# Engineering :: Hydraulics Machines

1.  A jet of water is striking at the centre of a curved vane moving with a uniform velocity in the direction of jet. For the maximum efficiency, the vane velocity is
 A. one-half B. one-third C. two-third D. three-fourth

2.  The principle of jet propulsion is used in driving the ships and aeroplanes.
 A. Correct B. Incorrect

3.  A jet of water enters and leaves a fixed curved vane tangentially. The force of jet along perpendicular to the vane is zero.
 A. True B. False

4.  The efficiency of jet propulsion for a ship with inlet orifices at right angles to the direction of motion of ship, will be maximum when the relative velocity of the jet and ship is equal to twice the velocity of the ship.
 A. Yes B. No

5.  The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, is
 A. 40% B. 50% C. 60% D. 80%

6.  The undershot water wheels are those in which
 A. the wheel runs entirely by the weight of water B. the wheel runs entirely by the impulse of water C. the wheel runs partly by the weight of water and partly by the impulse of water D. none of the above

7.  The breast water wheels are those in which the wheel runs partly by the weight of water and partly by the impulse of water.
 A. True B. False

8.  The overshot water wheels are those in which the wheel runs entirely by the
 A. weight B. impulse

9.  Which of the following statement is correct as regard to water wheels?
 A. They have slow speeds. B. They are suitable even for low water heads C. They give constant efficiency, even if the discharge is not constant. D. all of the above

10.  Braking jet in an impulse turbine is used
 A. to break the jet of water B. to bring the runner to rest in a short time C. to change the direction of runner D. none of the above