71. The velocity of steam at throat of the nozzle is __________ the velocity of sound.
equal to
less than
more than
✅ The correct answer is option A.
Steam Nozzles and Turbines MCQs
72. In a single stage impulse turbine, the velocity of steam approaching nozzles is negligible.
TRUE
FALSE
✅ The correct answer is option A.
73. The effect of friction in the nozzle __________ dryness fraction of steam.
has no effect on
decreases
increases
✅ The correct answer is option C.
74. Blading efficiency is also known as
stage efficiency
diagram efficiency
nozzle efficiency
none of these
✅ The correct answer is option B.
75. When the nozzle operates with the maximum mass flow, the nozzle is said to be
choked
underdamping
overdamping
none of these
✅ The correct answer is option A.
76. In a velocity compounded impulse turbine, when steam flows through the second row of moving blades,
velocity increases
velocity decreases
velocity remains constant
pressure remains const
✅ The correct answer is option B.
77. In a reaction turbine, when steam flows through the moving blades,
pressure increases while velocity decreases
pressure decreases while velocity increases
pressure and velocity both decreases
pressure and velocity
✅ The correct answer is option C.
78. The diagram efficiency is the ratio of
workdone on the blades to the energy supplied to the blades
workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam
energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam
none of the above
✅ The correct answer is option A.
79. Stage efficiency is also known as
diagram efficiency
nozzle efficiency
gross efficiency
none of these
✅ The correct answer is option C.
80. In an impulse turbine
the steam is expanded in nozzles only and there is a pressure drop and heat drop
the steam is expanded both in fixed and moving blades continuously
the steam is expanded in moving blades only
the pressure and tempe
✅ The correct answer is option A.