Smog is ______________________? A. Nothing but black smokeB. A combination of smoke and fog C. A liquid particle resulting from vapor condensation D. A solid particle e.g. fly-ash

Threshold limit value (TLV) i.e., the maximum permissible safe limit of phosgene gas which Hitler used to use to kill his enemies in ‘gas chamber’ is about ______________ ppm? A. < 1 B. 10-100 C. 100-200 D. 100-1000

For existence of aquatic life in water, the dissolved oxygen content in it, should not be less than ______________ ppm? A. 10000B. 5 C. 500 D. 1000

Very small amount of air pollutants are present in stratosphere also; though most of the atmospheric pollutants are present in the troposphere. Which of the following atmospheric pollutants does not cause the ozone layer depletion in atmosphere at tremendous rate…

The term Biological Oxygen Demand (BOD) is used in relation to ______________________? A. Potable water B. Cooling water C. Distilled waterD. Industrial effluents

The upper layer of atmosphere is called the ____________________? A. Stratosphere B. Troposphere C. Ionosphere D. None of these

CFC (chloro fluoro carbon) is very highly reactive in causing depletion of ozone layer in the atmosphere. Each atom of chlorine liberated from CFC is capable of decomposing ________________ molecules of ozone? A. 102B. 105 C. 109 D. 1015

The average thickness of ozone layer in stratosphere is about _______________ dobson unit (DU)? A. 20B. 230 C. 750 D. 1500

Noise level audible to audience sitting in the 5th row from the stage during a large orchestra show corresponds to about _______________ decibels? A. 105B. 135 C. 160 D. 185

Disinfection of water is done to remove ______________________? A. Color B. Bad taste C. Foul odourD. Bacteria