Hydraulic Turbines and Jets MCQ

101. The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which?

  1. Delivers unit discharge under unit head
  2. Delivers unit discharge under unit speed
  3. Develops unit power under unit head
  4. Develops unit power under unit speed
Answer
Answer. c

102. To avoid cavitation in reaction turbine

  1. the minimum pressure in the passage of a flow should always be more than the vapour pressure of the water at the working temperature
  2. the velocity should be high
  3. the discharge should be constant
  4. the speed of turbine should be less that runaway speed
Answer
Answer. a

103. In an inward flow reaction turbine, velocity of flow at the inlet is 2 m/s. If the guide vanes make an angle of 30° to the tangential velocity direction of the runner, the absolute velocity of the water leaving the guide vanes is

  1. 1 m/s
  2. 2 m/s
  3. 3 m/s
  4. 4 m/s
Answer
Answer. d

104. Cavitation will take place if the pressure of the following fluid at any points is

  1. more than vapour pressure of the fluid
  2. less than vapour pressure of the fluid
  3. equal to vapour pressure of the fluid
  4. none of the above
Answer
Answer. b

105. Maximum efficiency of power transmission through pipe is

  1. 66.67%
  2. 50%
  3. 75%
  4. 100%
Answer
Answer. a

106. A Pelton wheel with single jet rotates at 300rpm. The velocity of the jet from the nozzle is 100 m/s. If the ratio of the vane velocity to jet velocity is 0.44, what is the diameter of the Pelton wheel?

  1. 2.8 m
  2. 1.4 m
  3. 0.7 m
  4. 2.1 m
Answer
Answer. a

107. When a steady two-dimensional jet of water impinges on a stationary inclined plate and if the fluid friction is neglected, the resultant force on the plate is

  1. tangential to the surface.
  2. normal to the surface.
  3. in the direction of jet flow.
  4. normal to the direction of jet flow.
Answer
Answer. b

108. A nozzle directs a liquid jet at an angle of elevation of 45°. The hydraulic grade line for the jet

  1. will be horizontal with the centre line of jet.
  2. will be horizontal at the level of energy line.
  3. coincides with the centre line of the jet.
  4. coincides with the energy line.
Answer
Answer. c

109. In all reaction turbines, maximum efficiency is obtained if

  1. the guide vane angle is 90°
  2. the blade angle of the runners is 90° at the inlet
  3. the blade angle of the runners is 90° at the outlet
  4. the angle of the absolute velocity vector at the outlet is 90°
Answer
Answer. d

110. A water turbine of expected efficiency 85% operates under 36 m at a flow rate of 10 m3/s. The unit weight of water is 10 kN/m3. The nearest shaft power in MW is

  1. 3060
  2. 3.06
  3. 850
  4. 3600
Answer
Answer. b
Pages: 1 2 3 4 5 6 7 8 9 10 11