Rain drops falling through atmospheric air attain limited terminal velocity, because of ____________________?

Related Mcqs:

1. A particle is settling in a liquid under Stokesian conditions. The free falling velocity of the particle is proportional to____________________?

   A. √(Particle diameter)
   B. Particle diameter
   C. (Particle diameter)2
   D. (Particle diameter)3

2. A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is ________________ W/m2 °C ?

   A. 50
   B. 100
   C. 150
   D. 200

3. Air/fuel ratio by weight for combustion of methane with theoretical quantity of air will be about ____________________?

   A. 9 : 1
   B. 17 : 1
   C. 23 : 1
   D. 29 : 1

4. Saturated steam at a pressure of 25 kg/cm2 is throttled to attain 5 kg/cm2. Then the outcoming steam will be_________________?

   A. Wet
   B. Saturated
   C. Superheated
   D. None of these

5. Percentage of argon (by volume) in dry atmospheric air is about________________?

   A. 0.09
   B. 0.3
   C. 0.57
   D. 0.94

6. In Newton’s law of viscosity, which states that the shear stress is proportional to the _____________ Co-efficient of viscosity is called dynamic or absolute viscosity(where, V = velocity, Vg = velocity gradient) ?

   A. V2
   B. 1/V2
   C. 1/Vg
   D. Vg

7. For the Stoke’s law to be valid in the case of a falling sphere in a fluid, the_____________________?

   A. Reynolds number (based on sphere diameter) should be < 1
   B. Flow around the sphere should be in turbulent region
   C. Sphere must be metallic
   D. Fluid density should be constant

8. In case of condensers & evaporators operating under given terminal conditions, LMTD (logarithmic mean temperature difference) for counter flow as compared to that for parallel flow is__________________?

   A. More
   B. Less
   C. Equal
   D. Much more

9. Maximum permissible air velocity in pipelines is about ______________ metre/second ?

   A. 5
   B. 10
   C. 20
   D. 40

10. Air/fuel ratio on molar (volume) basis for combustion of methane with theoretical quantity of air with be________________?

    A. 9.5 : 1
    B. 12.5 : 1
    C. 15.5 : 1
    D. 18.5 : 1