Discuss briefly the following: A. Greenhouse gases B. Catalytic converter C. Ultraviolet B

A.>Greenhouse gases

i.>The gases present in the atmosphere that trap the sun’s heat and are responsible for the heating of earth’s atmosphere are called greenhouse gases. E.g. Methane, CO2 etc.

ii.>These gases are responsible for the greenhouse effect. The sunlight contains infrared radiations which are responsible for the heating. Earth reflects the radiations back into the atmosphere but not all the radiations escapes as some part of it is absorbed by the greenhouse gases.

iii.>This helps in maintaining a hospitable temperature of the earth’s surface (average temperature being 15⁰C) as it provides balance in the temperature during day and night. 

iv.>But recently due to excessive pollution and releasing of CO2 and other greenhouse gases in the atmosphere, more heat is being trapped in the atmosphere leading to an overall increase in the temperature of the Earth known as Global Warming.

B.>Catalytic converter

i.>Catalytic converters are devices fitted in automobiles to reduce the emission of harmful and poisonous gases.

ii.>They contain metals such as platinum, palladium and rhodium as catalysts that convert the unburnt hydrocarbons, carbon monoxide(CO) and nitric oxide passing through them into less harmful Carbon dioxide(CO2), water and nitrogen respectively.

iii.>Automobiles fitted with catalytic converters should use unleaded petrol because lead in petrol inactivates the catalysts.

C.>Ultraviolet B

i.>Ultraviolet B has shorter wavelength than the visible light and is extremely harmful for humans. 

ii.>UV-B penetrates deep into the skin and can cause mutations in the exposed cells.

iii.>It causes aging of skin cells and various types of skin cancers.

iv.>It can also cause inflammation in cornea called snow-blindness, cataract etc. Prolonged exposure is extremely harmful and can leave permanent damage to the cornea.