Which of the following is an undesirable property in a tower packing?
(A) Large surface per unit volume
(B) Large free cross-section
(C) Low weight per unit volume
(D) Large weight of liquid retained
Description : An ideal tower packing should not (A) Have low weight per unit volume (B) Have large surface area per unit volume (C) Have large free cross-section (D) Hold up large amount of liquid in the packing
Last Answer : (D) Hold up large amount of liquid in the packing
Description : Channelling in a packed tower results from the (A) High pressure drop (B) Maldistribution of liquid (C) Non-uniformity of packing (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the ... of liquid, problem of channelling, loading & flooding is generally encountered in packed towers
Last Answer : (C) Diameter of randomly packed tower is normally more than 1.2 metres
Description : ick out the undesirable property for a good refrigerant. (A) High thermal conductivity (B) Low freezing point (C) Large latent heat of vaporisation (D) High viscosity
Last Answer : (D) High viscosity
Description : Which of the following is an undesirable property of a manometricliquid? (A) Non-sticky & non-corrosive nature (B) High vapour pressure (C) Low viscosity & surface tension (D) Low co-efficient of thermal expansion
Last Answer : (B) High vapour pressure
Description : High __________ is an undesirable property for a good refrigerant. (A) Specific heat (B) Latent heat of vaporisation (C) Viscosity (D) Specific vapor volume
Last Answer : (C) Viscosity
Description : For aluminium, as compared to copper, all the following factors have higher values except (a) specific volume (6) electrical conductivity (c) co-efficient of linear expansion (d) resistance per unit length for same cross-section
Last Answer : (6) electrical conductivity
Description : Blowdown in a cooling tower (A) Means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities (B) Increases the scale forming tendencies of water (C) Is undesirable (D) All (A), (B) & (C)
Last Answer : (A) Means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities
Description : Which of the following is an undesirable property for an absorbingsolvent? (A) Low vapour pressure (B) Low velocity (C) Low freezing point (D) None of these
Last Answer : (D) None of these
Description : Which of the following is an undesirable property of slag produced during the Pyrometallurgical method of metal extraction from its ore? (A) High fusibility & fluidity (B) High thermal conductivity (C) Low density (D) High chemical activity
Last Answer : B) High thermal conductivity
Description : In a moderately sized packed absorption tower, channelling (which is most severe with stacked packings) can be minimised by taking the ratio of tower diameter to packing diameter (A) > 4 :1 (B) < 8 : 1 (C) > 8:1 (D) < 6:1
Last Answer : (C) > 8:1
Description : Pressure drop through plate tower as compared to that through packed tower, for the same duty will be (A) Less (B) More (C) Equal (D) Either (A) or (B); depends on the packing height
Last Answer : (B) More
Description : In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of (A) Area between operating line and 45° diagonal x-y diagram (B) Condenser and reboiler surfaces (C) Tower cross-section (D) None of these
Last Answer : (A) Area between operating line and 45° diagonal x-y diagram
Description : In case of laminar flow of fluid through a circular pipe, the (A) Shear stress over the cross-section is proportional to the distance from the surface of the pipe (B) Surface of velocity distribution is a ... occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)
Last Answer : (B) Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder
Description : Normal force acting per unit cross sectional area is called A. weight B. pressure C. volume D. friction
Last Answer : pressure
Description : In which of the following cases, it is possible for flow to occur from low pressure to high pressure? (A) Flow of liquid upward in a vertical pipe (B) Flow through a converging section (C) Flow of air downward in a pipe (D) Impossible in a constant cross-section conduit
Last Answer : (B) Flow through a converging section
Description : When incrementally placing a large composite resin restoration, what effect does an air-inhibited layer on the surface of the first increment have on the bond between the first and the second increments? A. ... B. It is desirable and improves the bond C. It is undesirable and should be removed
Last Answer : B. It is desirable and improves the bond
Description : Pick out the wrong statement. (A) Higher specific gravity of petroleum products means higher C/H ratio (B) Aromatics have lower specific gravity than corresponding paraffins (C) Hydrocarbons of low ... of high specific gravity (e.g., aromatics) possess the maximum thermal energy per unit weight
Last Answer : (B) Aromatics have lower specific gravity than corresponding paraffins
Description : The weight per unit volume of a liquid at a standard temperature and pressure is called (A) Specific weight (B) Mass density (C) Specific gravity (D) None of these
Last Answer : Answer: Option A
Description : The mass per unit volume of a liquid at a standard temperature and pressure is called (A) Specific weight (B) Mass density (C) Specific gravity (D) None of these
Last Answer : Answer: Option B
Description : The ability of an atom to absorb neutrons is its neutron capture cross section. The unit of measurement for neutron capture cross section is: w) the nucleus volume x) capture capacity y) resonance quotient z) barn
Last Answer : ANSWER: Z -- BARN
Description : The pulmonary ventilation frequency (number of inhalations per time unit) rises or lowers the carbon dioxide concentration in blood. If it is intense the gas is more eliminated to the exterior and if it ... carbon dioxide and also of more hydrogen ions spending and the pH of the solution is raised.
Last Answer : What are acidosis and alkalosis?
Description : Crystallisation of polymers is an undesirable property. Crystallisation of celluloid is prevented by adding (A) Glycerol (B) Nitro cellulose (C) Camphor (D) None of these
Last Answer : (C) Camphor
Description : Pick out the undesirable property for a solvent meant for dewaxing of lube oil. (A) Complete miscibility with oil (B) High solubility of wax in the solvent (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) and (B)
Description : CMOS circuits are extensively used for ON-chip computers mainly because of their extremely (A) low power dissipation. (B) high noise immunity. (C) large packing density. (D) low cost.
Last Answer : Ans: C Because CMOS circuits have large packing density.
Description : Pick out the wrong statement. (A) When the concentration difference for the mass transfer becomes zero at the bottom of the gas absorption tower, then the upper end of the operating line touches the ... fixed gas flow rate, the slope of the operating line decreases, in case of gas absorption process
Last Answer : (C) The operating line lies above the equilibrium curve in case of a gas desorber
Description : If the path of liquid across the plate is very long as in case of large diameter tower, Murphree efficiency can be __________ percent (A) 100 (B) > 100 (C) < 100 (D) None of these
Last Answer : (B) > 100
Description : The most common packing used in industrial operations is __________ rings. (A) Raschig (B) Lessing (C) Cross-partition (D) Single spiral
Last Answer : (C) Cross-partition
Description : A coal with high ash content is undesirable, as (A) It is abrasive to the coal pulveriser (i.e. ball mill) and the combustion chamber (B) The ash in molten condition gets absorbed in the pores of the ... and stick to the boiler tubes thereby reducing the heat transfer (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Assertion : If a current flows through a wire of non-uniform cross-section, potential difference per unit length of wire is same throughout the length
Last Answer : Assertion : If a current flows through a wire of non-uniform cross-section, potential difference per ... . If Assertion is false but Reason is true.
Description : Semibatch reactor is preferred, when a/an (A) A highly exothermic reaction is to be controlled (B) Undesirable side reaction (at high concentration of one of the reactants) is to be avoided (C) A gas is to be reacted with liquid (e.g. hydrogenation of fat) (D) All (A), (B), and (C
Last Answer : (D) All (A), (B), and (C
Description : The interfacial area per unit volume of dispersion, in a gas-liquid contactor, for fractional hold up of gas = 0.1 and gas bubble diameter = 0.5 mm is given by (in m2 /m3 ) (A) 500 (B) 1200 (C) 900 (D) 800
Last Answer : (A) 500
Description : Surface preparation for Metallising the abrasives used for final cleaning is a) Chilled iron grit G.24, as defined in BS : 2451 b) Washed salt free angular silica sand of mesh size 12 to 30 with a minimum of 40% retained on a 20 mesh c) either (a) or (b) * d) d) neither (a) or (b)
Last Answer : c) either (a) or (b) *
Description : In an absorber, HETP does not vary with the (A) Flow rate of liquid (B) Flow rate of gas (C) Type and size of packing (D) None of these
Description : Lower temperature and large excess of ammonia in urea melt (A) Increases biuret formation (B) Decreases biuret formation (C) Is undesirable (D) Does not effect biuret formation
Last Answer : (B) Decreases biuret formation
Description : Rail section is generally designated by its A. Total weight B. Total length C. Weight per metre length D. Area of its cross-section
Last Answer : C [Weight per metre length] Explanation: The rail section is designated by its weight in 1b/yard or in kg/m. The standard rail sections in use on Indian Railways are 60 kg/m, 52 kg/m and 9OR ... 60R for MG and 50R for NG. In India, the standard rails are either of medium manganese or carbon steels.
Description : If At is the area of steel cross-section, t is working stress, L is width of road and W is weight of slab per square metre, the spacing of the tie bars for a longitudinal joint, is (A) (100 At × t)/WL (B) 100 At/tWL (C) (100 WAt × t)/tL (D) 100 WL/At t
Last Answer : Answer: Option D
Description : Mark correct option a) In Head Record offices one key of the safe will be retained in the custody of HRO and other one is Accountant. b) The insured seal supplied to the set of mail office ... supplied with a portfolio with lock & key bearing designation of section d) All the above are correct.
Last Answer : d) All the above are correct.
Description : Pick up the incorrect statement from the following: (A) The retaining wall should be structurally capable to resist the applied earth pressure (B) The section of the retaining wall should be so ... off water from the earth retained, weep holes are provided near the top of the retaining wall
Description : For specified tube outside diameter, higher BWG means higher (A) Tube thickness (B) Cross-sectional area (C) Weight per unit length (D) None of these
Last Answer : (B) Cross-sectional area
Description : Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the (A) Packing may be crushed due to thermal expansion/contraction of the ... C) Viscosity variation of the fluids may cause channelling/flooding (D) None of these
Last Answer : (A) Packing may be crushed due to thermal expansion/contraction of the components of the equipments
Description : Baffles in the shell side of a shell and tube heat exchanger (A) Increase the cross-section of the shell side liquid (B) Force the liquid to flow parallel to the bank (C) Increase the shell side heat transfer co-efficient (D) Decrease the shell side heat transfer co-efficient
Last Answer : (C) Increase the shell side heat transfer co-efficient
Description : Vena-contracta formed during flow of a liquid through an orificemeter has (A) Minimum liquid cross-section (B) More diameter compared to orifice diameter (C) Minimum velocity of fluid stream (D) None of these
Last Answer : (A) Minimum liquid cross-section
Description : Rate of low temperature oxidation of coal due to bad storage conditions (A) Decreases with increase in surface area (B) Does not vary with increase in surface area (C) Is more for low volatile ... to high volatile coal (D) Is accelerated by storage in large heaps with small surface to volume ratio
Last Answer : (D) Is accelerated by storage in large heaps with small surface to volume ratio
Description : To avoid fire by spontaneous combustion of coal due to its low temperature oxidation, it should be stored in (A) Shallow and small piles (B) Fine sizes without the presence of any lump (C) Closed space without any ventilation facility (D) Large heaps with small surface to volume ratio
Last Answer : (A) Shallow and small piles
Description : Spontaneous combustion of coal on storage results due to (A) Inadequate ventilation (B) Low temperature oxidation (C) Storage in large heaps with small surface to volume ratio (D) All (A), (B) and (C)
Description : Specific surface area is the surface area of a unit __________ of materials. (A) Weight (B) Volume (C) Either (A) or (B) (D) Neither (A) nor (B)
Last Answer : (C) Either (A) or (B)
Description : Use of raschig rings in place of crushed stones as packing in packed beds (other things being same) (A) Increases pressure drop, increases surface area (B) Increases pressure drop, decreases ... (C) Decreases pressure drop, increases surface area (D) Decreases pressure drop, decreases surface area
Last Answer : (C) Decreases pressure drop, increases surface area
Description : Mercaptans are (A) Low boiling sulphur compounds (B) Added in LPG cylinders to detect gas leakage by its smell (C) Undesirable in petrol, as they reduce its octane number (D) All (A), (B) and (C)
Description : Which of the following is an undesirable characteristic for the solvent used in gas absorption? (A) Low vapor pressure (B) Low viscosity (C) High gas solubility (D) None of these