UGC NET Questions (Paper – 1)

The greenhouse effect occurs when gases such as carbon dioxide,water vapour and methane absorb outgoing infrared radiation and re emit it toward the Earth’s surface. This process keeps the planet’s average temperature at a level suitable for life. The stem clearly describes this trapping and warming mechanism. Therefore the correct name is greenhouse effect.

Option A:
The albedo effect refers to the reflectivity of Earth’s surface and atmosphere,which determines how much solar radiation is reflected back into space. While it influences climate,it is distinct from the trapping of long wave radiation described in the question.

Option B:
The greenhouse effect involves the selective absorption and re emission of infrared radiation by greenhouse gases. This natural effect becomes enhanced when human activities increase greenhouse gas concentrations. Because the question focuses on this trapping process,greenhouse effect is the appropriate term.

Option C:
Ozone depletion is the thinning of the stratospheric ozone layer primarily due to chlorofluorocarbons. It increases the amount of harmful ultraviolet radiation reaching Earth,but it is not about trapping heat. Hence it is not the correct option.

Option D:
Acid rain describes precipitation with elevated acidity caused mainly by sulphur dioxide and nitrogen oxides dissolving in water. It leads to ecosystem damage and material corrosion but does not directly refer to atmospheric heat trapping.