51. When the cross-section of a nozzle increases continuously from entrance to exit, it is called a
divergent nozzle
convergent nozzle
convergent-divergent nozzle
none of these
✅ The correct answer is option A.
Steam Nozzles and Turbines MCQs
52. In an ideal impulse turbine, the
absolute velocity at the inlet of moving blade is equal to that at the outlet
relative velocity at the inlet of the moving blade is equal to that at the outlet
axial velocity at inlet is equal to that at the outlet
whirl velocity at inle
✅ The correct answer is option B.
53. If the critical pressure ratio for steam is 0.546, then the steam is initially
wet steam
dry saturated steam
superheated steam
none of these
✅ The correct answer is option C.
54. In a nozzle, the effect of supersaturation is to
decrease dryness fraction of steam
decrease specific volume of steam
increase the entropy
increase the heat drop
✅ The correct answer is option C.
55. The Rankine efficiency depends upon total useful heat drop and total isentropic heat drop.
Correct
Incorrect
✅ The correct answer is option B.
56. The maximum discharge of steam through a convergent-divergent nozzle depends upon
area of nozzle at throat
initial pressure and volume of steam
final pressure ofsteam leaving the nozzle
both (a) and (b)
✅ The correct answer is option D.
57. The effect of bleeding is that
it increases the thermodynamic efficiency of the turbine
boiler is supplied with hot water
it decreases the power developed by the turbine
all of the above
✅ The correct answer is option D.
58. A nozzle is said to be a divergent nozzle
when the cross-section of the nozzle increases continuously from entrance to exit
when the cross-section of the nozzle decreases continuously from entrance to exit
when the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit
none of the above
✅ The correct answer is option A.
59. The pressure of steam __________ while flowing through a nozzle.
increases
decreases
remains constant
✅ The correct answer is option B.
60. In turbines, the fluid undergoes a continuous steady flow process and the speed of flow is
low
very low
high
very high
✅ The correct answer is option D.