Question

Carbon dioxide is called a greenhouse gas because it is
A) Used in greenhouse to increase plant growth
B) Transparent to heat but traps sunlight
C) Transparent to sunlight but traps heat
D) Transparent to both sunlight and heat

Answer 1

Hint:Carbon dioxide is a colourless odourless, non-inflammable gas that is present in the atmosphere at very low levels. It is given out by humans through the process of respiration and taken up by plants for photosynthesis.

Complete answer:
The atmosphere of Earth consists of two major gases- nitrogen which comprises 78% and oxygen which comprises 21% and few other gases in trace amounts among which one is carbon dioxide. Greenhouse gases are those that are capable of trapping the infrared radiation which is emitted from the earth’s surface back to the earth’s surface causing a significant rise in temperature of the earth; which is known as global warming. The well known greenhouse gases are methane, carbon dioxide, nitrous oxide and water vapour. Carbon dioxide is known as a greenhouse gas because though it is transparent to sunlight, it traps heat and contributes to the overall increase of earth’s temperature.

Hence the correct option is (C) Transparent to sunlight but traps heat.

Note: Greenhouse gases are causing global warming that is not only changing the climate of the earth but also having adverse effects on the environments and the different life forms. It is causing an increase in sea level due to the melting of glaciers, change in precipitation pattern, expansion of deserts as well as extinction of many species of plants and animals.