
8. Which of the following rocks is not a metamorphic rock?
a. Quartzite
b. Marble
c. Granite
d. Slate
II. Fill in the blanks.(1M)
9. The average density of the earth is about _____
10. The solid outermost layer of the earth is called _______
11. Limestone is metamorphosed into _____
12. The rock cycle has neither a _______ nor an _____
II. Answer the following questions.(1M)
1.What is called the material made up of silica and magnesium?
2.What is called the material of the earth crust ?
3.Name the main types of rocks?
4.What is intrusive rocks?
5.What is extrusive rocks?
6.What is known, the change of one type of rock into another?
7.Salt is an example of chemical formed in which rock?
8.Who is called geographer ?
9. What is called, the one study the interior of earth?
10.Which has neither a beginning nor an end?
11.In to what lime stone is metamorophosed into what?
12.What is the solid outermost layer of the earth called?
13.What is the average density of the earth ?
14.Which is the thinnest layer of the earth?
15. What is the average radius of the mantle?
16.What is the other name of core ?
17.Which layer of the earth is made up of iron and nickel?
18.Granite, chalk, clay and salt are examples of which rock?
19.Which rocks which are formed from molten magma first?
20.In which rock the fossil fuels are found?
III. Answer the following questions.(2M)
1.Name the main types of rocks with one example of each?
2.How are extrusive and intrusive igneous rocks formed?
3.Hoe are metamorphic rocks formed?
4.How are rocks and minerals useful to us?
5.Write about crust and core?
IV. Answer the following questions.(4M)
1.What do you know about the structure of the earth?
2.What are the main features of the mantle and the core?
3.What are the main characteristics of sedimentary rocks?
4.Explain the working of the rocks cycle?
5.Why can’t we go to the centre of the earth?