Reduction in thickness of ozone layer in the stratosphere

Reduction in thickness of ozone layer in the troposphere

Increase in concentration of ozone

Central Environmental and Public Health Engineering Research Institute

Centre for Environmental and Personal Health Research Institute

Central for Engineering and Public Health Report Institute

MCQ Questions for Class 12 Medical Biology Environmental Issues Quiz 5

Ultraviolet light causes

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Destruction of hydrogen bonds between complementary DNA strands
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Photodynamic action
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Sticky metaphases
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Formation of pyrimidines

For how long and at what temperature an experiment is run to determine the value of BOD of a water body?

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$10^oC$ for 10 days
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$20^oC$ for 5 days
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$20^oC$ for 2 days
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$5^oC$ for 20 days

Effect of today's radioactive fall out will be more on future children than on present-day children as

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Radiations have delayed effect
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Mutated genes are usually recessive
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Infant susceptibility to radiations
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Increase ofsusceptibility to radiations with age

What immediate hazard is likely to occur if the temperature of the earth rises by 5

$^oC$ ?

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Increase in productivity
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Melting of polar ice
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Destruction of phytoplanktons
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Inundation of coastal towns

What is the potential danger of greenhouse effect?

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Poor photosynthesis
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Heavy rainfall
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Coastal flooding
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More humidity in environment

Which of the following is the most dangerous environment hazard to mankind?

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Noise pollution
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Water pollution
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Nuclear winter
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Air pollution

When huge amount of CO

$_2$ is dumped into a river, the BOD will

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Increase
0%
Slightly decrease
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Remain unchanged
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Decrease

A rapid growth of photosynthetic algae in water develops 'bloom'. How would it affect the environment of water?

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The environment becomes comfortable for all forms of life.
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O $_2$ level is decreased or BOD becomes high.
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O $_2$ level of water is increased.
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Fish production is increased.

Which of the following is a weightless pollutant?

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Photochemical smog
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Heat, Sound and Radioactive waste
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SO $_2$ and NO $_2$
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Sewage and Exhaust emissions

Which of the following chemical is released by chlorofluorocarbon that is harmful to ozone ?

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Fluorine
0%
Sulphur dioxide
0%
Nitrogen peroxide
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Chlorine

Increase skin cancer and higher mutation rates are generally the consequences of

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CO $_2$
0%
Ozone depletion
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Biomagnification
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Acid rains

The measurement of rate of oxygen utilisation by a unit volume of water over a period of time is to measure.

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Biochemical oxygen demand
0%
Biosynthetic path
0%
Biogas generation
0%
Fermentation

Maximum threat to the world is from

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Global warming
0%
Ozone hole
0%
Water pollution
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Soil erosion

The ozone layer: Between 15 and 50 km above the earth is a thin layer of gas called 'ozone'. It protects the earth from most of the sun's harmful ultraviolet radiation. Too much radiation causes blindness in animals and skin cancer in people. In 1985, scientists discovered a hole in the ozone layer in the Antartica. They have recently discovered a smaller hole over the arctic. The ozone layer is also becoming thinner over other locations of the earth too. Scientists believe that over the last 10 years about 30% of the ozone layer has disappeared. This damage is caused by chemicals. Choose the right statement(s) from the following.

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The greenhouse effect would be more efficient and the temperature of earth would increase.
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CFCs would result in the depletion of the ozone layer.
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Infrared radiation from the sun would bombard earth.
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Ultraviolet radiation from the sun cannot enter earth.

Explanation

The presence of CFCs in the atmosphere results in the depletion of the ozone layer. They are used as coolants in refrigerators, coolers, etc. The CFCs causes the breaking of the ozone molecule which forms the oxygen radical and O

$_2$ . The depletion of the ozone layer results in the penetration of the harmful UV radiations from the sun into the Earth's atmosphere.

Thus, the correct answer is option B.

Which of the following enhances B.O.D. of water ?

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Sugar mill effluents
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Algae
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Sand
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Moss

World climate is threatened by increase in the concentration of

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Oxygen
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Nitrogen
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Water vapours
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Carbon dioxide

Measurement of rate of oxygen utilisation by a unit volume of water over a period of time is to measure

0%
Biochemical oxygen demand
0%
Biosynthetic pathway
0%
Biogas generation
0%
Fermentation

Ozone hole refers to

0%
Hole in ozone layer
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Reduction in thickness of ozone layer in the stratosphere
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Reduction in thickness of ozone layer in the troposphere
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Increase in concentration of ozone

The washing away or removal of soil from land is called

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Soil formation
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Soil erosion
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Crop rotation
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Recycling

Denitrification is caused by

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Pseudomonas
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Nitrobacter
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Nitrosomonas
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Azotobacter

Ozone is found in the atmosphere and helps to protect us from harmful radiation. Ozone is

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$\displaystyle { O }^{ 2- }$
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$\displaystyle { O }^{ - }$
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$\displaystyle \\ { O }_{ 2 }\\$
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$\displaystyle \\ { O }_{ 3 }\\$

Explanation

Ozone is an inorganic molecule formed by the three molecules of oxygen with the chemical formula O

$_3$ . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope O

$_2$ and more reactive molecule.

Plantation of saplings on a large scale is celebrated as:

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Afforestation day
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Vanamahotsava
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Deforestation day
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Plantation day

Explanation

$\textbf{Correct option:}$

$\textbf{(B)}$

$\textbf{Solution:}$

$\textbf{Option (A)}$

$\bullet$ Every year, Forestation Day is commemorated to raise awareness about the value of all sorts of forests and trees outside of them for future generations.

$\bullet$ It is observed on March 21st all across the world.

$\textbf{Option (B)}$

$\bullet$ Every year, for one week, Van Mahotsav is observed, during which millions of people plant trees in order to restore the woods and plantations that have been repeatedly damaged.

$\bullet$ Every year, from the 1st to the 7th of July, it is commemorated.

$\bullet$ Because this is the best season to plant trees, the celebration is held during the first week of July.

$\textbf{Option (C)}$

$\bullet$ The elimination of a forest or the cleansing of long-standing trees is referred to as deforestation.

$\bullet$ Trees are felled for the construction of residences and the sale of timber, among other things.

$\textbf{Option (D)}$

$\bullet$ Plantation Day is observed on March 21st to raise awareness about the necessity of tree planting.

$\bullet$ The primary goal of this day is to awaken people and make them aware of the value of trees in human life.

$\textbf{Thus the Correct option is (B)}$

UV light radiation cause

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Formation of pyrimidines
0%
Photodynamic action
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Breakage of hydrogen bonds in DNA
0%
Protein denaturation

The factor responsible for depletion of ozone layer is

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Excessive use of automobiles
0%
Excessive industrial units
0%
Excessive use of man made compounds containing chlorine and fluorine
0%
Excessive deforestation

Overall the contribution of carbon dioxide to global warming is

0%
20%
0%
14%
0%
6%
0%
60%

The presence of ozone in the atmosphere of earth

0%
Is advantageous since it supplies O $_2$ for people travelling in jets
0%
Helps in checking the penetration of ultraviolet rays to earth
0%
Hinder higher rate of photosynthesis
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Has been responsible for increasing the average global temperature in recent years

What are the advantages of reforestation?

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It helps to reduce the concentration of CO $_2$ in the environment.
0%
It has the potential to preserve endangered species.
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It can reverse the damage done by erosion.
0%
All of the above.

Explanation

Deforestation results in an increase in CO

$_2$ concentration in the atmosphere, greenhouse gasses like CO

$_2$ and methane significantly contribute to a changing climate. Reforestation involves the planting of the trees of same species. It is an effective method to reduce CO

$_2$ in the atmosphere, it also helps in restoring habitat loss and also helps in fighting against climate change and help in restoring endangered species from extinction.

Thus, the correct answer is option D.

What is reforestation?

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Cutting of trees.
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Restocking of the destroyed forests by planting new trees.
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Conversion of fertile soil into forest.
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Conversion of forest into fertile soil.

In reforestation, the planted trees should generally be of the same .................. , which were found in forests.

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Family
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Kingdom
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Species
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Class

Which of the following conditions lead to formation of ozone?

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When oxygen molecules absorb ultraviolet photons and undergo photolysis
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When carbon molecules absorb ultraviolet photons and undergo photolysis
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When oxygen molecules absorb ultraviolet electrons and undergo photolysis
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When oxygen molecules absorb ultraviolet neutrons and undergo photolysis

Explanation

$\textbf{Correct option: }$ A

$\textbf{Solution: }$

$\textbf{Option (A) }$

$\bullet$ The energetic ultraviolet photon splits an oxygen molecule to form ozone molecules is known as photolysis.

$\bullet$ It is assumed that the two resulting oxygen atoms will each form an ozone molecule.

$\bullet$ Ozone layer is responsible for protecting the earth's atmosphere from the harmful $\bullet$ Ultraviolet rays received from the sunlight.

$\bullet$ The thinning of the ozone layer is known as the ozone layer depletion that can result in the increase of the UV radiation reaching the earth's atmosphere.

$\bullet$ The major constituents responsible for ozone layer depletion are chlorofluorocarbons (CFCs) such as freons, halons, and other compounds.

Hence, the correct option is (A)

40 to 50% depletion in ozone layer occurs in the .......... polar region

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North
0%
South
0%
East
0%
West

Which of the following involves the clearing of the forest?

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Afforestation
0%
Deforestation
0%
Soil erosion
0%
None of the above.

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

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$Mn$
0%
$Cl$
0%
$Na$
0%
$Co$

Which of the following describes the destruction of the ozone by chlorofluorocarbons?

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CFC contains the chlorine molecule which reacts with ozone (O $_2$ ) molecule and splits into O $_2$ and O molecules
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Contains the chlorine molecule which reacts with oxygen (O $_3$ ) molecule and splits into O $_2$ and O molecules
0%
CFC contains the fluorine molecule which reacts with ozone (O $_3$ ) molecule and splits into O $_2$ and O molecules
0%
CFC contains the chlorine molecule which reacts with ozone (O $_3$ ) molecule and splits into O $_2$ and O molecules

Depletion of ozone layer is mainly due to

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Methane
0%
Carbon dioxide
0%
Chloroflorocarbons
0%
Nitrogen

Explanation

Depletion of ozone layer is mainly due to Chloroflorocarbons.
Note:
The following describes the destruction of the ozone by chlorofluorocarbons.
Chlorofluorocarbons contains the chlorine molecule which reacts with ozone (O

$_3$ ) molecule and splits into O

$_2$ and O molecules.
Chlorofluorocarbons are used in refrigerators, air conditioners and aerosol sprays. They damage the ozone layer of the atmosphere.

_____ shields the surface of the earth from ultraviolet (UV) radiation from the sun.

0%
Oxygen
0%
Nitrogen
0%
Ozone
0%
Carbon dioxide

The effects of radioactive pollutants depends upon

0%
Rate of diffusion
0%
Energy releasing capacity
0%
Rate of deposition of the contaminant
0%
All of the above

Radioactive fall out contaminates

0%
Air, soil and water
0%
Air and water both
0%
Soil only
0%
Both soil and water

Increased level of carbon dioxide in the atmosphere traps the heat rays reflected by the earth causing an increase in the temperature on the earth. This is

0%
Local warming
0%
House warming
0%
Global warming
0%
Country warming

.......... is a farming system with minimal or no use of chemicals such as fertilizers, herbicides, pesticides.

0%
Subsistence farming
0%
Ley farming
0%
Organic farming
0%
Industrial farming

Destruction of ozone can cause

0%
Skin cancer
0%
Cataract
0%
Hinder growth of plant
0%
All of these

Water pollution can be identified by testing its

0%
PH level
0%
Biological Oxygen Demand (BOD)
0%
Both a and b
0%
None of these

Full form of CEPHRI.

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Centre for Environmental and Personal Health Research Institute
0%
Central for Engineering and Public Health Report Institute
0%
Central Environmental and Public Health Engineering Research Institute
0%
None of these

The process of accumulating higher and higher amounts of a toxic material such as PCBs within the body of any animal is called

0%
Bioaccumulation
0%
Biological amplification
0%
Biological half-life
0%
None of the above

Which of the following falls under the category of e-waste?

0%
Mobile phone
0%
Oil tanks
0%
Chemical equipment
0%
None of the above

What is the toxic substance contained by typical electronic waste?

0%
PCBs
0%
Dioxin
0%
Pesticide like compounds
0%
Heavy metals

The garbage or trash collected regularly is known as

0%
Domestic waste
0%
Municipal waste
0%
Agricultural waste
0%
Radioactive waste

Euro IV norm was implemented to most polluted cities of India in

0%
1 April 2005
0%
1 April 2000
0%
1 April 2007
0%
1 April 2010

Bharat stage emission standards is instituted in India to regulate

0%
Air pollution
0%
Soil pollution
0%
Water pollution
0%
None of the above

E-waste contains hazardous substances that are harmful to the environment and human health if not properly treated or disposed of, therefore they must be handled with care.
What are the health hazards which can be caused by e-waste?

0%
Brain
0%
Lung cancer
0%
DNA damage
0%
All of the above

CBSE Questions for Class 12 Medical Biology Environmental Issues Quiz 5 - MCQExams.com

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Practice Class 12 Medical Biology Quiz Questions and Answers

CBSE Questions for Class 12 Medical Biology Environmental Issues Quiz 5 - MCQExams.com

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Practice Class 12 Medical Biology Quiz Questions and Answers

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