Q.1
TLV of aldrin in public water supply system is about __________ μg/litre.
Q.2
Threshold Limit Value (TLV) is the maximum allowable concentration (i.e. safe limit) of pollutants in air. Safe limit for SO₂ in air is __________ ppm.
Q.3
In sewage treatment, its sedimentation is speeded up by commonly adding
Q.4
Maximum allowable concentration of CO₂ in air for safe working is __________ ppm (parts per million).
Q.5
Out of the following, TLV of __________ is maximum (about 500 ppm).
Q.6
The lowest layer of atmosphere is known as the
Q.7
__________ is the process of killing organism in water.
Q.8
Maximum allowable noise exposure limits for a man working for 8 hours a day in a noisy chemical plant is about __________ decibels.
Q.9
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.
Q.10
In a sedimentation tank, the detention period for water ranges from __________ hours.
Q.11
In sewage treatment, the detention period allowed for oxidation ponds ranges from __________ weeks.
Q.12
Presence of high concentration of ozone and smog in atmospheric air causes the
Q.13
Presence of volatile compounds like gasoline, oil, alcohol, ether etc. in municipal sewers may cause
Q.14
Out of the following, TLV of __________ is the minimum (about 0.02 ppm).
Q.15
Limestone powder is injected during pulverised coal burning in boilers to __________ the flue gases.
Q.16
Sound produced by an automobile horn heard at a distance of 1.5 metres corresponds to about __________ decibels.
Q.17
Operating principle of cyclone separator is based on the action of __________ dust particles.
Q.18
Black smoke coming out of the chimney of a furnace is an indication of the use of __________ in the furnace.
Q.19
A standard test for determination of hardness in water is termed as __________ test.
Q.20
Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly __________ substances.
Q.21
Atmospheric pollution caused by the exhaust gas of supresonic transport air-crafts is mostly in the atmospheric region called
Q.22
Most of the bacteria in sewage are
Q.23
__________ content of the phosphate rock is the pollutant of primary interest in a phos-phatic fertiliser plant.
Q.24
Noise emitted by a ventilation fan at a distance of 3 metres is about __________ decibels.
Q.25
Noise level inside a jet air liner in normal flight is about __________ decibels.
Q.26
Which of the following is an adsorbant used for the removal of SO₂ from gas/air?
Q.27
Turbidity of water is an indication of the presence of
Q.28
Pick out the wrong statement.
Q.29
Noise level audible to audience sitting in the 5th row from the stage during a large orchestra show corresponds to about __________ decibels.
Q.30
Presence of iron and manganese in water causes
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