Tag: causes of resource depletion

Questions Related to causes of resource depletion

Read the following statements and select the correct option.


Statement 1: Ozone layer present in the stratosphere protects the living organisms from harmful UV rays coming from the sun by absorbing nearly all of them.

Statement 2: Ozone formed in the troposphere by photochemical reactions as a result of human activities which is harmful to all living organisms.

  1. Both statements 1 and 2 are correct.

  2. Statement 1 is correct but statement 2 is incorrect.

  3. Statement 1 is incorrect but statement 2 is correct.

  4. Both statements 1 and 2 are incorrect.


Correct Option: A
Explanation:

'Good ozone' is found in the upper part of the atmosphere called the stratosphere and it act as a shield by absorbing ultraviolet radiations from the sun. UV rays are, highly injurious to living organisms. 'Bad ozone' is formed in the lower part of atmosphere called troposphere and it harms plants and animals.

The major ozone depleting substance out of the following is _____________.

  1. $ { CFC }{ s } $

  2. $ { O } _{ 2 } $

  3. Nitrogen

  4. All of these


Correct Option: A
Explanation:

Ozone-depleting substances (ODS) are substances that react with ozone present in the stratosphere and destroy the same. The major Ozone-depleting substances are chlorofluorocarbons (14% of total depletion), nitrogen oxides (3.5% depletion), sulphur dioxide, halon, carbon tetrachloride, methyl chloroform, chlorine, etc.

Ozone depletion is occurring widely in ______________.

  1. Troposphere

  2. Stratosphere

  3. Ionosphere

  4. All of these


Correct Option: B
Explanation:

Ozone depletion is occurring widely in the stratosphere, particularly marked over the Antarctic region.

So, The correct answer is (B)- Stratosphere.

Increasing skin cancer and high mutation rate are the result of _______________.

  1. Ozone depletion

  2. Acid rain

  3. $CO$ pollution

  4. $ { CO } _{ 2 } $ pollution


Correct Option: A
Explanation:

Ozone depletion occurs widely in the stratosphere due to an increased amount of $ { CFC }{ s } $ which causes various types of skin cancer and mutations.

So, The correct answer is (A)- Ozone depletion.

The maximum hole of ozone is found over ______

  1. Arctic zone

  2. Antarctic zone

  3. Tropical zone

  4. Subtropical zone


Correct Option: B
Explanation:
Ozone-depleting substances are present throughout the stratospheric ozone layer because they are transported great distances by atmospheric air motions. The severe depletion of the Antarctic ozone layer known as the “ozone hole” occurs because of the special atmospheric and chemical conditions that exist there and nowhere else on the globe. The very low winter temperatures in the Antarctic stratosphere cause polar stratospheric clouds (PSCs) to form. Special reactions that occur on PSCs, combined with the relative isolation of polar stratospheric air, allow chlorine and bromine reactions to produce the ozone hole in Antarctic springtime. 
So, the correct answer is 'Antarctic zone'.

The ozone layer in earth's atmosphere is crucial for human survival because it

  1. Has ions

  2. Reflects radio signals

  3. Reflects ultraviolet rays

  4. Reflects infrared rays


Correct Option: C
Explanation:

An ozone layer, present in the stratosphere, reflects the ultraviolet rays emitted by the sun and thus it prevents us from skin diseases and mutation.

So, the correct answer is option C.

The main factor responsible for the depletion of ozone layer is addition of _____in the atmosphere.

  1. $Mn$

  2. $Cl$

  3. $Na$

  4. $Co$


Correct Option: B
Explanation:

The main factor responsible for the depletion of ozone layer is addition of Cl in the atmosphere.
Each Cl atom can destroy as many as 100,000 ozone molecules. Cl atoms comes from chlorofluorocarbons.

In which of the following year, the depletion of the ozone layer have been noticed?

  1. 1979

  2. 1980

  3. 1981

  4. 1982


Correct Option: B
Explanation:

The depletion of the ozone layer was noticed in the year 1980.
The large scale destruction of the stratospheric ozone first came into focus in 1987 through the experiments in antarctica.

Maximum threat to the world is from

  1. Global warming

  2. Ozone hole

  3. Water pollution

  4. Soil erosion


Correct Option: B
Explanation:

Maximum threat to the world is from ozone layer which is found in the stratosphere. This layer acts as a shield absorbing UV radiations from the sun. For the ozone layer to be intact there has to be a balance between the production and degradation which has been disturbed by the CFCs used in refrigerators. The F and Cl, which are released by these compounds results in the thinning out of the ozone layer also known as the ozone hole. It causes threat to life and environment as it leads to skin aging and cancers, snow blindness, cataract, melting of polar ice caps, global warming etc.

So, the correct answer is 'Ozone hole'

UV light radiation cause

  1. Formation of pyrimidines

  2. Photodynamic action

  3. Breakage of hydrogen bonds in DNA

  4. Protein denaturation


Correct Option: C
Explanation:

The UV radiations can cause mutation in the cells by altering the DNA. These are ionising radiations which can damage the structure of the DNA molecule. The UV rays can result in the formation of thymine dimers or split the hydrogen bonding. This results in distortion in the structure of DNA and the cell dies due to malfunctioning of the genetic material. 

Thus, the correct answer is option C.