Question

Greenhouse gases include
A. $CO_2$, CFC, $CH_4$ and $N_{2}O$
B. $CO_2$, $O_2$, $N_2$ and $NH_3$
C. $CH_4$, $N_2$, $CO_2$ and $NH_3$
D. CFC, $CO_2$, $NH_3$ and $N_2$

Answer 1

Hint: Greenhouse effect is a natural process that occurs when gases in the earth’s atmosphere trap sunlight. These gases absorb and emit energy within infrared range. It causes the heating of the earth surface.

Complete Answer:
- The light energy emitted by the sun warms the earth surface. Much of the energy is absorbed by certain gaseous molecules which emit radiations in the form of heat. These gases are called the greenhouse gases. The gases which emit infrared radiation are
- Carbon dioxide which is obtained by burning fossil fuel.
- Chlorofluorocarbon ( emitted by jet engines)
- Methane or the marsh gas obtained by inorganic decomposition of plant waste.
- Nitrous oxide obtained from agricultural and industrial activity.
- These gases are also responsible for depleting the ozone layer which protects the earth from harmful UV rays.
- In the atmosphere nitrogen has the major composition around 78% followed by oxygen which is 21%. These gases are essential for supporting life on earth.
- Ammonia is a volatile gas emitted by animal waste, fertilizers, etc. It is the major gaseous pollutant which causes eutrophication and acidification.

Thus the correct answer is (A). Major Greenhouse gases are carbon dioxide, chlorofluorocarbon, methane and nitrous oxide.

Note: Earth’s natural greenhouse effect is very important for supporting life. Human activities like burning of fossil fuels and cutting of forests have increased the greenhouse effect. As a consequence of which global warming is increasing rampantly.