A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke’s law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity ?

Related Mcqs:

1. Brownian movement is prominent in the particle size range of _____________ microns in case of settling of a particle in a fluid?

   A. 2 to 3
   B. 0.01 to 0.10
   C. 200 to 300
   D. 100 to 1000

2. For a particle settling in water at its terminal settling velocity, which of the following is true ?

   A. Buoyancy = weight + drag
   B. Weight = buoyancy + drag
   C. Drag = buoyancy + weight
   D. Drag = weight

3. A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun’s equation for the above fluid-particle system (in SI units) is given below : Δ P/L = 375 × 103 VOM + 10.94 × 106 V2 OM (SI units) If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is_________________?

   A. 12 mm/s
   B. 16 mm/s
   C. 24 mm/s
   D. 28 mm/s

4. A gas (density = 1.5 kg/m3, viscosity = 2 × 10‒5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The pressure drop for another gas, with density of 1.5 kg/m3and viscosity of 3 × 10‒5kg/m.s flowing at 3 m/s will be________________?

   A. 8400 Pa/m
   B. 12600 Pa/m
   C. 18900 Pa/m
   D. 16800 Pa/m

5. Reynolds number for water flow through a tube of I.D. 5 cm is 1500. If a liquid of 5 centipoise viscosity and 0.8 specific gravity flows in the same pipe at the same velocity, then the pressure drop will______________________?

   A. Increase
   B. Decrease
   C. Remain same
   D. Data insufficient to predict pressure drop

6. A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun’s equation for the above fluid-particle system (in SI units) is given below: Δ P/L = 375 × 103 VOM + 10.94 × 106 V2 OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ?

   A. 0.2
   B. 0.5
   C. 0.7
   D. 0.8

7. In the Newton’s law range, the terminal velocity of a solid spherical particle falling through a stationary fluid mass is ______________ the fluid viscosity?

   A. Directly proportional to
   B. Inversely proportional to
   C. Inversely proportional to the square root of
   D. Independent of

8. A mercury (specific gravity = 13.6) manometer connected across an orificemeter fitted in a pipe shows a manometer reading of 2 cms. If the manometer liquid is changed to carbon tetrachloride (specific gravity = 1.6), then for the same flow rate of water the new manometer reading will be _______________ cms?

   A. 17
   B. 42
   C. 84
   D. 1.8

9. Hydrometer measures the specific gravity of liquids based on the principles of buoyancy. Pycnometer is used to measure the specific gravity of_________________?

   A. Powder & granular solids
   B. Liquids
   C. Low melting point semi-solids
   D. All A, B & C

10. One poise (unit of absolute/dynamic viscosity) is equivalent to one_____________________?

    A. gm/cm2. sec
    B. gm/cm. sec
    C. cm2/sec
    D. m2/sec