Question

In atmosphere, Ozone hole refers to
(A) hole in ozone layer
(B) Decrease in ozone layer thickness in troposphere
(C) Decrease in thickness of ozone layer in stratosphere
(D) Increase in the thickness of ozone layer in troposphere

Answer 1

Hint: The term ozone hole is given by the term atmospheric depletion. Ozone is a gas layer that is present in the upper atmospheric layer. It acts as a protective layer and sheath to the earth and prevents some hazardous sun rays from entering the inner layer of the atmosphere.

Complete Answer:
Chlorofluorocarbons (CFC's) are widely used as refrigerants. CFCS discharged in the lower part of the Atmosphere move upward and reach the stratosphere. In the stratosphere, UV rays act on them releasing chlorine atoms. Chlorine reacts with ozone in a cinematic method converting into oxygen. One active chlorine can destroy 50 molecules of ozone in one month and about 1 lac ozone molecules during its stay in the stratosphere.

Now let us gather information about given options :
A. Hole in ozone layer : ozone hole exactly means hole in ozone layer but here it is not defined that hole occurs in which layer of atmosphere whether troposphere or stratosphere.
B. Decrease in ozone layer thickness in troposphere : ozone hole means depletion of ozone layer but not in troposphere but in stratosphere due to large scale air circulation patterns in the lower part of the stratosphere move ozone towards the poles where the ozone concentration rises.
C. Decrease in thickness of ozone layer in stratosphere : Ozone holes can be given name to the depletion of the ozone layer which is present in the upper atmosphere i.e. stratosphere at the polar region of earth. Thus this option is correct.
D. Increase in the thickness of the ozone layer in the troposphere : ozone hole means depletion and decrease of thickness and not increase . As if the ozone layer increases it prevents earth atmosphere. The ozone hole doesn't stop the radiation which is harmful to living things present on earth Our required option is c Decrease in thickness of ozone layer in stratosphere

Note: UV radiation of wavelength shorter than UV-B, are almost completely absorbed by Earth's atmosphere, given that the ozone layer is intact. UV-B damages DNA and mutation may occur. It causes aging of skin, damage to skin cells and various types of skin cancers. In the human eye, cornea absorbs UV-B radiation and a high dose of UV-B causes inflammation of cornea called snow-blindness, cataract, etc. Such exposure may permanently damage the cornea.