Description : Colloidal mills are used for __________ grinding. (A) Coarse (B) Intermediate (C) Fine (D) Ultrafine
Last Answer : (D) Ultrafine
Description : Gravity stamp mill is meant for the __________ crushing. (A) Primary (B) Intermediate (C) Fine (D) Ultrafine
Last Answer : (C) Fine
Description : Temperature of the product during ultrafine grinding (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease; depends on the material being ground
Last Answer : (A) Increases
Description : Which of the following size reduction equipments employs mainly attrition for ultrafine grinding? (A) Jet mills (B) Fluid energy mill (C) Micronizer (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Wet grinding in a revolving mill __________ as compared to dry grinding. (A) Gives less wear on chamber walls (B) Requires more energy (C) Increases capacity (D) Complicates handling of the product
Last Answer : (C) Increases capacity
Description : Work index is the gross energy (kWh/tonne of feed) necessary to reduce a very large feed to such a size that 80% of product particles will pass through a 0.1 mm screen. The value of work index determined for wet grinding should ... to get the same for dry grinding. (A) 1.0 (B) 0.5 (C) 1.34 (D) 4.34
Last Answer : (C) 1.34
Description : In case of grinding in a ball mill (A) Wet grinding achieves a finer product size than dry grinding (B) Its capacity decreases with increasing fineness of the products (C) Grinding cost and power requirement increases with increasing fineness of the products (D) All (A), (B) and (C)
Description : In case of a revolving mill, wet grinding compared to dry grinding (A) Requires more energy (B) Has less capacity (C) Complicates handling & classification of the product (D) None of these
Last Answer : (D) None of these
Description : Actual operating speed of a ball mill may vary from 65 to 80% of the critical speed. Which of the following duties would require the ball mill to be operated at maximum percentage of critical speed? (A) ... of large particles (upto 1.25 cms) (D) Dry grinding of large particles in un-baffed mills
Last Answer : (D) Dry grinding of large particles in un-baffed mills
Description : Pick out the wrong statement. (A) For the compressible cake, voidage & the specific resistance of the cake can be assumed to be constant (B) Cake resistance is independent of the pressure ... Crushing of explosive materials are done by employing dry-grinding (D) Gyratory crusher is a coarse crusher
Last Answer : (B) Cake resistance is independent of the pressure drop
Description : Use of grinding aids results in the (A) Enhanced production rate (B) Finer products (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (D) Neither (A) nor (B)
Description : For the transportation of ultrafine particles, the equipment used is a __________ conveyor. (A) Belt (B) Pneumatic (C) Screw (D) None of these
Last Answer : (B) Pneumatic
Description : In a size reduction crushing operation, feed size is 100 to 300 mm. while the product size is 10 to 50 mm. This is a case of the __________ crushing. (A) Primary (B) Secondary (C) Fine (D) Ultrafine
Last Answer : (B) Secondary
Description : In a size reduction crushing operation, feed size is 300 to 1500 mm while the product size is 100 to 300 mm. This is a case of the __________ crushing. (A) Secondary (B) Fine (C) Primary (D) Ultrafine
Last Answer : (C) Primary
Description : Pick out the wrong statement. (A) Close circuit grinding is more economical than open circuit grinding (B) Cod oil, beef tallow or aluminium stearates are used as grinding aids in cement ... is called a classifier (D) Size enlargement is a mechanical operation exemplified by medicinal tablet making
Last Answer : (C) The equipment used for the removal of traces of solids from a liquid is called a classifier
Description : The main size reduction operation in ultrafine grinders is (A) Cutting (B) Attrition (C) Compression (D) Impact
Last Answer : (B) Attrition
Description : Which of the following is not an ultrafine grinder (colloid mill)? (A) Micronizers (B) Agitated mills and fluid energy mills (C) Toothed roll crusher (D) Hammer mills with internal classification
Last Answer : (C) Toothed roll crusher
Description : To get ultrafine particles, the equipment used is a (A) Ball mill (B) Rod mill (C) Hammer crusher (D) Fluid energy mill
Last Answer : (D) Fluid energy mill
Description : Ultrafine grinders operate principally by (A) Slow compression (B) Impact (C) Attrition (D) Cutting action
Last Answer : (C) Attrition
Description : Fluid energy mill comes in the category of (A) Grinder (B) Crusher (C) Cutter (D) Ultrafine grinder
Last Answer : (D) Ultrafine grinder
Description : Size measurement of ultrafine particles can be best expressed in terms of (A) Centimetre (B) Screen size (C) Micron (D) Surface area per unit mass
Last Answer : (D) Surface area per unit mass
Description : Natural gas recovered along with crude oil from oil wells is called wet natural gas which has a higher __________ compared to the dry natural gas. (A) Unsaturated hydrocarbon content (B) Calorific value (C) Quantity of propane (D) Quantity of butane
Last Answer : (B) Calorific value
Description : __________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid. (A) Dew point (B) Bubble point (C) Dry bulb temperature (D) Wet bulb temperature
Last Answer : (A) Dew point
Description : Dry bulb temperature of unsaturated air is more than its __________ temperature. (A) Dew point (B) Wet bulb (C) Both 'a' & 'b' (D) Neither 'a' nor 'b
Last Answer : (C) Both 'a' & 'b
Description : __________ temperature is the steady state temperature attained by a small amount of liquid evaporating into a large quantity of unsaturated gasvapor mixture. (A) Dry bulb (B) Wet bulb (C) Dew point (D) None of these
Last Answer : (B) Wet bulb
Description : The temperature to which a vapour gas mixture must be cooled (at varying humidity) to become saturated is called the __________ temperature. (A) Dew point (B) Wet bulb (C) Dry bulb (D) None of these
Description : Dry bulb temperature of the gas is __________ the wet bulb temperature. (A) Less than (B) More than (C) Equal to (D) None of these
Last Answer : (B) More than
Description : Wet bulb and dry bulb temperatures becomes identical at __________ percent saturation curve. (A) 100 (B) 50 (C) 78 (D) None of these
Last Answer : (A) 100
Description : The temperature of water cooled in cooling tower is always __________ temperature of entering air. (A) More than the wet bulb (B) Less than the wet bulb (C) Equal to the wet bulb (D) Equal to the dry bulb
Last Answer : (A) More than the wet bulb
Description : Steady state temperature reached by a small amount of liquid evaporating into a large amount of unsaturated vapour-gas mixture is called the __________ temperature. (A) Dry-bulb (B) Wet-bulb (C) Dew point (D) Adiabatic saturation
Last Answer : (B) Wet-bulb
Description : The wet and 'dry bulb temperature for a vapour-gas mixture are 25°C and 30°C respectively. If the mixture is heated to 45°C at constant pressure, the wet bulb temperature will be __________ °C. (A) 25 (B) > 25 (C) < 25 (D) - 25
Last Answer : (B) > 25
Description : To remove all the moisture from a wet solid it requires exposure to __________ air. (A) Perfectly dry (B) Highly humid (C) High temperature (D) None of these
Last Answer : (A) Perfectly dry
Description : The minimum temperature to which the water can be cooled in a cooling tower is the __________ temperature of air. (A) Ambient (B) Dry bulb (C) Dew point (D) Wet bulb
Last Answer : C) Dew point
Description : Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature
Last Answer : (D) Dew point temperature
Description : __________ temperature remains constant during adiabatic saturation process of unsaturated air. (A) Dew point (B) Dry bulb (C) Wet bulb (D) None of these
Last Answer : (C) Wet bulb
Description : Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air. (A) Wet bulb (B) Dry bulb (C) Saturation (D) Dew point
Last Answer : Option A
Description : The wet bulb temperature is lower in dry air than in wet air at the same temperature. A dry bulb thermometer registers a higher temperature than a wet bulb thermometer except at __________ percent relative humidity. (A) 0 (B) 100 (C) 50 (D) None of these
Last Answer : Option B
Description : psychrometer does not measure the __________ temperature of moist air. (A) Dew point (B) Dry bulb (C) Wet bulb (D) None of these
Description : The dew point of moist air becomes __________ with decrease in its relative humidity. (A) Less than the wet bulb temperature (B) More than the wet bulb temperature (C) More than the dry bulb temperature (D) Equal to wet bulb temperature
Description : __________ remains constant during the adiabatic cooling of moist air. (A) Wet bulb temperature (B) Dry bulb temperature (C) Relative humidity (D) Specific humidity
Description : 3. __________ mill is normally used for grinding of talc. (A) Tube (B) Compartment (C) Ring-roll (D) Pebble
Last Answer : (A) Tube
Description : A __________ mill is a revolving mill divided into two or more sections by perforated partitions in which preliminary grinding takes place at one end and the finishing grinding at the discharge end. (A) Compartment (B) Tube (C) Rod (D) Pebble
Last Answer : (A) Compartmen
Description : __________ mill is not used for grinding wheat into flour and for milling of cereals & other vegetable products. (A) Buhrstone (B) Roller (C) Attrition (D) Pebble
Last Answer : (D) Pebble
Description : __________ balls capable of grinding the feed in a ball mill gives the maximum efficiency. (A) Cast iron (B) Minimum size (C) Maximum size (D) Elliptical
Last Answer : (B) Minimum size
Description : In a grinding operation, the limiting particle size is the size of the __________ particle in the sample. (A) Smallest (B) Largest (C) Either (A) or (B) (D) Neither (A) nor (B)
Description : Grinding efficiency of a ball mill is of the order of __________ percent. (A) 1-5 (B) 40-50 (C) 75-80 (D) 90-95
Last Answer : (A) 1-5
Description : For grinding of softer materials, the grinding wheel should have __________ grain size. (A) Finer (B) Coarser (C) Medium (D) Any type of
Last Answer : (B) Coarser
Description : In how many time final grinding should be done of new AT weld ? (i) Just after the welding (ii) After 8 hrs of welding (iii) With in 24 hrs* (iv) None of the above
Last Answer : iii) With in 24 hrs*
Description : Pick out the wrong statement. (A) Recycled coarse material to the grinder by a classifier is termed as circulating load (B) Wear and tear in wet crushing is more than that in dry crushing of ... a pipeline which permits the solids to settle down due to reduction in velocity of the dust laden gas
Last Answer : (C) Size enlargement (opposite of size reduction) is not a mechanical operation
Description : Pick out the wrong statement: (A) Magnetic separation method can be employed to treat both dry & wet ores (B) Reduction ratio in crushing operation is defined as the ratio of minimum feed ... ) Gyratory crusher is used for coarse crushing (D) Screens are of stationary, moving and vibratory types
Last Answer : (B) Reduction ratio in crushing operation is defined as the ratio of minimum feed size to the maximum product size