Description : The equation, Nst = (f/2)/[1 + 5 (Npr - 1) √(f/2)], corresponds to __________ analogy. (A) Von-Karman (B) Reynolds (C) Colburn (D) Prandtl
Last Answer : (D) Prandtl
Description : The equation, (NSt × N2/3 Pr ) = f/2, is the __________ analogy. (A) Colburn (B) Reynolds (C) Prandtl (D) None of these
Last Answer : (A) Colburn
Description : The equation, Nst = f/2, is the __________ analogy. (A) Colburn (B) Reynolds (C) Prandtl (D) None o
Last Answer : (B) Reynolds
Description : . For what value of Prandtl number, the Col-burn analogy is (A) 0.06 to 120 (B) 0.6 to 120 (C) 1 to 103 (D) 1 to 50
Last Answer : (B) 0.6 to 120
Description : According to Chilton-Colburn analogy for mass transfer, NSt .NSc 2/3 is equal to (A) f (B) f/2 (C) 2f (D) 1/f
Last Answer : (B) f/2
Description : Prandtl number for most of dry gases is about (A) 0.001 (B) 0.72 (C) 70 (D) 150
Last Answer : (B) 0.72
Description : Prandtl and Reynolds analogy are same, when Prandtl number is (A) 0.5 (B) 1 (C) > 2 (D) 1.5
Last Answer : (B) 1
Description : Pick out the wrong statement pertaining to the analogy between equations of heat and mass transfer operations. (A) Sherwood number in mass transfer is analogous to Nusselt number in heat transfer ... heat transfer (D) Reynolds number remains the same in both heat and mass transfer
Last Answer : (C) Reynolds number in mass transfer is analogous to Grashoff number in heat transfer
Description : Pick out the wrong statement. (A) Mechanical agitation is required, if the system has low interfacial tension (B) Sieve tray towers are generally used for systems having low ... Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers
Last Answer : (A) Mechanical agitation is required, if the system has low interfacial tension
Description : Prandtl mixing length is (A) Applicable to laminar flow problems (B) A universal constant (C) Zero at the pipe wall (D) None of these
Last Answer : (C) Zero at the pipe wall
Description : Pick out the wrong statement. (A) The Reynolds analogy for mass transfer is given by Lewis relation and is applicable, when Schmidt number is one (B) Sherwood number for flow in pipes can be expressed ... flux of a component A in binary mixture of A and B is given by - Dab'.dCA/dz
Last Answer : (C) According to film theory for equimolar counter diffusion, the mass transfer coefficient is given by DAB(B)P - 3, Q - 2
Description : Analogy between mass and heat transfer is not applicable in case of (A) Same velocity profile or equal eddy diffusivities (B) Thermal or pressure mass diffusion (C) Viscous heating or chemical reaction (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : If a solid shaft (diameter 20 cm, length 400 cm, N = 0.8 × 105 N/mm2 ) when subjected to a twisting moment, produces maximum shear stress of 50 N/mm2 , the angle of twist in radians, is (A) 0.001 (B) 0.002 (C) 0.0025 (D) 0.003
Last Answer : (C) 0.0025
Description : The specific gravity of urine normally ranges from (A) 0.900–0.999 (B) 1.003–1.030 (C) 1.000–1.001 (D) 1.101–1.120
Last Answer : B
Description : At what value of Prandtl number, conduction is negligible in the turbulent core of a fluid flowing through a heated pipe? (A) 0.5 (B) < 0.5 (C) > 0.6 (D) < 0.1
Last Answer : (C) > 0.6
Description : Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is (A) 0.2 (B) 0.4 (C) 0.6 (D) 0.8
Last Answer : (C) 0.6
Description : Which technique is applicable when other projects in the same analogy application domain have been completed? a) Algorithmic cost modelling b) Expert judgement c) Estimation by analogy d) Parkinson’s Law
Last Answer : c) Estimation by analogy
Description : Pick out the wrong statement. (A) Fluid movement under the influence of buoyant forces resulting from change in density takes place in case of natural convection (B) The ratio NNu /NRe . Npr is ... convection to that by conduction (D) The Colburn jH factor for heat transfer is given by Nst Npr
Last Answer : (D) The Colburn jH factor for heat transfer is given by Nst Npr
Description : Prandtl and Reynold's analogies are identical for Prandtl number value of (A) 0 (B) 0.5 (C) 1 (D) 5
Last Answer : (C) 1
Description : Value of Prandtl number for water ranges from (A) 1 to 2 (B) 5 to 10 (C) 100 to 500 (D) 1000 to 2000
Last Answer : (B) 5 to 10
Description : Thickness of thermal boundary layer is more compared to that of hydrodynamic boundary layer, when the value of Prandtl number is (A) 1 (B) < 1 (C) > 1 (D) > 5
Last Answer : (B) < 1
Description : For what value of Prandtl number, St = f/2? (A) 1.5 (B) 1 (C) > 1 (D) < 1
Description : At what value of Prandtl number, the hydrodynamic and thermal boundary layers of a fluid flowing over a heated plate will be identical? (A) 1 (B) < 1 (C) > 1 (D) None of these
Last Answer : (A) 1
Description : Critical value of the __________ number governs the transition from laminar to turbulent flow in free convection heat transfer. (A) Grashoff (B) Reynolds (C) Both 'a' & 'b' (D) Prandtl & Grashoff
Last Answer : (D) Prandtl & Grashoff
Description : Transition from laminar to turbulent zone in free convection heat transfer is governed by the critical value of (A) Grashoff number (B) Grashoff number & Reynolds number (C) Reynolds number (D) Grashoff number & Prandtl number
Last Answer : Option D
Description : Carbon content in steel is __________ percent. (A) 0.1-2 (B) 4-6 (C) 2-4 (D) 0.001-0.01
Last Answer : (A) 0.1-2
Description : Threshold limit value of copper in the atmospheric air is - (1) 0.001 mg/m3 (2) 0.01 mg/m3 (3) 1.0 mg/m3 (4) 5.0 mg/m3
Last Answer : (3) 1.0 mg/m3 Explanation: Inspirable copper dust takes a predominantly fibrous effect. The ALV of copper aerosol in the workplace atmosphere is 0.5 mg/m3, while the threshold limit value (TLV) is 1.0 mg/m3.
Description : Prandtl number for water at 20°C is about (A) 7 (B) 70 (C) 0.7
Last Answer : (A) 7
Description : Conduction occurs in the buffer zone for a fluid flowing through a heated pipe, only when Prandtl number is (A) 0.1 (B) > 1 (C) < 1 (D) 1
Last Answer : (A) 0.1
Description : An alkaline solution is used to reduce the concentration of carbon dioxide in a stream from 10% to 0.1% by absorption with irreversible chemical reaction. The overall number of transfer units based on gas phase is: (A) 9.21 (B) 4.605 (C) 100 (D) 0.001
Last Answer : (B) 4.605
Description : The difference in one unit of Rockwell hardness number corresponds to a difference in the depth of indentation of __________ mm. (A) 0.001 (B) 0.01 (C) 0.002 (D) 0.02
Last Answer : Option C
Description : A cantilever shaft has a diameter of 6 cm and the length is 40cm, it has a disc of mass 125 kg at its free end. The Young’s modulus for the shaft material is 250 GN/m2. Calculate the static deflection in nm. a) 0.001 b) 0.083c) 1.022 d) 0.065
Last Answer : a) 0.001
Description : When a constant discharge 2.91 litres/sec. was obtained in a pumping test, the draw downs in the test wells at 3 m and 6.184 m were 2.6 m and 0.3 m respectively. If over-all depth of the pumping well was 16 m, the ... (A) 0.0005 cm/sec (B) 0.001 cm/sec (C) 0.002 cm/sec (D) 0.01 cm/sec
Last Answer : Answer: Option B
Description : H2S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H2S ... by, y = 5x + 0.001 is (A) 2.0 (B) 1.56 (C) 1.0
Last Answer : (A) 2.0
Description : Solid content in most of the domestic sewage is about __________ percent. (A) 0.001 (B) 0.1 (C) 5 (D) 10
Last Answer : (B) 0.1
Description : TLV of mercury in potable (drinking) water is about __________ ppm. (A) 0.001 (B) 0.1 (C) 1 (D) 5
Last Answer : (A) 0.001
Description : Maximum permissible residual chlorine in treated water should be __________ mg/litre. (A) 0.001 to 0.01 (B) 0.2 to 0.3 (C) 2 to 3 (D) 5 to 10
Last Answer : (B) 0.2 to 0.3
Description : Very low pressure is expressed in microns (μ), which is equal to__________ mm of Hg column (absolute) at 0°C. (A) 0.0001 (B) 0.001 (C) 0.01 (D) 0.1
Last Answer : (B) 0.001
Description : Rotary vacuum pumps can reduce the absolute pressure to as low as __________ mm Hg. (A) 1 (B) 0.1 (C) 0.01 (D) 0.001
Last Answer : (C) 0.01
Description : Corresponding to Prandtl number in heat transfer, the dimensionless group in mass transfer is the __________ number. (A) Schmidt (B) Sherwood (C) Peclet (D) Stanton
Last Answer : (A) Schmidt
Description : Which of the following plays an important role in problems of simultaneous heat and mass transfer (A) Lewis number (B) Schmidt number (C) Prandtl number (D) Sherwood number
Last Answer : (A) Lewis number
Description : Nusselt number (for forced convection heat transfer) is a function of the __________ number. (A) Prandtl (B) Reynolds (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : Prandtl number is the ratio of (A) Mass diffusivity to thermal diffusivity (B) Momentum diffusivity to thermal diffusivity (C) Thermal diffusivity to mass diffusivity (D) Thermal diffusivity to momentum diffusivity
Last Answer : (B) Momentum diffusivity to thermal diffusivity
Description : Which of the following is unimportant in forced convection? (A) Reynolds number (B) Prandtl number (C) Grashoff number (D) None of these
Last Answer : (C) Grashoff number
Description : Dittus-Boelter equation cannot be used for molten metals mainly due to its very low (A) Prandtl number (B) Grashoff number (C) Thermal conductivity (D) Viscosity
Last Answer : (A) Prandtl number
Description : . If Prandtl number is greater than the Schmidt number, then the (A) Thermal boundary layer lies inside the concentration boundary layer (B) Concentration boundary layer lies inside the thermal boundary ... (D) Hydrodynamic (i.e., momentum) boundary layer is thicker than the other two
Last Answer : (A) Thermal boundary layer lies inside the concentration boundary layer
Description : The ratio of momentum diffusivity to thermal diffusivity is the __________ number. (A) Prandtl (B) Nusselt (C) Stanton (D) Grashoff
Last Answer : (A) Prandtl
Description : The ratio of kinematic viscosity to thermal diffusivity is called the __________ number. (A) Peclet (B) Prandtl (C) Stanton (D) Nusselt
Last Answer : (B) Prandtl
Description : Natural convection is characterised by (A) Grashoff number (B) Peclet number (C) Reynolds number (D) Prandtl number
Last Answer : (A) Grashoff number
Description : Prandtl number is the ratio of (A) Momentum diffusivity to mass diffusivity (B) Momentum diffusivity to thermal diffusivity (C) Thermal diffusivity to mass diffusivity (D) Thermal diffusivity to momentum diffusivity