The flames and hot gases pass through the tubes which are surrounded by water

Water passes through the tubes which are surrounded by flames and hot gases

Practice Steam Boilers, Engines, Nozzles And Turbines Multiple Choice Questions Quiz-11

Q.1

Pick up the wrong statement about water tube boiler in comparison to fire tube boilers

Former occupies less space for same power
Rate of steam flow is more in former case
Former is used for high installed capacity
Chances of explosion are less in former case

Q.2

The high steam and low water safety valve is used to blow off steam when the

Steam pressure exceeds the working pressure
Water level in the boiler becomes too low
Both (A) and (B)
None of the above

Q.3

In a boiler, feed water supplied per hour is 205 kg while coal fired per hour is 23 kg. The net enthalpy rise per kg of water is 145 kJ. If the calorific valve of the coal is 2050 kJ/kg, then the boiler efficiency will be

56 %
63 %
74 %
78 %

Q.4

In fire tube boilers

Water passes through the tubes which are surrounded by flames and hot gases
The flames and hot gases pass through the tubes which are surrounded by water
Forced circulation takes place
None of these

Q.5

Steam turbines may be classified according to

Direction of steam flow
Number of stages
Mode of steam action
All of these

Q.6

In order to reduce the rotor speed of an impulse turbine, the method employed is

Velocity compounding
Pressure compounding
Pressure-velocity compounding
All of these

Q.7

The velocity of flue gases (V) through the chimney under a static draught of (H') metres is given by

V = 2g H'
V = 2g/H'
V = H'/2g
V = 2gH'

Q.8

The function of a piston rod is

To guide motion of the piston rod and to prevent it from bending
To transfer motion from the piston to the cross head
To convert heat energy of the steam into mechanical work
To exhaust steam from the cylinder at proper moment

Q.9

For burning 1 kg of carbon to CO as per chemically correct combustion, amount of air required is

1 kg
4/3 kg
8/3 kg
2 kg

Q.10

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

Q.11

The ratio of the temperature rise of cooling water to the vacuum temperature minus inlet cooling water temperature is called

Condenser efficiency
Vacuum efficiency
Nozzle efficiency
Boiler efficiency

Q.12

Lancashire boiler has __________ internal flue tubes.

One
Two
Three
Four

Q.13

Pick up wrong statement about desired properties of a good fuel

High calorific value
Produce minimum smoke and gases
Ease in storing
High ignition point

Q.14

Spontaneous combustion is a phenomenon in which

All the fuel burns instantaneously producing high energy release
Fuel burns with less air
Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal
Explosion in furnace

Q.15

Which of the following statement is correct?

The expansion of steam in a nozzle follows Rankine cycle
The friction in the nozzle increases the dryness fraction of steam
The pressure of steam at throat is called critical pressure
All of the above

Q.16

Which of the following statement is correct?

A horizontal steam engine requires less floor area than a vertical steam engine
The steam pressure in the cylinder is not allowed to fall below the atmospheric pressure
The compound steam engines are generally non-condensing steam engines
All of the above

Q.17

For a Parson's reaction turbine, if α₁ and α₂ are fixed blade angles at inlet and exit respectively and β₁ and β₂ are the moving blade angles at entrance and exit respectively, then

α₁ = α₂ and β₁ = β₂
α₁ = β₁ and α₂= β₂
α₁ < β₁ and α₂ > β₂
α₁ = β₂ and β₁ = α₂

Q.18

A device used to increase the temperature of saturated steam without raising its pressure, is called

Blow off cock
Fusible plug
Superheater
Stop valve

Q.19

If partial pressure of air and steam be ‘pa’ and ‘ps’ respectively in a condenser, then according to Dalton's law, the pressure in condenser is equal to

ps - pa
pa - ps
pa + ps
None of these

Q.20

The actual vacuum in a condenser is equal to

Barometric pressure + actual pressure
Barometric pressure - actual pressure
Gauge pressure + atmospheric pressure
Gauge pressure - atmospheric pressure

Q.21

In a steam condenser, the partial pressure of steam and air are 0.06 bar and 0.007 bar respectively. The condenser pressure is

0.007 bar
0.053 bar
0.06 bar
0.067 bar

Q.22

Which of the following statement is correct?

Lancashire boiler is a fire tube boiler
Fire tube boilers are internally fired
Babcock and Wilcox boiler is a water tube boiler
All of the above

Q.23

Which of the following statement is correct?

A fire tube boiler occupies less space than a water tube boiler, for a given power
Steam at a high pressure and in large quantities can be produced with a simple vertical boiler
A simple vertical boiler has one fire tube
All of the above

Q.24

The change in internal energy in steam engines equals to

Work done during the Rankine cycle
Work done during compression
Work done during adiabatic expansion
Change in enthalpy

Q.25

The velocity of steam at throat of the nozzle is __________ the velocity of sound.

Equal to
Less than
More than
None of these

Q.26

The friction in the nozzle __________ exit velocity of steam.

Has no effect on
Decreases
Increases
None of these

Q.27

For water, at pressures below atmospheric;

Melting point rises slightly and boiling point drops markedly
Melting point rises markedly and boiling point drops markedly
Melting point drops slightly and boiling point drops markedly
Melting point drops slightly and boiling point drops slightly

Q.28

The condition of steam in boiler drum is always

Dry
Wet
Saturated
Supersaturated

Q.29

The critical pressure gives the velocity of steam at the throat

Equal to the velocity of sound
Less than the velocity of sound
More than the velocity of sound
None of these

Q.30

A regenerative steam cycle renders

Increased work output per unit mass of steam
Decreased work output per unit mass of steam
Increased thermal efficiency
Decreased work output per unit mass of steam as well as increased thermal efficiency

Pick up the wrong statement about water tube boiler in comparison to fire tube boilers

The high steam and low water safety valve is used to blow off steam when the

In a boiler, feed water supplied per hour is 205 kg while coal fired per hour is 23 kg. The net enthalpy rise per kg of water is 145 kJ. If the calorific valve of the coal is 2050 kJ/kg, then the boiler efficiency will be

In fire tube boilers

Steam turbines may be classified according to

In order to reduce the rotor speed of an impulse turbine, the method employed is

The velocity of flue gases (V) through the chimney under a static draught of (H') metres is given by

The function of a piston rod is

For burning 1 kg of carbon to CO as per chemically correct combustion, amount of air required is

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

The ratio of the temperature rise of cooling water to the vacuum temperature minus inlet cooling water temperature is called

Lancashire boiler has __________ internal flue tubes.

Pick up wrong statement about desired properties of a good fuel

Spontaneous combustion is a phenomenon in which

Which of the following statement is correct?

Which of the following statement is correct?

For a Parson's reaction turbine, if α₁ and α₂ are fixed blade angles at inlet and exit respectively and β₁ and β₂ are the moving blade angles at entrance and exit respectively, then

A device used to increase the temperature of saturated steam without raising its pressure, is called

If partial pressure of air and steam be ‘pa’ and ‘ps’ respectively in a condenser, then according to Dalton's law, the pressure in condenser is equal to

The actual vacuum in a condenser is equal to

In a steam condenser, the partial pressure of steam and air are 0.06 bar and 0.007 bar respectively. The condenser pressure is

Which of the following statement is correct?

Which of the following statement is correct?

The change in internal energy in steam engines equals to

The velocity of steam at throat of the nozzle is __________ the velocity of sound.

The friction in the nozzle __________ exit velocity of steam.

For water, at pressures below atmospheric;

The condition of steam in boiler drum is always

The critical pressure gives the velocity of steam at the throat

A regenerative steam cycle renders

0 h : 0 m : 1 s

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