Artificial way of causing rainfall to reduce air pollution makes use of
- A.silver iodide and potassium iodide
- B.silver nitrate and potassium iodide
- C.silver iodide and potassium nitrate
- D.silver nitrate and potassium chloride
Correct answer
Explanation
The correct answer is A, silver iodide and potassium iodide. These salts are the usual seeding agents in cloud seeding, the artificial way to make rain.
Cloud seeding sprays tiny particles into clouds that already hold moisture, from aircraft, rockets or ground generators. Silver iodide works well because its crystal structure is very close to that of ice, so supercooled water droplets freeze onto it and grow into ice crystals heavy enough to fall as rain or snow. Potassium iodide is often mixed in to help silver iodide dissolve and disperse in the seeding solution. Dry ice and common salt are other agents. Rain washes dust and other particles out of the air, which is why cloud seeding has been tried as an emergency measure against smog, including trials over Delhi.
B is wrong because silver nitrate is used in photography and indelible ink, not as a seeding agent. C is wrong because potassium nitrate is a fertiliser and an ingredient of gunpowder. D is wrong because neither silver nitrate nor potassium chloride is a standard seeding agent.
Exam tip: cloud seeding agents: silver iodide, potassium iodide, dry ice and common salt.
Practice Questions
View allWhich of the following is/are renewable source(s) of energy? 1. Fossil fuel 2. Biofuel 3. Uranium 4. Hydropower Select the correct answer using the code given below.
- A.2 only
- B.3 and 4
- C.1 and 3
- D.2 and 4
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Biofuel and hydropower are renewable because nature replaces them within a human lifetime, while fossil fuels and uranium are not.
Read the full explanation →Which one of the following is NOT decomposed by bacterial action ?
- A.Vegetable remains
- B.Plastic materials
- C.Animal carcasses
- D.Wastes of flowers
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Ordinary plastics are non-biodegradable, so bacteria and fungi cannot break them down in any useful length of time. Most plastics, such as polyethylene, polypropylene and PVC, are long synthetic polymers made from petroleum.
Read the full explanation →According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions?
- A.Locomotives using fossil fuels
- B.Ships using fossil fuels
- C.Extraction of metals from ores
- D.Power plants using fossil fuels
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The EPA names the burning of fossil fuels by power plants and other industrial facilities as the largest source of sulphur dioxide.
Read the full explanation →Free swimming macroscopic animals in an aquatic environment are referred to as
- A.Plankton
- B.Periphyton
- C.Benthos
- D.Nekton
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Nekton are animals large enough to be seen with the naked eye that swim actively and can move against water currents.
Read the full explanation →As per the Solid Waste Management Rules, 2016 in India, which one of the following statements is correct?
- A.Waste generator has to segregate waste into five categories.
- B.The Rules are applicable to notified urban local bodies, notified towns and all industrial townships only.
- C.The Rules provide for exact and elaborate criteria for the identification of sites for landfills and waste processing facilities.
- D.It is mandatory on the part of waste generator that the waste generated in one district cannot be moved to another district.
Show answer
The 2016 Rules set out detailed criteria for choosing sites for landfills and waste processing facilities. The Solid Waste Management Rules, 2016, framed under the Environment (Protection) Act, 1986, replaced the Municipal Solid Wastes Rules of 2000.
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