Assertion (A): | There is always a sharp decline in dissolved oxygen downstream from the point of sewage discharge, which causes mortality of fish and other aquatic creatures |
Reason (R): | Micro-organisms involved in bio-degradation of organic matter in the receiving water body consume a lot of oxygen |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
1. | Kilobase | 2. | Dobson unit |
3. | Decibels | 4. | Decameter |
1. | The amount of some toxic substances of industrial wastewater increases in the organisms at successive trophic levels. |
2. | The micro-organisms involved in biodegradation of organic matter in a sewage-polluted water body consume aquatic organisms. |
3. | Algal blooms caused by excess of organic matter in water improve water quality and promote fisheries. |
4. | Water hyacinth grows abundantly in eutrophic water bodies and lead to an imbalance in the ecosystem dynamics of the water body. |
Given below are two statements:
I: | Electrostatic precipitator is most widely used in a thermal power plant. |
II: | Electrostatic precipitator in a thermal power plant removes ionising radiations. |
1. | Statement I is incorrect but Statement II is correct. |
2. | Both Statement I and Statement II are correct. |
3. | Both Statement I and Statement II are incorrect. |
4. | Statement I is correct but Statement II is incorrect. |
1. | Algal Bloom decreases fish mortality. |
2. | Eutrophication refers to increase in domestic sewage and waste water in lakes. |
3. | Biomagnification refers to increase in concentration of the toxicant at successive trophic levels. |
4. | Presence of large amounts of nutrients in water restricts 'Algal Bloom'. |
1. | Eutrophication | 2. | Humification |
3. | Mineralisation | 4. | Stratification |
1. | Amount of dissolved oxygen in the lake will decrease. |
2. | The lake will remain unaffected |
3. | Number of submerged aquatic plants in the lake will increase |
4. | Number of aquatic animals in the lake will increase. |
List-I | List-II | ||
(A) | Deforestation | (I) | Responsible for heating of Earth's surface and atmosphere |
(B) | Reforesation | (II) | Conversion of forested areas to non-forested areas |
(C) | Green-house effect | (III) | Natural ageing of lake by nutrient enrichment of its water |
(D) | Eutrophication | (IV) | Process of restoring a forest that once existed but was removed |
Options: | (A) | (B) | (C) | (D) |
1. | IV | III | II | I |
2. | I | II | III | IV |
3. | III | I | II | IV |
4. | II | IV | I | III |
A: | BOD is inversely related to dissolved oxygen |
B: | Low dissolved oxygen and high BOD lead to loss of aquatic life. |
C: | High BOD leads to high dissolved oxygen |
D: | Both BOD and dissolved oxygen are indicator of health of a water body |
E: | Both BOD and dissolved oxygen are affected by amount of organic matter in the water body. |
1. | (A), (B), (C), (E) only | 2. | (A), (B), (D), (E) only |
3. | (A), (B), (C), (D) only | 4. | (B), (C), (D), (E) only |
The device which can remove particulate matter present in the exhaust from a thermal power plant is :
1. Catalytic Convertor
2. STP
3. Incinerator
4. Electrostatic Precipitator