NCTB Class 9-10 Science Chapter 8 “Our Resources” Solution
Bangladesh Board Class 9-10 Science Solution Chapter 8 Our Resources Solution Exercises Question and Answer by Experienced Teacher.
NCTB Solution Class 9-10 Chapter 8 “Our Resources”:
|NCTB Bangladesh Board|
9 – 10 (Nine – Ten Classes)
Multiple choice questions.
1) Which one is the softest mineral?
a) Diamond b) talc
c) silica d) Limestone
2) Soil of the subsoil layers
i) Full of rock particles
ii) Enriched with minerals
iii). Enriched with organic substances
Which of the following is correct ?
I and ii b. I and iii
Ii and iii d. I, ii and iii
Answer:- c) ii and iii
- Near the nuclear power plant in Tokyo . No plant grows well other than mashroom.
3) Which is abundant in that soil?
c) Organic substances
d) Radioactive substances
Answer:- d) radioactive substances
4) In which soil crop production will be good?
i) Soil containing sand and minerals
ii) soil containing minerals
iii) soil containing sand and slit
iv) soil containing sand, slit, and clay.
Answer:- iv) soil containing sand, slit, and clay.
- Answer questions 5 and 6 from the picture:
5) Which layer contains rock particles?
a) X layer. b) Y layer
c) Z layer. d) Layer below Z
Answer:- d) layer below Z
6) Crop production is good In the top most layer because this soil
I) Contains organic substances
II) Contains minerals
III) Contain rock particles
IV) Contains microorganisms
Answer:-i) contains organic substances
Que. 1] soil in the area where Bokul live contain rock and minerals. The size of the soil particles is big. Water draining is very fast, on the other hand soil in the area where shaheen lives has small particles but enriched withorganic and mineral substances.
1) What is aeration?
Answer:-Along with the water , the pores in the soil may retain gaseous substances which are usually nitrogen, oxygen, and carbon dioxide . Interestingly exchange occurs between the gaseous substances present in the air that in soil . The process is called soil aeration.
2) How does horizon form ?
Answer:- the soil composition in all depth is not identical. It is seen that is divided into four horizontal layers. Each layer is called a Horizon. The horizon at the top is known as horizon A or top soil. It is usually sandy. Minerals are not found in this layer. Dead plats and animals starts here and products of biodegradation, especially humus, and other organic substances stay in this layer.
Second layer is sub- soil or Horizon B. Small amount of humus is found in this layer, full of minerals are there.
Third layer of soil is Horizon C . Contains rocks and complex chemical reaction. Below the horizon C very hard parent rocks are present
3) Explain the type of soil in bokuli’s area?
Answer:-type of soil in Bokuli’s area is sandy soil as it has large particle size and very high drainage. Sandy soil consist of small rocks and minerals. Presence of humus in the sandy soil favours cultivation. Due to over drainage plants lack water particularly in summer. So the plant need huge amount of water to grow well in sandy soil.
4) Soil of which area will result in better cultivation? Justify your opinion.
Answer:- soil of saheen has small particles but enriched with organic and mineral substances, this soil will result in better cultivation. As the particles size is small in slit soil they can be present in water as suspended matter which at a stage deposit as sediment on the land. Slit soil contains organic substances and minerals like quartz. Like sandy soil it is also granular and contains a large amount of plant nutrients.
Que 2] see the figure and answer the question .
1) What is petroleum?
Answer:-petroleum is a mineral oil, i.e the liquid fuel that is found in the mine . Usually natural gas and petroleum oil are found together in the ore. Although propane and butane are gaseous substances in normal condition (25°c and 1 atmospheric pressure ) they are compressed to liquid at higher pressure and that is why they are included in petroleum. Gasoline, diesel, and kerosene are also petroleum.
2) What is meant by fossil fuels ?
Answer:-A natural fuel such as coal or oil which was formed millions of years ago from dead animals or plants in the ground are known as fossil fuels. These are formed by natural processes.
3) How the fuel in fig A processed to make it suitable for use ? Explain
Answer:- the natural gas used in fig. A i.e CNG is methane (CH4 ) . However a small substances of other amount is also present in that I.eethene, propane and butane. And small amount of carbon dioxide, nitrogen, hydrogen sulfide , hydrogen, argon and helium. The processing of natural gas and petroleum is a complex industrial process. Which is carried out in several steps, in gas well petroleum oil is separated from oil . The benzene and butane present in gas are compressed and separated. Then water is removed by dehydration process. Impurities are removed. The gas mixture obtained at this stage contains nitrogen which is separated. Then the gas obtained is pure methane gas.
4) To produce energy shown in fig. B which one is economical between A and C? Justify your answer.
Answer:-To produce energy shown in fig. B the economical process between A and C is C. Coal is black or blackish brown sedimentary rock. The main element in coal is carbon. ( C ) . Based on the geographical location coal contains variable amount of hydrogen, sulphur, oxygen, and nitrogen in addition to carbon. It is burnable it is used as fuel. Most of the countries use coal for producing electricity. It is found in abundance it will be economical.