CBSE
Multiple Choice QuestionsWhich one of the following is mainly responsible for depletion of ozone layer?
Methane
Carbon dioxide
Water
Chlorofluorocarbons
Photochemical smog is due to the presence of:
Oxides of sulphur.
Oxides of nitrogen.
Oxides of carbon.
Chlorofluoro carbons.
In which part of the atmosphere, does the freon remain unchanged?
Stratosphere
Troposphere
Mesosphere
Thermosphere
Which of the following has highest concentration of PAN?
Smoke
Ozone
Photochemical smog
Reducing smog
Which of the following is secondary pollutant?
CO2
N2O
PAN
SO2
Alum is a water purifier, because it :
coagulates the impurities
softens hard water
gives taste
destroys the pathogenic bacteria
Ozone layer is being depleted. This is due to :
NO (nitric oxide) emission from supersonic jets
chlorofluoro carbon used as aerosols
Both (a) and (b)
None of the above
Use of chlorofluorocarbons is not encouraged because :
they are harmful to the eyes of peoplethat use it
they damage the refrigerators and air conditioners
they eat away the ozone in the atmosphere
they destroy the oxygen layer
Which one of the following elements, is a component of a compound essential for photosynthesis ?
Iron
Calcium
Barium
Magnesium
Photochemical oxidants, i.e. PAN or PBN are formed by:
action of nitrogen oxides on hydrocarbons in presence of sunlight
action of CO2 on hydrocarbons in presence of sunlight
action of hydrogen sulphide on hydrocarbon in presence of sunlight
None of the above
