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Mechanical Engineering :: Hydraulics and Fluid Mechanics

  1. Coefficient of resistance is the ratio of

  2. A.

     Actual velocity of jet at vena-contracta to the theoretical velocity

    B.

     Area of jet at vena-contracta to the area of orifice

    C.

     Loss of head in the orifice to the head of water available at the exit of the orifice

    D.

     Actual discharge through an orifice to the theoretical discharge


  3. The mercury does not wet the glass. This is due to the property of the liquid known as

  4. A.

     Cohesion

    B.

     Adhesion

    C.

     Viscosity

    D.

     Surface tension


  5. The total pressure on a horizontally immersed surface is (where w = Specific weight of the liquid, A = Area of the immersed surface, and x = Depth of the centre of gravity of the immersed surface from the liquid surface)

  6. A.

     wA

    B.

     wx

    C.

     wAx

    D.

     wA/x


  7. The depth of centre of pressure (h) for a vertically immersed surface from the liquid surface is given by (where IG = Moment of inertia of the immersed surface about horizontal axis through its centre of gravity, A = Area of immersed surface, and x = Depth of centre of gravity of the immersed surface from the liquid surface)

  8. A.

     (IG/Ax̅) - x̅

    B.

     (IG/x̅) - Ax̅

    C.

     (Ax̅/IG) + x̅

    D.

     (IG/Ax̅) + x̅


  9. A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. The total pressure on the wall acts at a distance __________ from the liquid surface.

  10. A.

     H/3

    B.

     H/2

    C.

     2H/3

    D.

     3H/4


  11. The discharge through a wholly drowned orifice is given by (where H1 = Height of water (on the upstream side) above the top of the orifice, H2 = Height of water (on the downstream side) above the bottom of the orifice, and H = Difference between two water levels on either side of the orifice)

  12. A.

     Q = Cd × bH₁ × √(2gh)

    B.

     Q = Cd × bH2 × √(2gh)

    C.

     Q = Cd × b (H2 - H1) × √(2gh)

    D.

     Q = Cd × bH × √(2gh)


  13. The discharge through a small rectangular orifice is given by (where Cd = Coefficient of discharge for the orifice, a = Cross-sectional area of the orifice, h = Height of the liquid above the centre of the orifice)

  14. A.

     Q = Cd × a × 2gh

    B.

     Q = (2/3). Cd × a × h

    C.

     Q = (Cd × a)/√(2gh)

    D.

     Q = (3Cd × a)/√(2h)


  15. One cubic metre of water weighs

  16. A.

     100 liters

    B.

     250 liters

    C.

     500 liters

    D.

     1000 liters


  17. According to fan laws, for fans having constant wheel diameter, the pressure varies

  18. A.

     Directly as fan speed

    B.

     Square of fan speed

    C.

     Cube of fan speed

    D.

     Square root of fan speed


  19. A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used?

  20. A.

     Pelton wheel with one nozzle

    B.

     Pelton wheel with two or more nozzles

    C.

     Kaplan turbine

    D.

     Francis turbine