Q. Dose of chlorine for disinfection of water is about __________ mg/litre of water.

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Q. Foul odour and bad taste of water is removed by treating with

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Q. Presence of __________ in water stream are deleterious to aquatic life.

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Q. Acute danger to human life (i.e. death) exists, if the concentration of CO₂ in atmospheric air exceeds __________ percent (by volume).

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Q. Methyl iso-cynate (MIC) gas (TLV <1 ppm), which caused Bhopal gas tragedy in 1984 falls under the category of __________ toxic gas.

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Q. Noise level heard inside a bus in busy city traffic or inside a sub-way train corresponds to about __________ decibels.

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Q. Workers working in __________ industry are most prone to white lung cancer.

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Q. A standard test for determination of hardness in water is termed as __________ test.

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Q. TLV of lead for public sewer/waste water is about __________ ppm.

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Q. Presence of nitrates in water in excess of 50 ppm causes

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Q. In sewage treatment, the detention period allowed for oxidation ponds ranges from __________ weeks.

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Q. The maximum permissible noise level to which a man working in a chemical plant can be exposed for eight hours per day is about __________ decibels.

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Q. The most commonly used chemical coagulant in water treatment is

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Q. The biological decomposition of organic substances in wastes controlled conditions is called

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Q. Lung cancer & DNA breakage are the major ill effects of excessive ozone exposure to human beings. Ozone layer depletion in the atmosphere is mainly caused by the presence of

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Q. Smog is not formed due to the presence of __________ in the atmosphere.

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Q. Pick out the correct statement.

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Q. Which of the following is not a source of ozone emission in the atmosphere ?

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Q. Oceans act as sinks for atmospheric gases including carbon dioxide whose concentration in the atmosphere is increased by the

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Q. Pick out the correct statement.

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