Which of the following is the most controlling factor for the rate of
bubble detachment from the hot solid surface?
(A) Liquid density
(B) Liquid viscosity
(C) Hot surface temperature
(D) Interfacial tension
Description : For high sensivity of the bubble tube (A) A liquid of low viscosity is used (B) A liquid of low surface tension is used (C) The bubble space should be long (D) All the above
Last Answer : (D) All the above
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 : The individual mass transfer co-efficients (moles/m2s) for absorption of a solute from a gas mixture into a liquid solvent are, KL = 4.5 and KG = 1.5. The slope of the equilibrium line is 3. Which of ... A) Liquid side (B) Gas side (C) Interfacial (D) Both liquid and gas side
Last Answer : (B) Gas side
Description : 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
Last Answer : (D) Density
Description : Pressure exerted by a liquid depends upon its (A) Surface tension (B) Density (C) Viscosity
Last Answer : Option B
Description : The sensitiveness of a level tube decreases if (A) Radius of curvature of its inner surface is increased (B) Diameter of the tube is increased (C) Length of the vapour bubble is increased (D) Both viscosity and surface tension are increased
Last Answer : (D) Both viscosity and surface tension are increased
Description : A liquid disturbed by stirring comes to rest due to – (1) density (2) surface tension (3) viscosity (4) centripetal force
Last Answer : (3) viscosity Explanation: It happens because of viscosity. The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress. It is due to friction between neighboring parcels of the fluid that are moving at different velocities.
Description : For manometer, a better liquid combination is one having (A) Higher surface tension (B) Lower surface tension (C) Surface tension is no criterion (D) High density and viscosity
Last Answer : Answer: Option A
Description : A liquid disturbed by stirring comes to rest due to (1) density (2) surface tension (3) viscosity (4) centripetal force
Last Answer : viscosity
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 : Measurement of the interfacial area of mass transfer is achieved easily & accurately in case of a __________ column. (A) Spray (B) Packed (C) Bubble cap plate (D) Wetted wall
Last Answer : (D) Wetted wall
Description : Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for ... a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature
Last Answer : (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs
Description : 200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, Nc = 0.5 10 -3 kg/m2 .s. The initial ... moisture/kg dry solid). (A) 0.5 (B) 0.05 (C) 0.1 (D) 0.15
Last Answer : (C) 0.1
Description : What is the effect of temperature on surface tension and viscosity of a liquid?
Last Answer : Ans. Both decrease by increasing temperature.
Description : To get high tray efficiency (A) Interfacial surface between liquid and gas phase should be large (B) Time of contact between the two phases should be less (C) Gas velocity should be very low (D) Liquid entrainment should be severe
Last Answer : (A) Interfacial surface between liquid and gas phase should be large
Description : Existence of boundary layer in fluid flow is because of the (A) Surface tension (B) Fluid density (C) Fluid viscosity (D) Gravity forces
Last Answer : (C) Fluid viscosity
Description : The intensive properties are (A) Molar volume, density, viscosity and boiling point (B) Refractive index and surface tension (C) Both (A) and (B) (D) None of these
Last Answer : (C) Both (A) and (B)
Description : Spherical shape of mercury droplets is due to its (A) High viscosity (B) Low surface tension (C) High density (D) High surface tension
Last Answer : Option D
Description : Fractional solvent extraction (A) Employs only one solvent (B) Employs two solvents (C) Results in low interfacial tension (D) None of these
Last Answer : (B) Employs two solvents
Description : The buoyant force acting on a floating body is dependent on the (A) Viscosity of the liquid (B) Weight of the liquid displaced (C) Depth of immersion of the body (D) Surface tension of the liquid
Last Answer : (B) Weight of the liquid displaced
Description : A solid needle placed horizon-tally on the surface of the water floats due to – (1) capillary action (2) water pressure (3) surface tension of water (4) viscosity of water
Last Answer : (3) surface tension of water Explanation: A solid needle placed horizontally on the surface of water floats due to surface tension of water.
Description : A solid needle placed horizontally on the surface of the water floats due to (1) capillary action (2) water pressure (3) surface tension of water (4) viscosity of water
Last Answer : surface tension of water
Description : The rate of mass transfer is not dependent upon the (A) Degree of dispersion of one fluid in the other (B) Interfacial surface exposed between the phases (C) Both (A) & (B) (D) None of these
Last Answer : (D) None of these
Description : A large ship can float but a steel needle sinks because of (a) Viscosity (b) Surface tension (c) Density (d) None of these
Last Answer : Ans:(d)
Description : Alcohol is more volatile than water because ______ is lower than water. (1) its boiling point (2) its density (3) its viscosity (4) its surface tension
Last Answer : (1) its boiling point Explanation: Drinking alcohol (ethanol) and a lot of other simple alcohols are more volatile than water because they are less polar. Thus, alcohol has higher vapor pres-sure and ... C is what makes it possible to distill alcohol into a much stronger solution than wine or beer.
Description : Water drops are spherical because of - (1) viscosity (2) density (3) polarity (4) surface tension
Last Answer : (4) surface tension Explanation: Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by ... absence of other forces, including gravity, drops of virtually all liquids would be approximately spherical.
Description : Rise of oil a wick is due to – (1) density of the oil (2) viscosity of the oil (3) surface tension of the oil (4) pressure of the oil
Last Answer : (3) surface tension of the oil Explanation: The phenomenon of rise or fall of liquid in a capillary tube is called capillarity. Oil rises through a wick due to capillarity. The narrow ... tiny capillaries, through which oil rises. Capillary action is the result of adhesion and surface tension.
Description : Alcohol is more volatile than water because _________ is lower than water. (1) its boiling point (2) its density (3) its viscosity (4) its surface tension
Last Answer : its boiling point
Description : Rise of oil a wick is due to (1) density of the oil (2) viscosity of the oil (3) surface tension of the oil (4) pressure of the oil
Last Answer : surface tension of the oil
Description : Pick out the wrong statement. (A) Bubble size increases with the dynamic viscosity of the liquid in case of nucleate pool boiling (B) Thermal conductivity of a dry material is more than ... in kg/hr in an evaporator (D) Vaporisation of organic substances in evaporator mostly causes foam formation
Last Answer : (B) Thermal conductivity of a dry material is more than that of the damp material
Description : Venturimeter is used to measure: (1) rate of flow of liquids (2) liquid pressure (3) surface tension (4) liquid density
Last Answer : rate of flow of liquids
Description : The process of diffusion of one liquid into the other through a semi permeable membrane is called (A) Viscosity (B) Osmosis (C) Surface tension (D) Cohesion
Last Answer : Answer: Option B
Description : The property of a liquid which offers resistance to the movement of one layer of liquid over another adjacent layer of liquid, is called (A) Surface tension (B) Compressibility (C) Capillarity (D) Viscosity
Last Answer : Answer: Option D
Description : The mercury does not wet the glass. This is due to the property of the liquid known as (A) Cohesion (B) Adhesion (C) Viscosity (D) Surface tension
Description : Mercury does not wet glass. This is due to property of liquid known as (A) Adhesion (B) Cohesion (C) Surface tension (D) Viscosity
Last Answer : Answer: Option C
Description : Free surface of a liquid tends to contract to the smallest possible area due to force of (A) Surface tension (B) Viscosity (C) Friction (D) Cohesion
Description : The variation in the volume of a liquid with the variation of pressure is called its (A) Surface tension (B) Compressibility (C) Capillarity (D) Viscosity
Description : The tendency of a liquid surface to contract is due to the following property (A) Cohesion (B) Adhesion (C) Viscosity (D) Surface tension
Description : Which one of the following statements is correct ? a) For water at 100o Celsius at sea level, the vapour pressure is equal to atmospheric pressure b) Surface energy (or tension) is caused by ... it both in static and in dynamic conditions d) Air is 50,000 times more compressible than water
Last Answer : c) Viscosity of a fluid is the property exhibited by it both in static and in dynamic conditions
Description : Which of the following is the term used for the resistance of a liquid system to flow? w) surface tension x) diffusion y) viscosity
Last Answer : ANSWER: Y -- VISCOSITY
Description : Rate of heat transfer by vaporisation from pools of water is affected by the (A) Nature of heating surface and distribution of bubbles (B) Surface tension of water (C) Viscosity of water (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : The ratio of specific weight of a liquid to the specific weight of pure water at a standard temperature is called (A) Density of liquid (B) Specific gravity of liquid (C) Compressibility of liquid (D) Surface tension of liquid
Description : A coalescer in a mixer-settler liquid-liquid extraction column (A) Comprises of thin bed of substances of extended surface having high porosity (B) Helps in increasing the bubble size entering the settler ... increasing the settling rate of the bubbles (D) All 'a', 'b', & 'c'
Last Answer : (D) All 'a', 'b', & 'c'
Description : The sensitivity of a bubble tube can be increased by (A) Increasing the diameter of the tube (B) Decreasing the length of bubble (C) Increasing the viscosity of liquid (D) Decreasing the radius of curvature of tube
Last Answer : (A) Increasing the diameter of the tube
Description : Pick out the wrong statement about nucleate boiling. (A) Bubble generation is by expansion of entrapped gas/vapour at small cavities in the surface (B) Surface temperature is greater than the saturation ... less than that in film boiling (D) The temperature is less than that of film boiling
Last Answer : (D) The temperature is less than that of film boiling
Description : At the critical point of a substance (A) The surface tension vanishes (B) Liquid and vapour have the same density (C) There is no distinction between liquid and vapour phases (D) All (A), (B) and (C)
Description : Which one is the rate controlling step in a solid-gas non-catalytic reaction occurring at very high temperature? (A) Pore diffusion (B) Film diffusion (C) Ash layer diffusion (D) Chemical reaction
Last Answer : (B) Film diffusion
Description : If a solid-gas non-catalytic reaction occurs at very high temperature, the rate controlling step is the __________ diffusion. (A) Film (B) Ash layer (C) Pore (D) None of these
Last Answer : (A) Film
Description : How do viscosity and surface tension change as temperature increases?
Last Answer : Feel Free to Answer
Description : Capillary action is due to the (A) Surface tension (B) Cohesion of the liquid (C) Adhesion of the liquid molecules and the molecules on the surface of a solid (D) All of the above