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100 questions in this collection · Page 5 of 10
Question 41 of 100
📘 CLASS XII
Environmental Issues
Consider the following statements regarding the Arcata Marsh project in California:
I. It was an integrated wastewater treatment process developed in collaboration with Stanford University. II. The first stage of treatment involves conventional sedimentation, filtering, and chlorine treatment. III. After the first stage, dangerous dissolved heavy metals are still present in the water. IV. The second stage consists of six connected marshes over 60 hectares of marshland seeded with appropriate plants, algae, fungi, and bacteria.
Which of the statements given above are correct?
The Arcata Marsh project was developed jointly by the town of Arcata and biologists from Humboldt State University, not Stanford University. Conventional treatment is followed by natural purification through six connected marshes.
Question 42 of 100
📘 CLASS XII
Environmental Issues
Regarding solid wastes and their categorization, consider the following statements:
I. Solid wastes are categorized into three types: biodegradable, recyclable, and non-biodegradable. II. Recyclable materials should be sorted and separated out; kabadiwallahs and rag-pickers play a major role in this. III. Biodegradable materials can be put into deep pits in the ground for natural breakdown. IV. The non-biodegradable waste is easily broken down by burying it in agricultural fields to act as fertilizer.
Which of the statements given above are correct?
Solid waste is categorized into biodegradable, recyclable and non-biodegradable components. Rag-pickers and kabadiwallahs help recycle useful materials, while biodegradable waste can be composted. Non-biodegradable waste cannot naturally decompose in soil and should never be buried as fertilizer.
Question 43 of 100
📘 CLASS XII
Environmental Issues
With reference to municipal solid waste and sanitary landfills, read the following statements:
I. Sanitary landfills were adopted as a substitute for open-burning dumps. II. In a landfill, wastes are compacted in a trench and covered with dirt daily. III. There is a serious danger of seepage of chemicals from landfills polluting the underground water resources. IV. Burning completely reduces the volume of all types of waste to zero ash.
Which of the statements given above are correct?
Statements I, II and III are correct. Sanitary landfills replaced open-burning dumps, where waste is compacted and covered daily. Chemical seepage (leachate) may pollute groundwater. Statement IV is incorrect because burning only reduces the volume of waste and leaves non-combustible ash and residues.
Question 44 of 100
📘 CLASS XII
Environmental Issues
Read the following statements regarding Ahmed Khan's innovation in Bangalore:
I. Polyblend is a fine powder of recycled, modified plastic. II. Polyblend is mixed with bitumen to lay roads, which increases road life by a factor of three. III. Against the regular price of Rs 0.40 per kg, Ahmed Khan offered Rs 6 per kg to rag pickers for plastic film waste. IV. By the year 2002, more than 400 kms of road in Bangalore had already been laid using Polyblend.
Which of the statements given above are correct?
Statements I, II and III are correct. Polyblend is recycled modified plastic mixed with bitumen to improve road durability. Ahmed Khan encouraged plastic collection by offering Rs. 6 per kg. Statement IV is incorrect because by 2002, only about 40 km of roads had been laid using this technology, not 400 km.
Question 45 of 100
📘 CLASS XII
Environmental Issues
Consider the following statements about organic farming practiced by Ramesh Chandra Dagar:
I. He practiced integrated organic farming in Sonipat, Haryana. II. His farm includes bee-keeping, dairy management, water harvesting, composting, and agriculture in a mutually supportive chain. III. He uses chemical fertilizers in small, controlled doses to supplement cattle dung. IV. He created the Haryana Kisan Welfare Club, which now has a membership of 5,000 farmers.
Which of the statements given above are correct?
Statements I, II and IV are correct. Ramesh Chandra Dagar practices zero-waste integrated organic farming where compost and cattle dung eliminate the need for chemical fertilizers. Therefore, Statement III is incorrect.
Question 46 of 100
📘 CLASS XII
Environmental Issues
Read the following statements regarding the disposal of radioactive waste:
I. Radiation given off by nuclear waste causes mutations at a very high rate. II. At high doses, nuclear radiation is lethal, but at lower doses, it creates various disorders, mainly cancer. III. Nuclear waste is considered a highly potent pollutant. IV. The recommended method of disposal is storage in suitably shielded containers buried within rocks about 50 meters deep.
Which of the statements given above are correct?
Statements I, II and III are correct. Radioactive waste is highly hazardous and can cause mutations, cancer and death. Statement IV is incorrect because shielded radioactive waste containers are recommended to be buried about 500 metres deep inside rocks, not 50 metres.
Question 47 of 100
📘 CLASS XII
Environmental Issues
Consider the following statements regarding the Greenhouse Effect:
I. The greenhouse effect is a naturally occurring phenomenon responsible for heating the Earth's surface and atmosphere. II. Without this effect, the average temperature at the Earth's surface would be -18°C. III. Clouds and gases reflect about half of the incoming solar radiation and absorb the rest. IV. Almost half of the incoming solar radiation falls on the Earth's surface, heating it.
Which of the statements given above are correct?
Statements I, II and IV are correct. Without the greenhouse effect, Earth's average temperature would be about -18°C. Clouds and gases reflect only about one-fourth of incoming solar radiation, making Statement III incorrect.
Question 48 of 100
📘 CLASS XII
Environmental Issues
Read the following statements regarding Ozone in the atmosphere:
I. 'Bad' ozone is formed in the troposphere (lower atmosphere) and harms plants and animals. II. 'Good' ozone is found in the stratosphere (upper atmosphere) and acts as a shield absorbing UV radiation. III. Ozone gas in the stratosphere is continuously formed by the action of UV rays on molecular oxygen and also degraded into molecular oxygen. IV. The thickness of ozone is measured in terms of Dobson Units (DU).
Which of the statements given above are correct?
All four statements are correct. Tropospheric ozone is a pollutant, whereas stratospheric ozone protects life by absorbing harmful UV radiation. Ozone is continuously formed and degraded, and its thickness is measured in Dobson Units (DU).
Question 49 of 100
📘 CLASS XII
Environmental Issues
With reference to the chemical mechanism of Ozone Depletion, analyze the following statements:
I. CFCs discharged in the lower atmosphere move upward and reach the stratosphere. II. In the stratosphere, UV rays act on CFCs, releasing chlorine atoms. III. Chlorine atoms act merely as catalysts in degrading ozone, releasing molecular oxygen. IV. Chlorine atoms are consumed in the reaction, meaning CFCs have temporary effects.
Which of the statements given above are correct?
Statements I, II and III are correct. Chlorine atoms released from CFCs catalytically destroy ozone molecules and are not consumed in the reaction. Hence Statement IV is incorrect.
Question 50 of 100
📘 CLASS XII
Environmental Issues
Read the following statements about the Ozone Hole:
I. Depletion of ozone is particularly marked over the equatorial region. II. The ozone hole over Antarctica develops each year between late August and early October. III. It represents a large area of a significantly thinned ozone layer. IV. The depletion of ozone leads to an increased penetration of UV-B radiation to the Earth's surface.
Which of the statements given above are correct?
Statements II, III and IV are correct. Ozone depletion is particularly severe over Antarctica, not the equatorial region. The ozone hole forms annually between late August and early October and allows greater penetration of harmful UV-B radiation.