1. When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be ?

choked

underdamping

overdamping

none of these

Answer: underdamping

Explanation:


2. The ratio of the work done on the blades per kg of steam to the total energy supplied per stage per kg of steam is called ?

blading efficiency

nozzle efficiency

stage efficiency

mechanical efficiency

Answer: stage efficiency

Explanation:


3. In turbines, the fluid undergoes a continuous steady flow process and the speed of flow is ?

low

very low

high

very high

Answer: very high

Explanation:


4. In a reaction turbine ?

the steam is allowed to expand in the nozzle, where it gives a high velocity before it enters the moving blades

the expansion of steam takes place partly in the fixed blades and partly in the moving blades

the steam is expanded from a high pressure to a condenser pressure in one or more nozzles

the pressure and temperature of steam remains constant

Answer: the expansion of steam takes place partly in the fixed blades and partly in the moving blades

Explanation:


5. The compounding of turbines is done in order to ?

reduce speed of rotor

improve efficiency

reduce exit losses

all of these

Answer: all of these

Explanation:


6. Which of the following statement is correct ?

The efficiency of steam turbines is greater than steam engines

A flywheel is a must for steam turbine

The turbine blades do not change the direction of steam issuing from the nozzle

The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades

Answer: The efficiency of steam turbines is greater than steam engines

Explanation:


7. In an impulse turbine, steam expands ?

wholly in blades

wholly in nozzle

partly in the nozzle and partly in blades

none of these

Answer: wholly in nozzle

Explanation:


8. De-Laval turbines are mostly used ?

where low speeds are required

for small power purposes and low speeds

for large power purposes

for small power purposes and high speeds

Answer: for small power purposes and high speeds

Explanation:


9. The flow of steam is super-sonic ?

at the entrance to the nozzle

at the throat of the nozzle

in the convergent portion of the nozzle

in the divergent portion of the nozzle

Answer: in the divergent portion of the nozzle

Explanation:


10. A stag in reaction turbine, is represented by ?

number of casing

number of entries of steam

number of exits of steam

each row of blades

Answer: each row of blades

Explanation: