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  • Question
  • If Hg is the gross or total head and hf is the head lost due to friction, then net or effective head (H) is given by


  • Options
  • A. H = Hg/hf
  • B. H = Hg x hf
  • C. H = Hg + hf
  • D. H = Hg - hf

  • Correct Answer
  • H = Hg - hf 


  • Hydraulic Machines problems


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    • 1. The overall efficiency of a reaction turbine is the ratio of

    • Options
    • A. power produced by the turbine to the energy actually supplied by the turbine
    • B. actual work available at the turbine to the energy imparted to the wheel
    • C. workdone on the wheel to the energy (or head of water) actually supplied to the turbine
    • D. none of the above
    • Discuss
    • 2. The overshot water wheels are those in which the wheel runs entirely by the __________ of water.

    • Options
    • A. weight
    • B. impulse
    • Discuss
    • 3. The mechanical efficiency of an impulse turbine is

    • Options
    • A. ratio of the actual power produced by the turbine to the energy actually supplied by the turbine
    • B. ratio of the actual work available at the turbine to the energy imparted to the wheel
    • C. ratio of the Work done on the wheel to the energy of the jet
    • D. none of the above
    • Discuss
    • 4. The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as

    • Options
    • A. normal speed
    • B. unit speed
    • C. specific speed
    • D. none of these
    • Discuss
    • 5. The power produced by the reaction turbine is __________ to the head of water.

    • Options
    • A. directly proportional
    • B. inversely proportional
    • Discuss
    • 6. The efficiency of a centrifugal pump will be maximum when the blades are bent backward.

    • Options
    • A. Yes
    • B. No
    • Discuss
    • 7. In a reaction turbine, the draft tube is used

    • Options
    • A. to run the turbine full
    • B. to prevent air to enter the turbine
    • C. to increase the head of water by an amount equal to the height of the runner outlet above the tail race
    • D. to transport water to downstream
    • Discuss
    • 8. The capacity of a hydraulic accumulator is generally specified as the maximum amount of energy stored.

    • Options
    • A. True
    • B. False
    • Discuss
    • 9. In a reciprocating pump, air vessels are fitted to the suction pipe and delivery pipe close to the cylinder of the pump.

    • Options
    • A. True
    • B. False
    • Discuss
    • 10. Multi-stage centrifugal pumps are used to

    • Options
    • A. give high discharge
    • B. produce high heads
    • C. pump viscous fluids
    • D. all of these
    • Discuss


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