Tag: physics

In the given options,other than nitrogen gas,rest all the gases has the capability of trapping the heat rays reflecting from the earth.(they trap the heat rays because they have certain properties which are either enhanced or reduced due to heat)

1. Carbon dioxide 
   2. Methane 
   3. Nitrous oxide 

A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect on planets. The primary greenhouse gases in Earth's atmosphere are water vapour $(H _2O)$, carbon dioxide $(CO _2)$, methane $CH _4)$, nitrous oxide $(N _2O)$ and ozone $(O _3)$. Among the given gases, $CO _2$ is not present in very high quantity.

Scientists use these factors to calculate a gass global warming potential, which measures how much heat it absorbs per pound.

Process of warming of planet's surface and its lower atmosphere by the absorption of infrared radiations of long wavelength given out from the surface of a planet is known as green house effect.  In 1824, Joseph Fourier discovered the green house effect. The earth's transparent for the infrared radiations of short wavelengths coming from the sun. The high energy radiations such as X rays, gamma rays, UV rays are absorbed by the ozone layer while the low energy radiations namely infrared radiations of long wavelength and radio waves are reflected back into the space.

Since greenhouse gases trap heat rays (infrared rays) which due to irradiation keeps the earth warm.

Process of warming of planet's surface and its  lower atmosphere by the absorption of infrared radiations of long wavelength given out from the surface of a planet is known as green house effect. In 1824, Joseph Fourier discovered the green house effect.

They trap the heat rays because they have certain properties which are either enhanced or reduced due to heat.Capturing infrared rays is a characteristic properties of greenhouse gases.

The greenhouse effect itself occurs when short-wave solar radiation (which is not impeded by the greenhouse gases) heats the surface of the Earth, and the energy is radiated back through the Earth's atmosphere as heat, with a longer wavelength. In the wavelengths 5-30m a lot of this thermal radiation is absorbed by water vapour and carbon dioxide, which in turn radiate it, thus heating the atmosphere and land and ocean surface. This is natural and what keeps the Earth habitable.

Without the greenhouse effect overnight temperatures would plunge and the average surface temperature would be about minus 18C, about the same as on the moon, which lacks the shroud of our atmosphere.
Thus Option A is correct.

Methaneemitted from landfills, coal mines, oil/gas operations, and agricultural livestockaccounted for 10 percent of U.S. greenhouse gas emissions.