NOZZLES MULTIPLE CHOICE QUESTIONS (MCQ) WITH ANSWERS
NOZZLES MULTIPLE
CHOICE QUESTIONS
(MCQ) WITH ANSWERS
MCQ significantly increase the
understanding of the nozzle. More
MCQ will further increase the
knowledge about the nozzle. Nozzle
converts pressure energy into kinetic
energy. Nozzles are convergent,
divergent and convergent-divergent
types. There is velocity increase and
pressure decrease in a convergent nozzle.
There is velocity decrease and pressure
increase in a divergent nozzle.
1. The critical pressure ratio for initially wet steam across a steam nozzle is
-
546
-
582
-
578
-
None
Ans: (ii)
2. The critical pressure ratio for initially super-heated steam across a steam nozzle is
-
582
-
546
-
578
-
None
Ans: (ii)
3. The efficiency of the nozzle is
-
Actual enthalpy drop/Isotropic enthalpy drop
-
Isobaric enthalpy drop/Isotropic enthalpy drop
-
Iso-thermal enthalpy drop/Isotropic enthalpy drop
-
None
Ans: (i)
4. Velocity coefficient in a steam nozzle is
-
(Iso-thermal enthalpy drop/Isotropic enthalpy drop)5
-
(Actual enthalpy drop/Isotropic enthalpy drop)5
-
(Isobaric enthalpy drop/Isotropic enthalpy drop)5
-
None
Ans: (ii )
5. Theoretical velocity at the exit of the nozzle will be
-
Exit velocity c2 = 44.42 (h1-h2)0.5
-
Velocity at exit c2 = 44.92 (h1-h2)0.5
-
c2 = 44.72 (h1-h2)0.5
-
None
Ans: (iii )
6. The critical pressure ratio in a steam nozzle is equal to
-
[(γ+1)/2](γ/(γ+1))
-
[(2/(γ+1)] (γ/(γ+1))
-
[(2/(γ+1)] ((γ+1)/γ)
-
None
Ans: (ii)
7. The equation for the shape of a nozzle is
-
Ratio dA/A =(dc/c)[M2 –1)
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dA/A =(dc/c)[1–M2)
-
dA/A =(dc/c)[M2 +1)
-
None
Ans: (i)
-
The velocity in a nozzle, When M = 1
-
Minimum
-
Maximum
-
Neither minimum nor maximum
-
None
Ans: (ii)
-
When M = 1 the area of the nozzle be
-
Minimum
-
Maximum
-
Neither minimum nor maximum
-
None
Ans: (i)
-
Using equation dA/A =(dc/c)[M2 –1) for a nozzle, when M<1 . Velocity in the nozzle will increase if the area of the nozzle
-
Decreases
-
Increases
-
Constant
-
(d) None
Ans:(i)
-
With respect to equation dA/A =(dc/c)[M2 –1) for a nozzle, when M<1 . Velocity in the nozzle will decrease if the area of the nozzle
-
Constant
-
Increases
-
Decreases
-
None
Ans:(ii)
-
Using equation dA/A =(dc/c)[M2 –1) for a nozzle, when M>1 , velocity in the nozzle will increase if the area of the nozzle
-
Increases
-
Decreases
-
Constant
-
None
Ans:(i)
-
Nozzle equation dA/A =(dc/c)[M2 –1), when M>1 , velocity in the nozzle will decrease if the area of the nozzle
-
Decreases
-
Increases
-
Constant
-
None
Ans:(i)
-
Stagnation properties are used when the value of M is
-
<0.1
-
<0.4
-
>0.4
-
None
Ans: (iii)
-
Efficiency of a nozzle vs efficiency of a diffuser is
-
Less
-
Equal
-
More
-
None
Ans: (iii)
-
A nozzle is said to be choking under
-
Minimum flow rate
-
Maximum flow rate
-
Neither maximum nor minimum flow rate
-
None
Ans: (ii)
17. Velocity of steam in the divergent portion of the nozzle
-
Remains constant
-
Increases
-
Decreases
-
None
Ans: (ii)
-
There is more friction in the
-
convergent portion
-
Divergent portion
-
At the throat
-
None
Ans: (ii)
-
A steam nozzle is said to be choked if
-
Steam flow through the nozzle decreases
-
Pressure at throat is less than the exit pressure
-
Pressure at throat is equal to the steam supply pressure
-
None
Ans: (iv)
-
Shock effect in a nozzle generally occurs in the
-
Convergent portion
-
At the exit
-
Divergent portion
-
None
Ans: (iii)
-
Which type of nozzle is used in a steam turbine
-
Convergent
-
Divergent
-
Convergent-divergent
-
None
Ans: (iii)
-
The velocity of steam at critical pressure at throat is
-
More than the sound velocity
-
Equal to the sound velocity
-
Less than the velocity of sound
-
None
Ans: (i)
-
Steam leaves the nozzle with
-
High pressure and high velocity
-
Low pressure and low velocity
-
High pressure and low velocity
-
None
Ans: (iv)
-
The condition of steam leaving the nozzle is
-
Low pressure and high velocity
-
Low pressure and low velocity
-
High pressure and low velocity
-
None
Ans: (i)
-
Total friction in the nozzle is between the
-
Inlet and exit
-
Inlet and throat
-
Throat and exit
-
None
Ans: (iii)
-
The action of steam turbine in the steam turbine is
-
Static
-
Dynamic
-
Static as well as dynamic
-
None
Ans: (ii)
27. Critical velocity in a nozzle is given by the relation
-
Critical velocity C* =(γRT*)5
-
C* =(RT*/γ)5
-
C* =(γR/T*)5
-
None