10th Class Science Our Environment Depletion of Ozone Layer

       Depletion of Ozone Layer

Ozone is a molecule made up of 3 molecule of oxygen atoms combined together. It is also poisonous in nature. It is formed in the upper layer of the atmosphere by the action of ultraviolet radiation on oxygen gas. The high energy ultraviolet radiations from the Sun splits oxygen gas into free oxygen atoms. Since these oxygen atoms are very reactive, it get combine with oxygen molecules to form ozone molecules.

Thus, the layer of \[{{\mathbf{O}}_{3}}\] molecule formed in the upper atmosphere. This protect us from the harmful ultraviolet radiation, and is called ozone layer. These harmful ultraviolet radiation can cause skin cancer and can also damage our eyes by causing an eye diseases, called cataract. It also destroy our immune system. Hence we can say that ozone layer is very useful to us and is also very essential for the earth's life forms. In recent past it has been found that the ozone layer is depleting and hole has appeared in the polar region of the ozone layer, which is a matter of great concern. The main reason for the depletion of ozone layer is the release of chlorofluorocarbon (CFC). This CFC is widely used in refrigerator and other coolants and this CFC reacts with ozone layer and gradually destroy it and thus leading to its depletion.

       Identify the biodegradable waste among the following:

(a) D. D. T.

(b) Plastic

(c) Glass

(d) Jute

(e) None of these

Answer: (d)

       There are two components of ecosystem, one is biotic and other is abiotic. Which one among the following is a biotic component of the ecosystem?

(a) Air

(b) Plant

(c Water

(d) Land

(e) None of these

Answer: (b)

         Which one of the following is not a terrestrial ecosystem?

(a) Forest

(b) Desert

(c) Grass Land

(d) River

(e) None of these           

Answer: (d)

         There are some organisms which manufacture their own food using simple inorganic substance and sunlight. Identify the organism among the following which does this work?

(a) Blue Green Algae

(b) Goat

(c) Bacteria

(d) Virus

(e) None of these

Answer: (a)

         Which one among the following is a lotic ecosystem?

(a) Pond

(b) Swamp       

(c) River

(d) Land

(e) None of these

Answer: (d)

• Every ton of recycled office paper saves 380 gallons of oil.
• Homeowners use up to 10 times more toxic chemicals per acre than farmers
• Every day 40,000 children die from preventable diseases
• Fibre optics, made of glass, are being used to replace copper cables throughout the world.

• Ecosystem consists of biotic and abiotic components.
• Biotic components includes all living organisms, plants and animals.
• The ultimate source of energy for all the living organisms is Sun.
• Human activities have impact on the environment.
• The thick layer of \[{{\mathbf{O}}_{3}}\] molecule in the upper layer of the atmosphere is ozone layer.
• The ozone layer protects us from the harmful ultraviolet radiations which can cause skin cancer and many other harmful diseases.
• The gas which cause the depletion of ozone layer is CFC.
• The disposal of waste material cause environmental pollution.