Tag: depletion of ozone layer

Questions Related to depletion of ozone layer

Gases responsible for green house effect are

  1. $CO _2$

  2. CFC

  3. $N _2O$

  4. All the above


Correct Option: D
Explanation:

A greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapour, carbon dioxide, methane, CFC's, nitrous oxide, and ozone.

So the correct answer is 'All the above'.

One GHG contributes $6\%$ to total global warming, other contributes to $20\%$; they are.

  1. $NO _2$ and $CO _2$

  2. $N _2O$ and CFCs

  3. CFCs and methane

  4. $N _2O$ and methane

  5. $CO _2$ and CFCs


Correct Option: D
Explanation:
The relative contribution of various greenhouse gases to total global warming are as follows:
Methane: 20%
CFCs(Chloro-fluoro-carbons): 14%
N$ _2$O: 6%
Carbon dioxide: 60%
So, the correct answer is 'Option D- N$ _2$O and methane'.

Greenhouse gases are

  1. $CO _2$ and $CH _4$

  2. $N _2O$ and CFCs

  3. Ozone

  4. All of the above


Correct Option: D
Explanation:

Carbon dioxide and methane are naturally occurring gases. Nitrous oxides are formed due to denitrification and combustion of the fossil fuels. CFCs are used as refrigerants and propellants. Ozone is formed as a secondary pollutant. All these are greenhouse gases because they show greenhouse effect by absorbing the the long-wavelength infra-red radiations coming from the earth's surface and preventing from leaving the atmosphere. This effect is responsible for maintaining the ambient temperature on the earth. Their  amounts have increased over the past years and this has adversely affected the global temperature by raiding it. This is called global warming and is responsible for climate change. 

Hence, the correct answer is 'All of the above'

Which one of the following statements is not correct?

  1. The greenhouse gases trap out the heal in infra-red radiation

  2. Natural gas supplies five percent f global energy needs

  3. One molecule of CFC can trap as many as $10,000$ molecules of $CO _2$

  4. The atmospheric life time to $CFCl _3$ is estimated at $75$ years


Correct Option: A

Green house gases are called as such because they.

  1. Prevent the escape of heat waves reradiated from the earth's surface

  2. Are produced in greenhouses

  3. Are used in warming plant growth chambers

  4. Help in maintaining atmospheric $O _2$ and $CO _2$ balance


Correct Option: A

Choose the correct answer form the alternatives given.
The second biggest greenhouse gas emitter (after the USA) in the world is:

  1. Russia

  2. Germany

  3. China

  4. Japan


Correct Option: C

Cyclic variations of CO2CO2 concentration in the atmosphere are due to changes in

  1. photosynthetic activity

  2. respiratory activity

  3. burning of fossil fuels

  4. action of infra-red rays


Correct Option: C
Explanation:

The burning of fossil fuels such as gasoline, coal, oil, natural gas in combustion reactions results in the production of carbon dioxide. There are cyclic variations of Carbon dioxide concentration in the atmosphere due to this reason. 

So, the correct optionos 'Burning of fossil fuels'.

Which one of the following is major given house gas?

  1. Freon

  2. $CO _2$

  3. CFC

  4. $NO _2$


Correct Option: B
Explanation:

greenhouse gases are those gases which absorb the heat or thermal infrared radiations of the sun and is responsible for an increase in the temperature of the earth's surface .there are several greenhouse gases that are produced either naturally or is being emitted in the atmosphere by a man-made source. The most abundant or major greenhouse gas is Carbon Dioxide.

so the correct answer is 'CO2'.

Increase in carbon dioxide in atmosphere is harmful because it

  1. traps heat

  2. causes respiratory disorders

  3. forms smog

  4. increases turbidity


Correct Option: A
Explanation:

Carbon dioxide is one of the most abundant and major greenhouse gas which entraps the heat and causes the rise in temperature of the earth surface hence is greatly responsible for global warming also.

so the correct answer is 'traps heat'.

Multiple Choice Questions
Which one is correct percentage of green house gases

  1. Methane - $20\%$, $N _2O $- $18\%$

  2. CFCs -$14\%$, Methane - $20\%$

  3. $CO _2$ - $40\%$, CFCs -$30\%$

  4. $N _2O$ - $6\%. $ $CO _2$ - $86\%$


Correct Option: B
Explanation:

Relative concentration of various greenhouse gases in the atmosphere is as: CO$ _2$ (60%), CH$ _4$ (20%), CFCs (14%) and N$ _2$O (6%).

So, the correct answer is CFCs-14%, Methane 20%.