Q1. Which of the following is a major cause of thermal pollution in water bodies?
- Discharge of treated sewage
- Discharge of heated water from power plants
- Agricultural runoff
- Oil spillage
Correct Option: 2. Discharge of heated water from power plants
Explanation: Power plants often use water as a coolant and discharge the heated water back into rivers or lakes, raising the water temperature. This change disrupts aquatic ecosystems.
Q2. Which of the following effects is NOT caused by warm water from thermal pollution?
- Increase in dissolved oxygen
- Decreased biodiversity
- Algae blooms
- Increased metabolic rate of aquatic animals
Correct Option: 1. Increase in dissolved oxygen
Explanation: Warm water decreases the level of dissolved oxygen (DO), which negatively affects aquatic life. Thus, the increase in DO is not an effect—it’s the opposite.
Q3. A strip of vegetation along the shoreline helps prevent thermal pollution by:
- Increasing the flow of water
- Filtering chemical waste
- Providing shade and reducing water temperature rise
- Absorbing noise from factories
Correct Option: 3. Providing shade and reducing water temperature rise
Explanation: Vegetation along shorelines helps shade the water, preventing sunlight from directly heating it, which reduces thermal pollution.
Q4. Which of the following is a direct source of soil pollution?
- Earthquakes
- Deforestation
- Pesticide use
- Wind erosion
Correct Option: 3. Pesticide use
Explanation: Pesticides are directly sprayed onto the soil in agriculture, introducing harmful chemicals that affect soil organisms and reduce fertility.
Q5. Which of the following best describes “Skyglow” in the context of light pollution?
- The reflection of sunlight from the Moon
- The scattering of artificial light in the night sky, reducing visibility of stars
- The glow of stars in the absence of pollution
- The emission of light by bioluminescent organisms
Correct Option: 2. The scattering of artificial light in the night sky, reducing visibility of stars
Explanation: Skyglow is a major component of light pollution, caused by the scattering of artificial lights (street lamps, buildings, etc.) into the atmosphere. It brightens the night sky, making it difficult to see stars and other celestial objects. This affects astronomy and disrupts nocturnal ecosystems.