121. The efficiency of reaction turbine is maximum when (where α = Angle made by the absolute velocity (V) at inlet)
[A]. Vb = 0.5 V cos α
[B]. Vb = V cos α
[C]. Vb = 0.5 V2 cos α
[D]. Vb = V2 cos α
✅ The correct answer is option B.
Steam Nozzles and Turbines MCQs
122. The critical pressure gives the velocity of steam at the throat
[A]. equal to the velocity of sound
[B]. less than the velocity of sound
[C]. more than the velocity of sound
[D]. none of these
✅ The correct answer is option A.
123. The turbine, in which the general direction of the steam flow is parallel to the turbine axis, is called axial flow turbines
[A]. True
[B]. False
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✅ The correct answer is option A.
124. In a nozzle, whole frictional loss is assumed to occur between
[A]. inlet and thoroat
[B]. inlet and outlet
[C]. throat and exit
[D]. all of these
✅ The correct answer is option C.
125. In a convergent divergent nozzle, the discharge depends upon the initial conditions of steam and the area of nozzle at throat.
[A]. Correct
[B]. Incorrect
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✅ The correct answer is option A.
126. The ratio of the useful heat drop to the isentropic heat drop is called
[A]. condenser efficiency
[B]. nozzle efficiency
[C]. boiler efficiency
[D]. vacuum efficiency
✅ The correct answer is option B.
127. Parson’s reaction turbine is a __________ reaction turbine.
[A]. 40 percent
[B]. 50 percent
[C]. 60 percent
[D]. 70 percent
✅ The correct answer is option B.
128. The turbine blades are
[A]. straight
[B]. circular
[C]. curved
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✅ The correct answer is option C.
129. The maximum efficiency of a reaction turbine is
[A].
[B].
[C].
[D].
✅ The correct answer is option B.
130. A regenerative steam cycle renders
[A]. increased work output per unit mass of steam
[B]. decreased work output per unit mass of steam
[C]. increased thermal efficiency
[D]. decreased work output per unit mass of steam as well as increased thermal efficiency
✅ The correct answer is option D.