Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by Neither A nor B Both A & B Photosynthetic action of algae Natural aeration of water stream TRUE ANSWER : ? YOUR ANSWER : ?
The major reason of hydrodynamic noise (i.e., noise resulting from liquid flow) is Boundary layer separation Fluctuation in liquid flow Pipe vibrations Cavitation TRUE ANSWER : ? YOUR ANSWER : ?
The biological decomposition of organic substances in wastes controlled conditions is called Biological oxidation Incineration None of these Composting TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following is an adsorbant for removal of nitrogen oxides from gas/air? Silica gel Active carbon Pulverised limestone Bog iron (iron oxide) TRUE ANSWER : ? YOUR ANSWER : ?
Biological oxidation ponds remove organic matters present in the polluted water by Aerobic oxidation Neither A nor B Both A & B Using the activities of bacteria and other micro organisms TRUE ANSWER : ? YOUR ANSWER : ?
Presence of non-biodegradable substances, like alkyl benzene sulphonate (ABS) from the detergents in polluted water stream causes Depletion of dissolved oxygen Persistent foam Explosion hazards Fire hazards TRUE ANSWER : ? YOUR ANSWER : ?
Fluorosis (a bone disease) is caused by the presence of high concentration of __________ in atmospheric air. Nitrogen dioxide Hydrocarbons Hydrogen sulphides Hydrogen flouride TRUE ANSWER : ? YOUR ANSWER : ?
Presence of __________ in water stream are deleterious to aquatic life. Soluble and toxic organics All of these Suspended solids Heavy metals and cynides TRUE ANSWER : ? YOUR ANSWER : ?
5-200 μm size particles are called Colloids or aerosols Powder Smoke Dust TRUE ANSWER : ? YOUR ANSWER : ?
The progressive warming up of the earth's surface is mainly due to the Thickening of ozone layer De-forestation Automobile exhaust Blanketing effect of CO₂ in the atmosphere TRUE ANSWER : ? YOUR ANSWER : ?