MCQOPTIONS
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MCQOPTIONS
This section includes 552 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
Ultrafine grinders operate principally by |
| A. | slow compression |
| B. | impact |
| C. | attrition |
| D. | cutting action |
| Answer» D. cutting action | |
| 152. |
The most suitable filter for the removal of very small amount of precipitate from very large volumes of water is the __________ filter. |
| A. | vacuum |
| B. | sand |
| C. | plate & frame |
| D. | rotary |
| Answer» C. plate & frame | |
| 153. |
Capacity of flight conveyor in tons/hr is given by (where, W & D = width and depth of flight respectively in metre V = speed of the conveyor, metre/second ρ = bulk density of material, kg/m3)$ |
| A. | 3.6 W.D.V.ρ |
| B. | 3.6 W.D.V. |
| C. | 3.6 W.V.ρ |
| D. | 3.6 D.V.ρ |
| Answer» B. 3.6 W.D.V. | |
| 154. |
Crushing efficiency of a machine ranges between __________ percent. |
| A. | 0.1 to 2 |
| B. | 5 to 10 |
| C. | 20 to 25 |
| D. | 50 to 70 |
| Answer» B. 5 to 10 | |
| 155. |
The ratio of the actual mesh dimension of Taylor series to that of the next smaller screen is |
| A. | 2 |
| B. | 2 |
| C. | 1.5 |
| D. | 3 |
| Answer» C. 1.5 | |
| 156. |
Which of the following gives the work required for size reduction of coal to -200 mesh in a ball mill most accurately ? |
| A. | Rittinger's law |
| B. | Kick's law |
| C. | Bond's law |
| D. | none of these |
| Answer» B. Kick's law | |
| 157. |
Feed size of ‚â• 25 cms can be accepted by$ |
| A. | ball mill |
| B. | rod mill |
| C. | fluid energy mill |
| D. | jaw crusher |
| Answer» E. | |
| 158. |
Screw conveyors are |
| A. | run at very high rpm. |
| B. | suitable for sticky materials. |
| C. | suitable for highly abrasive materials. |
| D. | all (a), (b) and (c) |
| Answer» C. suitable for highly abrasive materials. | |
| 159. |
Power consumption during turbulent flow in agitation tank is proportional to the __________ of the liquid. |
| A. | viscosity |
| B. | thermal conductivity |
| C. | surface tension |
| D. | density |
| Answer» E. | |
| 160. |
Mass flow of granular solid (M) through a circular opening of dia, D follows |
| A. | M ‚àù D |
| B. | M ‚àù D2 |
| C. | M ‚àù D3 |
| D. | M ‚àù D |
| Answer» D. M ‚àù D | |
| 161. |
The constants (Kb, Kr and Kk) used in the laws of crushing (i.e., Bond's law, Rittinger's law and Kick's law) depend upon the |
| A. | feed material. |
| B. | type of crushing machine. |
| C. | both (a) & (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 162. |
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 |
| Answer» C. 22.1 Œºm/s | |
| 163. |
The specific cake resistance for incompressible sludges is (where ΔP = pressure drop over cake)$ |
| A. | ∝ ΔP |
| B. | ∝ 1/ ΔP |
| C. | ∝ ΔP |
| D. | independent of ΔP |
| Answer» E. | |
| 164. |
__________ mean diameter of particles is given by |
| A. | Mass |
| B. | volume |
| C. | Arithmetic |
| D. | Volume surface |
| Answer» C. Arithmetic | |
| 165. |
Filtration capacity of a rotary drum vacuum filter depends upon the |
| A. | cake thickness. |
| B. | characteristics of the feed slurry. |
| C. | both (a) & (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 166. |
Separation of isotopes is generally done using a/an __________ centrifuge. |
| A. | ultra |
| B. | disk-bowl |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» B. disk-bowl | |
| 167. |
Height of liquid in agitation tank is normally maintained equal to the tank diameter. However, if the tank is too tall and a large liquid hold up is desired, then two or more impellers mounted on the same shaft may be used. The clearance between the tank bottom and the bottom most impeller should be about (where, D = impeller diameter) |
| A. | 0.5 D |
| B. | D |
| C. | 1.5 D |
| D. | 2 D |
| Answer» C. 1.5 D | |
| 168. |
The grinding in a hammer crusher takes place due to the |
| A. | attrition |
| B. | impact |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 169. |
Gyratory crushers compared to the reciprocating jaw crushers |
| A. | have greater capacity per unit of discharge area. |
| B. | crush intermittantly. |
| C. | are less suitable for coarse materials. |
| D. | have less steady power consumption. |
| Answer» B. crush intermittantly. | |
| 170. |
__________ is defined as the geometric mean of the relative rejections and the relative recoveries of two minerals. |
| A. | Separation efficiency |
| B. | Selectivity index |
| C. | Concentration ratio |
| D. | none of these |
| Answer» C. Concentration ratio | |
| 171. |
Vertical transportation of materials can be done by a/an |
| A. | apron conveyor |
| B. | pneumatic conveyor |
| C. | bucket elevator |
| D. | both(b)&(c) |
| Answer» E. | |
| 172. |
For achieving maximum capacity of the ball mill, the ball charge should be equal to about __________ percent of the ball mill volume. |
| A. | 10 |
| B. | 25 |
| C. | 50 |
| D. | 75 |
| Answer» D. 75 | |
| 173. |
Horsepower required for a roll crusher is directly proportional to its |
| A. | reduction ratio. |
| B. | capacity. |
| C. | both (a) & (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 174. |
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 |
| Answer» C. fine | |
| 175. |
The most suitable equipment for removing the fine dust particle (< 1 micron dia.) from air below its dew point will be a/an |
| A. | bag filter |
| B. | electrostatic precipitator |
| C. | cyclone separator |
| D. | wet scrubber |
| Answer» C. cyclone separator | |
| 176. |
The sphericity of a solid particle of cubical shape is |
| A. | π |
| B. | (π/6)1/3 |
| C. | (π/6)1/2 |
| D. | π/3 |
| Answer» C. (œÄ/6)1/2 | |
| 177. |
All resistances during washing of cake |
| A. | increases |
| B. | decreases |
| C. | remain constant |
| D. | none of these |
| Answer» D. none of these | |
| 178. |
Which of the following represents the plot of filtrate volume versus time for constant pressure filtration ? |
| A. | Parabola |
| B. | Straight line |
| C. | Hyperbola |
| D. | Exponential curve |
| Answer» B. Straight line | |
| 179. |
A sand mixture was screened through a standard 10-mesh screen. The mass fraction of the oversize material in feed, overflow and underflow were found to be 0.38, 0.79 and 0.22 respectively. The screen effectiveness based on the oversize is |
| A. | 0.5 |
| B. | 0.58 |
| C. | 0.68 |
| D. | 0.62 |
| Answer» B. 0.58 | |
| 180. |
In a mixer, the quantity, (v. L/D) is termed as __________ number(where, v = longitudinal velocity of material, L = length of the mixer, D = diffusivity in axial mixing). |
| A. | Weber |
| B. | Peclet |
| C. | Brinkman |
| D. | Schmidt |
| Answer» C. Brinkman | |
| 181. |
The main differentiation factor between tube mill and ball mill is the |
| A. | length to diameter ratio. |
| B. | size of the grinding media. |
| C. | final product size. |
| D. | operating speed. |
| Answer» B. size of the grinding media. | |
| 182. |
__________ 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 |
| Answer» E. | |
| 183. |
Pick out the wrong statement pertaining to the turbine agitator. |
| A. | Recommended peripheral speed for the turbine agitator is 200-250 metres/minute. |
| B. | Pitched blade turbine agitator gives only radial flow with complete absence of the axial flow. |
| C. | Generally, the diameter of the agitator is kept between l/3rd to l/6th of the tank diameter while the blade length is l/4th of agitator diameter (with central disc, it is l/8th of the agitator diameter). |
| D. | Turbine agitator should be located at a height not less than one agitator diameter length from the bottom. If the depth of liquid in the tank is more than twice the agitator diameter, two agitators should be used. |
| Answer» C. Generally, the diameter of the agitator is kept between l/3rd to l/6th of the tank diameter while the blade length is l/4th of agitator diameter (with central disc, it is l/8th of the agitator diameter). | |
| 184. |
The material is crushed in a gyratory crusher by the action of |
| A. | impact |
| B. | compression |
| C. | attrition |
| D. | cutting |
| Answer» C. attrition | |
| 185. |
Hot, lumpy & abrasive materials are best transported by using a/an __________ conveyor. |
| A. | apron |
| B. | belt |
| C. | screw |
| D. | flight |
| Answer» B. belt | |
| 186. |
Which of the following is not an industrial screening equipment ? |
| A. | Sharpies centrifuge |
| B. | Vibrating screen |
| C. | Grizzly |
| D. | Trommel |
| Answer» B. Vibrating screen | |
| 187. |
Washability curve based on float and sink test enables an assessment to be made of the possibility of cleaning a coal fraction based on the |
| A. | density separation. |
| B. | differential wettability. |
| C. | size. |
| D. | volatile matter content. |
| Answer» B. differential wettability. | |
| 188. |
__________ are mixed using ribbon blenders. |
| A. | Lumpy solids and low viscosity liquids |
| B. | Dry powders |
| C. | High viscosity liquids |
| D. | Thick pastes |
| Answer» C. High viscosity liquids | |
| 189. |
Gold ore concentration is mostly done using |
| A. | jigging |
| B. | tabling |
| C. | froth floatation |
| D. | elutriation |
| Answer» C. froth floatation | |
| 190. |
If radius of a batch basket centrifuge is halved & the r.p.m. is doubled, then the |
| A. | linear speed of the basket is doubled. |
| B. | linear speed of the basket is halved. |
| C. | centrifugal force is doubled. |
| D. | capacity of centrifuge is increased. |
| Answer» D. capacity of centrifuge is increased. | |
| 191. |
Which of the following agitators having a large blade area, rotating at slow speed is used for mixing high viscosity liquids ( > 50000 centipoise) ? |
| A. | Propeller |
| B. | Helical screw |
| C. | Flat blade turbine |
| D. | Curved blade turbine |
| Answer» C. Flat blade turbine | |
| 192. |
Filtration operation carried out by continuous increase of the inlet pressure of slurry, is called the __________ filtration. |
| A. | constant rate |
| B. | varying pressure |
| C. | varying rate |
| D. | constant pressure |
| Answer» B. varying pressure | |
| 193. |
In constant pressure filtration, |
| A. | resistance decreases with time |
| B. | rate of filtration is constant |
| C. | rate of filtration increases with time |
| D. | rate of filtration decreases with time |
| Answer» E. | |
| 194. |
Filter medium resistance is important during the __________ of filtration. |
| A. | early stages. |
| B. | final stages. |
| C. | entire process. |
| D. | none of these. |
| Answer» B. final stages. | |
| 195. |
General crushing equation is given by . Bond's crushing law isobtained by solving this equation for n = __________ and feed of infinite size. |
| A. | 1 |
| B. | 1.5 |
| C. | 2 |
| D. | 2.5 |
| Answer» C. 2 | |
| 196. |
In classification, particles are said to be equal settling, if they have the same terminal velocities in the |
| A. | different fluids |
| B. | same fluid |
| C. | same field of force |
| D. | both (b) and (c) |
| Answer» E. | |
| 197. |
Reciprocating screens are normally inclined at an angle of 5° with the horizontal and employ gyratory motion at feed end & reciprocating motion at the discharge end. They are not suitable for the screening of the$ |
| A. | light metal powder down upto 4 meshsize. |
| B. | dry chemicals. |
| C. | heavy tonnages of rocks or gravel. |
| D. | powdered food & granular materials. |
| Answer» D. powdered food & granular materials. | |
| 198. |
Which of the following is not used as filter aid? |
| A. | Asbestos |
| B. | Diatomaceous earth |
| C. | Purified wood cellulose |
| D. | Rice husk |
| Answer» E. | |
| 199. |
For the preliminary breaking of hard rock, we use a |
| A. | gyratory crusher |
| B. | ball mill |
| C. | tube mill |
| D. | squirrel-cage disintegrator |
| Answer» B. ball mill | |
| 200. |
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) |
| Answer» E. | |