Biochemical Oxygen Demand (BOD) in river water:
1. | remains unchanged when algal bloom occurs |
2. | has no relationship with the concentration of oxygen in the water |
3. | gives a measure of Salmonella in the water |
4. | increases, when sewage gets mixed with river water |
Global agreement in specific control strategies to reduce the release of ozone-depleting substance was adopted by:
1. Rio de Janeiro Conference
2. The Montreal Protocol
3. The Kyoto Protocol
4. The Vienna Convention
A lake near a village suffered heavy mortality of fish within a few days. Consider the following reasons for this:
1. | Lots of urea and phosphate fertilizer were used in the crops in the vicinity. |
2. | The area was sprayed with DDT by an aircraft. |
3. | The lake water turned green and stinky |
4. | Phytoplankton populations in the lake declined initially, thereby, greatly reducing photosynthesis. |
Which two of the above were the main causes of fish mortality in the lake?
1. 2, 3
2. 3, 4
3. 1, 3
4. 1, 2
1. 2.5 or less
2. 1.5 or less
3. 1.0 or less
4. 5.2 or 2.5
Which one of the following statements is correct?
1. | Extensive use of chemical fertilizers may lead to eutrophication of nearby water bodies |
2. | Both Azotobacter and Rhizobium in root nodules of plants |
3. | Cyanobacteria such as Anabaena and Nostoc are important mobilizers of phosphates and potassium for plant nutrition in the soil |
4. | At present it is not possible to grow maize without chemical fertilizers |
1. Jatropha
2. Azadirachta
3. Musa
4. Aegilops
In which one of the following the BOD (Biochemical Oxygen Demand) of sewage (S), distillery effluent (DE), paper mill effluent (PE) and sugar mill effluent (SE) have been arranged in ascending order?
1. SE < S < PE < DE
2. SE < PE < S <DE
3. PE < S < SE < DE
4. S < DE < PE <SE
In a coal fired power plant, electrostatic precipitators are installed to control the emission of:
1.
2.
3. SPM
4. CO
1. CFCs 14%, CH4 20%
2. CO2 40%, CFCs 30%
3. N2O 6%, CO2 86%
4. CH4 20%, N2O 18%
Which one of the following is not a bioindicator of water pollution?
1. Sludge-worms
2. Blood-worms
3. Stone files
4. Sewage fungus