5-200 μm size particles are called (A) Colloids or aerosols (B) Powder (C) Dust (D) Smoke

5-200 μm size particles are called
(A) Colloids or aerosols
(B) Powder
(C) Dust
(D) Smoke
by

1 Answer

Answer :

(A) Colloids or aerosols
by

Related questions

Carbonaceous particles having size less than 1 μm are called (A) Grit (B) Aggregates (C) Aerosols (D) Smoke

Description : Carbonaceous particles having size less than 1 μm are called (A) Grit (B) Aggregates (C) Aerosols (D) Smoke

Last Answer : (D) Smoke

Particles having diameter greater than 75 μm (micrometer = 10 -6 mm) are called (A) Grit (B) Dust (C) Powder (D) Smoke

Description : Particles having diameter greater than 75 μm (micrometer = 10 -6 mm) are called (A) Grit (B) Dust (C) Powder (D) Smoke

Last Answer : (A) Grit

80% less than 200 mesh size particles are called (A) Smoke (B) Powder (C) Grit (D) Aggregates

Description : 80% less than 200 mesh size particles are called (A) Smoke (B) Powder (C) Grit (D) Aggregates

Last Answer : (B) Powder

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below : Δ P/L = 375 × 10 3 VOM + 10.94 × 10 6 V2 OM (SI units) If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is (A) 12 mm/s (B) 16 mm/s (C) 24 mm/s (D) 28 mm/s

Description : A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle ... fluidisation velocity, VOM is (A) 12 mm/s (B) 16 mm/s (C) 24 mm/s (D) 28 mm/s

Last Answer : (B) 16 mm/s

A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun's equation for the above fluid-particle system (in SI units) is given below: Δ P/L = 375 × 10 3 VOM + 10.94 × 10 6 V2 OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed? (A) 0.2 (B) 0.5 (C) 0.7 (D) 0.8

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Last Answer : (C) 0.7

The energy required per unit mass to grind limestone particles of very large size to 100 μm is 12.7 kWh/ton. An estimate (using Bond's law) of the energy to grind the particles from a very large size to 50 μm is (A) 6.35 kWh/ton (B) 9.0 kWh/ton (C) 18 kWh/ton (D) 25.4 kWh/ton

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Particulates (< 1μm size) remaining suspended in air indefinitely and transported by wind currents are called (A) Fumes (B) Mists (C) Smoke (D) Aerosols

Description : Particulates (< 1μm size) remaining suspended in air indefinitely and transported by wind currents are called (A) Fumes (B) Mists (C) Smoke (D) Aerosols

Last Answer : (D) Aerosols

Particulates (< 1 µm size) remaining suspended in air indefinitely and transported by wind currents are called (1) Mists (2) Fumes (3) Aerosols (4) Smoke

Description : Particulates (< 1 µm size) remaining suspended in air indefinitely and transported by wind currents are called (1) Mists (2) Fumes (3) Aerosols (4) Smoke

Last Answer : Aerosols

A 30% (by volume) suspension of spherical sand particles in a viscous oil has a hindered settling velocity of 4.44 μm/s. If the Richardson Zaki hindered settling index is 4.5, then the terminal velocity of a sand grain is (A) 0.90 μm/s (B) 1 μm/s (C) 22.1 μm/s (D) 0.02 μm/s

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Last Answer : (B) 1 μm/s

Among the colloids cheese (C), milk (M) and smoke (S), the correct combination of the dispered phase and dispersion medium, respectively is :

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According to CPCB, Which size of dust particles in air pollution are harmful to human beings

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Sulfuric acid aerosols from the eruption of Mt. Pinatubo reduced the rate of global warming last year. They also contributed to the record size of: w) acid rainfalls in Europe x) the anchovy catch off Peru y) the ozone hole over Antarctica z) fish kills in the Amazon River

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The most suitable equipment for the transportation of 200 mesh size particles is a (A) Bucket elevator (B) Pneumatic conveyor (C) Screw conveyor (D) Belt conveyor

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Particulate' air pollutants are finely divided solids and liquids. Which of the following is not a ‘particulate’? (A) Dust & mists(B) Smoke & fumes(C) Photochemical smog & soot(D) None of these

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My body gets darker in some places in winter . In summer, when you come in contact with powder or husk and dust and sand, you actually get redness on your face, sneezing, itching of nose, in winter, when you come in contact with them, you actually get redness on your face.

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Last Answer : You have cold and skin allergies. Which is why these things are happening. Anyway, let's talk about cold allergies first. Don't let it get cold. Eat it mixed with hot water. Keep in mind that it ... skin wet. Apply Vaseline or olive oil. Give Dove Milk soap to your face every day. Drink more water.

The most efficient equipment for the removal of sub-micronic dust particles from blast furnace gas is the (A) Venturi atomiser (B) Gravity settling chamber (C) Electro-static precipitator (D) Cyclone separator

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Operating principle of cyclone separator is based on the action of __________ dust particles. (A) Diffusion of (B) Centrifugal force on (C) Gravitational force on (D) Electrostatic force on

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Which of the following dust collection equipments is the least efficient (for sub-micronic particles)? (A) Dust catcher (gravity type) (B) Cyclone separator (C) Bag filter (D) Hollow wet scrubber

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Oxygen molecule absorption peaks to electromagnetic wave are at what wavelengths? A. 1.35 cm and 1.7 mm B. 5 mm and 2.5 mm C. 5 cm and 2.5 cm D. 1.35 mm and 1.7 μm

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Calculate the static deflection in μm of transverse vibrations if the frequency is 200Hz. A. 6.21 B. 0.621 C. 62.1 D. 0.006

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Calculate the static deflection in μm of transverse vibrations if the frequency is 200Hz. a) 6 b) 0.6 c) 60 d) 0.006

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The length of each mitochondrion is about (A) 1.0 μm (B) 0.2 μm (C) 10 μm (D) 2.0 μm

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Which of the following colour is least scattered by fog, dust or smoke : A. Violet B. Blue C. Red D. Yellow

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The open "Sigrees" or coal stoves often require fanning to sustain burning because of (1) tendency of carbon dioxide to form a layer along with dust smoke (2) lack of oxygen in the surroundings of sigrees (3) accumulation of smoke and dust over the sigrees (4) interrupted release of moisture from the material

Description : The open "Sigrees" or coal stoves often require fanning to sustain burning because of (1) tendency of carbon dioxide to form a layer along with dust smoke (2) lack of oxygen in the ... 3) accumulation of smoke and dust over the sigrees (4) interrupted release of moisture from the material

Last Answer : tendency of carbon dioxide to form a layer along with dust smoke

Natural sources of air pollution are (1) Forest fires (2) Volcanic eruptions (3) Dust storm (4) Smoke from burning dry leaves

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Last Answer : Volcanic eruptions

The property of the bearing material to allow the dust and abrasive particles to get absorbed on the surface of the lining is called (A) Embeddability (B) Conformability (C) Viscosity (D) Endurance limit stress

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Dust content in raw blast furnace gas is about __________ gm/Nm3 ; hence it is cleaned to the dust level of about < 10 mg /Nm3 before use. (A) 15-30 (B) 1-2 (C) 70-100 (D) 150-200

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Last Answer : (A) 15-30

The sun appears red at sunrise and sunset while it appears white at noon because of _____ A. Refraction B. It is cooler at sunrise and at sunset C. Diffraction leading to red end of the spectrum reaching the earth D. Scattering of light due to dust particles and air molecules

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Last Answer : ANSWER: D

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Description : Airmass near to the earth's surface is warmer because it – (1) radiates heat (2) contains dust particles (3) is warmed by terrestrial radiation (4) is far from the sun

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Which of the following represents the accepted method of cleaning dust and foreign particles from electrical equipment while limiting damage to electric components? A. Carefully wiping off the components with a soft cotton rag. B. Blowing a high velocity stream of compressed air rapidly across the components. C. Using a vacuum cleaner to remove debris from the components. D. Using carbon tetrachloride as a cleaning solvent to clean the components.

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Last Answer : Answer: C

A pulsar is a rapidly spinning neutron star which emits: A. A blinding light when it aligns with the planets B. Radio waves detectable from Earth (Answer) C. A gravitational pull which attracts high energy dust particles D. Enough energy to power itself indefinitely

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Last Answer : B. Radio waves detectable from Earth (Answer)

The sun appears red at sunrise and sunset while it appears white at noon, because A. Of refraction B. It is cooler at sunrise and at sunset C. Of diffraction leading to red end of the spectrum reaching the earth. D. Of Scattering of light due to dust particles and air molecules?

Description : The sun appears red at sunrise and sunset while it appears white at noon, because A. Of refraction B. It is cooler at sunrise and at sunset C. Of diffraction leading to red end of the spectrum reaching the earth. D. Of Scattering of light due to dust particles and air molecules?

Last Answer : C. Of diffraction leading to red end of the spectrum reaching the earth.

The Symbolic meaning of Dust of Snow is-(a) Particles of snow (b) Cool weather (c) White mountains (d) Healing power of nature

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Suppose a teacher has short height. It creates an obstacle in utilizing the black-board in a justifiable manner. Therefore, the students cannot follow the lessons inspite of utmost care taken by the teacher. In such a condition what would you like to suggest him? Options: A) Good! Atleast you can save your labour and clothes from dust particles B) You suggest him to make a temporary platform of bricks with the help of students C) You suggest him to make a complaint with the principal D) Collect donations from his student to reconstruct the black-board

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Last Answer : You suggest him to make a temporary platform of bricks with the help of students

Airmass near to the earth’s surface is warmer because it (1) radiates heat (2) contains dust particles (3) is warmed by terrestrial radiation (4) is far from the sun

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Last Answer : is warmed by terrestrial radiation

Sooty and sulphurous smog formed due to combustion of fossil fuels particularly in winter, continues throughout the day and night. When the moist atmospheric air's water vapor condenses on the solid particles of smoke thereby forming smog (smoke + fog), it causes (A) Poor visibility due to sky darkening (B) Irritation in eyes (C) Respiratory trouble (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in (A) Coagulation and flocculation of colloids (B) Oxidation of carbonaceous matter to CO2 (C) Nitrification or oxidation of ammonia derived from breakdown of nitrogenous organic matter to the nitrite and eventually to the nitrate (D) All (A), (B) and (C)

Description : Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in (A) Coagulation and flocculation of colloids (B) Oxidation of carbonaceous matter to CO2 (C) ... to the nitrite and eventually to the nitrate (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Fat dispersed in water is exemplified by (A) Colloids (B) Gel (C) Butter (D) Emulsion

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Which one of the following statement is not valid for aerosols ?

Description : Which one of the following statement is not valid for aerosols ?

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Aerosols reduce primary productivity by :

Description : Aerosols reduce primary productivity by :

Last Answer : Aerosols reduce primary productivity by : A. Decreases `O_(2)` concentration B. Preventing `N_(2) ... C. Reducing photosynthesis D. None of the above.