251.Which of the following is an adsorbent used for the removal of SO2 from gas/air?
Bog iron
Limestone powder or alkalised alumina
Silica gel
Active carbon
Correct answer: (B) Limestone powder or alkalised alumina
252.Which of the following is not a natural source of air pollution?
Volcanic eruptions and lightening discharges
Biological decay of vegetable matter
Photochemical oxidation of organic matter
None of these
Correct answer: (D) None of these
253.Which of the following is not a practical method of low level radioactive waste disposal?
Dilution with inert material
Discharging to atmosphere through tall stacks after dilution
Disposing off in rivers&oceans
Filling in steel crates and shooting it off out of earth's gravity
Correct answer: (D) Filling in steel crates and shooting it off out of earth's gravity
254.Which of the following is not a secondary air pollutant?
Ozone
Photochemical smog
Sulphur dioxide
All (A), (B)&(C)
Correct answer: (C) Sulphur dioxide
255.Which of the following is not a source of ozone emission in the atmosphere?
Refrigerators
Xerox machines
Dermatological photo-therapy equipments
High voltage electrical equipments
Correct answer: (A) Refrigerators
256.Which of the following is not a weightless pollutant?
SPM
Thermal pollution
Radioactive rays
Noise pollution
Correct answer: (A) SPM
257.Which of the following is the common pollutant emitted from metallurgical smelters, thermal power plant and cement plants?
NOx
Hg
SO2
F
Correct answer: (C)
SO2
258.Which of the following is the most active zone of atmosphere in which weathering events like rain, storm&lightning occur?
Thermosphere
Troposphere
Stratosphere
None of these
Correct answer: (B) Troposphere
259.Which of the following is the most detrimental for water used in high pressure boiler?
Silica
Turbidity
Phenol
Dissolved oxygen
Correct answer: (A) Silica
260.Which of the following is the most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted water stream?