A. Coal
B. Silica
C. Iron
D. None of these
A. By reaction of hydrocarbon & nitric oxide in presence of sunlight
B. Appears only on sunny days
C. Is harmful for crops and trees also besides causing eye irritation & asthma
D. All A., B. & C.
A. Dissolved oxygen content
B. Biological oxygen demand
C. Vapor pressure
D. All A., B. and C.
A. 10 to 20
B. 100 to 200
C. 1500 to 2500
D. 4000 to 5000
A. Ozone
B. Photochemical smog
C. Sulphur dioxide
D. All A., B. & C.
A. Chemical coagulation
B. Floatation & skimming
C. Centrifugation
D. Ultra filtration
A. Cancer
B. Asthma
C. Silicosis
D. Fluorosis (bone disease)