Viscosity of water is about _____________ times that of air at room temperature?

Related Mcqs:

1. A Rotameter through which air at room temperature and atmospheric pressure is flowing gives a certain reading for a flow rate of 100 cc/sec. If helium (molecular weight 4) is used and Rotameter shows the same reading, the flow rate (cc/sec) is__________________?

   A. 26
   B. 42
   C. 269
   D. 325

2. A lubricant 100 times more viscous than water would have a viscosity (in Pa.s) ?

   A. 0.01
   B. 0.1
   C. 1
   D. 10

3. As per Newton’s law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to (where, μ = fluid viscosity) ?

   A. 1/μ
   B. μ
   C. μ2
   D. 1/μ2

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 flow of water at room temperature through 2 cm dia pipe at an average velocity of 5 cm/sec is around________________?

   A. 2000
   B. 10
   C. 100
   D. 1000

6. What is the force required (in Newtons) to hold a spherical balloon stationary in water at a depth of H from the air-water interface? The balloon is of radius 0.1 m and is filled with air ?

   A. 4πg/3
   B. 0.01 πgH/4
   C. 0.01 πgH/8
   D. 0.04 πgH/3

7. The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of the following order of magnitude (assume size of the bacterium to be 1 micron and kinematic viscosity of water to be 10-6m2/s) ?

   A. 24000
   B. 24
   C. 0.24
   D. 0.44

8. With increase in the temperature, viscosity of a liquid____________________?

   A. Increases
   B. Decreases
   C. Remain constant
   D. May increase or decrease; depends on the liquid

9. A Pitot tube indicates 5 cm of water (manometer) when it is being used for measuring velocity of air. The velocity of air in m/sec is___________________?

   A. 5
   B. 14.1
   C. 56.22
   D. 28.2

10. 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