Question

Ozone (O₃) layer is largely found in the stratosphere which is a part of our atmosphere from 12 km - 50 km above sea level. This region is called ozonosphere. Ozone is deadly poisonous at the ground level. Ozone is formed as a result of the following photochemical reaction. Ozone layer is a protective blanket around earth which absorbs most of the harmful U.V. (Ultraviolet) radiation of the Sun, thus, protecting the living beings of the Earth from health hazards like skin cancer, cataract in eyes, weaken immune system, destruction of plants etc. The decline of Ozone layer thickness is termed as OZONE HOLE.

1. The decline of Ozone layer thickness in Antarctica was first discovered in _____.

a. 1985

b. 1992

c. 1982

d. 1986

2. The substance which is chiefly responsible for the depletion of ozone layer is :

a. CFCs

b. CH₃

c. OH

d. DDT

3. Which of the following radiations is responsible for the conversion of atmospheric oxygen to ozone?

a. Gamma radiations

b. Cosmic radiations

c. Infrared radiations

d. Ultraviolet radiations

4. Depletion of ozone is mainly due to _____

a. chlorofluorocarbons

b. sulphur dioxide

c. acid rain

d. green house effect

5. The number of atoms of oxygen in ozone _____.

a. 1

b. 3

c. 4

d. 7

Answer 1

1. a. 1985

2. a. CFCs

3. d. Ultraviolet radiations

4. a. chlorofluorocarbons

5. b. 3