Power Plant Engineering (2171910) MCQs

MCQs of Steam Turbine

Showing 21 to 30 out of 61 Questions
21.

In a reaction turbine, when steam flows through the fixed blades

(a)

pressure increases while velocity decreases

(b)

pressure decreases while velocity increases

(c)

pressure and velocity both decreases

(d)

pressure and velocity both increases

Answer:

Option (b)

22.

In a reaction turbine, when steam flows through the moving blades

(a)

pressure increases while velocity decreases

(b)

pressure decreases while velocity increases

(c)

pressure and velocity both decreases

(d)

pressure and velocity both increases

Answer:

Option (c)

23.

In an impulse reaction turbine, the pressure drops gradually and continuously over

(a)

fixed blades

(b)

moving blades

(c)

both fixed and moving blades

(d)

none of these

Answer:

Option (c)

24.

The maximum efficiency in impulse steam turbine is

(a)

2Cosα

(b)

Cos2α

(c)

Cos(α/2)

(d)

Cos2α

Answer:

Option (d)

25.

The maximum efficiency in reaction steam turbine is

(a)

2 sin²α/(1 + sin²α)

(b)

2 cos²α/(1 + cos²α)

(c)

(1 + sin²α)/2 sin²α

(d)

(1 + cos²α)/2 cos²α

Answer:

Option (b)

26.

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

Answer:

Option (b)

27.

De-Laval turbine is a

(a)

single rotor impulse turbine

(b)

multi-rotor impulse turbine

(c)

impulse reaction turbine

(d)

none of these

Answer:

Option (a)

28.

In an ideal impulse turbine, the

(a)

absolute velocity at the inlet of moving blade is equal to that at the outlet

(b)

relative velocity at the inlet of the moving blade is equal to that at the outlet

(c)

axial velocity at inlet is equal to that at the outlet

(d)

whirl velocity at inlet is equal to that at the outlet

Answer:

Option (b)

29.

De-Laval turbines are mostly used

(a)

where low speeds are required

(b)

for small power purposes and low speeds

(c)

for large power purposes

(d)

for small power purposes and high speeds

Answer:

Option (d)

30.

Rateau turbine is

(a)

simple reaction turbine

(b)

velocity compounded turbine

(c)

pressure compounded turbine

(d)

pressure-velocity compounded turbine

Answer:

Option (c)

Showing 21 to 30 out of 61 Questions