4791 + Mcqs in Mechanical Engineering Page 67 McqOptions

3301.	The device attached to the steam chest for preventing explosions due to excessive internal pressure of steam is called
A.	safety valve
B.	water level indicator
C.	pressure gauge
D.	fusible plug
Answer» B. water level indicator

Discussion

3302.	In a steam engine, superheated steam from the boiler is fed into the steam chest at a pressure of
A.	10 atmospheres
B.	20 atmospheres
C.	30 atmospheres
D.	40 atmospheres
Answer» C. 30 atmospheres

Discussion

3303.	The pressure of feed water has to be raised before its entry into the boiler. The pressure is raised by a device known as
A.	feedpump
B.	injector
C.	feed check valve
D.	pressure gauge
Answer» B. injector

Discussion

3304.	Which of the following statement indicates the difference between Cornish boiler and Lancashire boiler ?
A.	Cornish boiler is a water tube boiler whereas Lancashire boiler is a fire tube boiler.
B.	Cornish boiler is a fire tube boiler whereas Lancashire boiler is a water tube boiler.
C.	Cornish boiler has one flue tube whereas Lancashire boiler has two flue tubes.
D.	Cornish boiler has two flue tubes whereas Lancashire boiler has one flue tube.
Answer» D. Cornish boiler has two flue tubes whereas Lancashire boiler has one flue tube.

Discussion

3305.	By compounding the expansion of steam in two or more cylinders, the ratio of expansion
A.	does not change
B.	increases
C.	decreases
Answer» D.

Discussion

3306.	The water tubes in a simple vertical boiler are
A.	horizontal
B.	vertical
C.	inclined
Answer» D.

Discussion

3307.	The ratio of heat actually used in producing the steam to the heat liberated in the furnace, is known as
A.	equivalent evaporation
B.	factor of evaporation
C.	boiler efficiency
D.	power of a boiler
Answer» D. power of a boiler

Discussion

3308.	A vessel into which the steam is exhausted and condensed after doing work in an engine cylinder or turbine is known as
A.	steam condenser
B.	steam boiler
C.	steam preheater
D.	economiser
Answer» B. steam boiler

Discussion

3309.	The value of diagram factor depends upon
A.	initial conditions of steam
B.	back pressure
C.	initial pressure of steam
D.	all of these
Answer» E.

Discussion

3310.	The function of an eccentric rod is
A.	to provide reciprocating motion to the slide valve
B.	to convert reciprocating motion of the piston into rotary motion of the crank
C.	to convert rotary motion of the crankshaft into to and fro motion of the valve rod
D.	to provide simple harmonic motion to the D-slide valve
Answer» D. to provide simple harmonic motion to the D-slide valve

Discussion

3311.	A receiver type compound engine, requires a lighter flywheel.
A.	Yes
B.	No
Answer» B. No

Discussion

3312.	The function of a valve rod is
A.	to provide reciprocating motion to the slide valve
B.	to convert reciprocating motion of the piston into rotary motion of the crank
C.	to convert rotary motion of the crankshaft into to and fro motion of the valve rod
D.	to provide simple harmonic motion to the D-slide valve
Answer» E.

Discussion

3313.	The principal function of a stop valve is to
A.	control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
B.	empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
C.	put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
D.	increase the temperature of saturated steam without raising its pressure
Answer» B. empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler

Discussion

3314.	The length of Cornish boiler varies from
A.	2 to 4.5 m
B.	3 to 5 m
C.	5 to 7.5 m
D.	7 to 9 m
Answer» D. 7 to 9 m

Discussion

3315.	The indicated thermal efficiency is defined as the
A.	ratio of thermal efficiency to the Rankine efficiency
B.	ratio of brake power to the indicated power
C.	ratio of heat equivalent to indicated power to the energy supplied in steam
D.	product of thermal efficiency and Rankine efficiency
Answer» D. product of thermal efficiency and Rankine efficiency

Discussion

3316.	In surface condensers, the condensate and the cooling water mixes up.
A.	True
B.	False
Answer» C.

Discussion

3317.	A water level indicator is a device to indicate the exact water level in the boiler at any instant.
A.	True
B.	False
Answer» B. False

Discussion

3318.	An economiser is generally placed between
A.	last superheater or reheater and air preheater
B.	induced draft fan and forced draft fan
C.	air preheater and chimney
D.	none of the above
Answer» B. induced draft fan and forced draft fan

Discussion

3319.	In fire tube boilers
A.	water passes through the tubes which are surrounded by flames and hot gases
B.	the flames and hot gases pass through the tubes which are surrounded by water
C.	forced circulation takes place
D.	none of these
Answer» C. forced circulation takes place

Discussion

3320.	The efficiency of a boiler is defined as
A.	ratio of heat actually used in producing steam to the heat liberated in the furnace
B.	ratio of the mass of steam produced to the mass of total water supplied in a given time
C.	ratio of the heat liberated in the furnace to the heat actually Used in producing steam
D.	none of the above
Answer» B. ratio of the mass of steam produced to the mass of total water supplied in a given time

Discussion

3321.	The ratio of the temperature rise of cooling water to the vacuum temperature minus inlet cooling water temperature is called
A.	condenser efficiency
B.	vacuum efficiency
C.	nozzle efficiency
D.	boiler efficiency
Answer» B. vacuum efficiency

Discussion

3322.	A valve installed between the boiler and the feed pump is
A.	blow off cock
B.	feed check valve
C.	steam stop valve
D.	none of these
Answer» C. steam stop valve

Discussion

3323.	A device used to empty the boiler whenever required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler, is called blow off cock.
A.	Yes
B.	No
Answer» B. No

Discussion

3324.	The ratio of the energy required to produce the artificial draught (expressed in metres head or J/kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to natural draught, is known as
A.	efficiency of the boiler
B.	efficiency of the chimney
C.	efficiency of the fan
D.	power of the boiler
Answer» C. efficiency of the fan

Discussion

3325.	The actual power generated in the engine cylinder is called
A.	indicated power
B.	brake power
C.	frictional power
D.	none of these
Answer» B. brake power

Discussion

3326.	The high steam and low water safety valve is not used in
A.	Cochran boiler
B.	Cornish boiler
C.	Lancashire boiler
D.	Locomotive boiler
Answer» E.

Discussion

3327.	The draught in locomotive boilers is produced by a
A.	chimney
B.	centrifugal fan
C.	steam jet
D.	none of these
Answer» D. none of these

Discussion

3328.	The ratio of heat actually used in producing the steam to the heat liberated in the furnace is known as equivalent evaporation from and at 100 C.
A.	Correct
B.	Incorrect
Answer» C.

Discussion

3329.	There is about 15 to 20% of coal saving when an economiser is used in a boiler.
A.	True
B.	False
Answer» B. False

Discussion

3330.	Clearance ratio is the ratio of
A.	clearance volume to the swept volume
B.	clearance volume to the volume at cut-off
C.	volume at cut-off to the swept volume
D.	swept volume to the clearance volume
Answer» B. clearance volume to the volume at cut-off

Discussion

3331.	In a boiler, the heat is lost
A.	to dry flue gases
B.	in moisture present in the fuel
C.	to steam formed by combustion of hydrogen per kg of fuel
D.	all of the above
Answer» E.

Discussion

3332.	For a beam, as shown in the below figure, the deflection at C is (where E = Young's modulus for the beam material, and I = Moment of inertia of the beam section. )
A.	<img src="/_files/images/mechanical-engineering/strength-of-materials/105-246-1.png">
B.	<img src="/_files/images/mechanical-engineering/strength-of-materials/105-245-1.png">
C.	<img src="/_files/images/mechanical-engineering/strength-of-materials/105-246-3.png">
D.	<img src="/_files/images/mechanical-engineering/strength-of-materials/105-246-4.png">
Answer» C. <img src="/_files/images/mechanical-engineering/strength-of-materials/105-246-3.png">

Discussion

3333.	The shear modulus of most materials with respect to the modulus of elasticity is
A.	equal to half
B.	less than half
C.	more than half
D.	none of these
Answer» C. more than half

Discussion

3334.	A watt's governor can work satisfactorily at speeds from
A.	60 to 80 r.p.m.
B.	80 to 100 r.p.m.
C.	100 to 200 r.p.m.
D.	200 to 300 r.p.m.
Answer» B. 80 to 100 r.p.m.

Discussion

3335.	The boiler efficiency is given by (where m = Total mass of water evaporated into steam in kg/h, mf = Mass of fuel in kg/h, C = Calorific valve of fuel in kJ/kg of fuel, h = Total heat of steam in kJ/kg, and hf1 = Sensible heat of feed water in kJ /kg)
A.	<img src="/_files/images/mechanical-engineering/steam-boilers-and-engines/288-116-1.png">
B.	<img src="/_files/images/mechanical-engineering/steam-boilers-and-engines/288-116-2.png">
C.	<img src="/_files/images/mechanical-engineering/steam-boilers-and-engines/288-116-3.png">
D.	<img src="/_files/images/mechanical-engineering/steam-boilers-and-engines/288-116-4.png">
Answer» D. <img src="/_files/images/mechanical-engineering/steam-boilers-and-engines/288-116-4.png">

Discussion

3336.	Which of the following compound steam engine requires a smaller flywheel ?
A.	Receiver type
B.	Tandem type
C.	Woolf type
D.	all of these
Answer» B. Tandem type

Discussion

3337.	A shaft of mass (mc)and stiffness (s) is fixed at one end and carries a mass (m) at the other end. The natural frequency of its transverse vibration is same as for longitudinal vibration.
A.	Yes
B.	No
Answer» C.

Discussion

3338.	The frictional torque transmitted by a disc or plate clutch is same as that of
A.	flat pivot bearing
B.	flat collar bearing
C.	conical pivot bearing
D.	truncated conical pivot bearing
Answer» C. conical pivot bearing

Discussion

3339.	The maximum gyroscopic couple acting on the ship tends to shear the holding down bolts.
A.	Correct
B.	Incorrect
Answer» B. Incorrect

Discussion

3340.	The lower pairs are __________ pairs.
A.	self-closed
B.	force-closed
Answer» B. force-closed

Discussion

3341.	For the isochronous Porter governor, the controlling force curve is a straight line passing through the origin.
A.	Correct
B.	Incorrect
Answer» B. Incorrect

Discussion

3342.	When no external force acts on a body, after giving it an initial displacement, the body is said to have free vibrations.
A.	True
B.	False
Answer» B. False

Discussion

3343.	A sliding pair has a completely constrained motion.
A.	Yes
B.	No
Answer» B. No

Discussion

3344.	In order to compare the capacity of boilers, the feed water temperature and working pressure are taken as
A.	50 C and normal atmospheric pressure
B.	50 C and 1.1 bar pressure
C.	100 C and normal atmospheric pressure
D.	100 C and 1.1 bar pressure
Answer» D. 100 C and 1.1 bar pressure

Discussion

3345.	Throttle governing of steam engines is a method of controlling the engine output by varying
A.	volume of intake steam
B.	pressure of intake steam
C.	temperature of intake steam
D.	all of these
Answer» C. temperature of intake steam

Discussion

3346.	For the same diameter and thickness of tube, a water tube boiler has __________ heating surface as compared to fire tube boiler.
A.	more
B.	less
C.	equal
Answer» B. less

Discussion

3347.	A condenser maintains a low pressure (below atmospheric) so as to obtain the maximum possible energy from steam and thus to secure a high efficiency.
A.	Agree
B.	Disagree
Answer» B. Disagree

Discussion

3348.	The amount of water evaporated from and at 100 C into dry and saturated steam is called evaporative capacity of a boiler.
A.	Yes
B.	No
Answer» C.

Discussion

3349.	The high pressure and low pressure cylinders in a Woolf type compound engine are regarded as having cranks
A.	180 to each other
B.	90 to each other
C.	0 to each other
D.	none of these
Answer» B. 90 to each other

Discussion

3350.	In a single acting steam engine
A.	the steam is admitted on one side of the piston and one working stroke is produced during each revolution of the crankshaft
B.	the steam is admitted, in turn, on both sides of the piston and one working stroke is produced during each revolution of the crankshaft
C.	the steam is admitted on one side of the piston and two working strokes are produced during each revolution of the crankshaft
D.	the steam is admitted, in turn, on both sides of the piston and two working strokes are produced during each revolution of the crankshaft.
Answer» B. the steam is admitted, in turn, on both sides of the piston and one working stroke is produced during each revolution of the crankshaft

Discussion

Explore topic-wise MCQs in Engineering.

The device attached to the steam chest for preventing explosions due to excessive internal pressure of steam is called

In a steam engine, superheated steam from the boiler is fed into the steam chest at a pressure of

The pressure of feed water has to be raised before its entry into the boiler. The pressure is raised by a device known as

Which of the following statement indicates the difference between Cornish boiler and Lancashire boiler ?

By compounding the expansion of steam in two or more cylinders, the ratio of expansion

The water tubes in a simple vertical boiler are

The ratio of heat actually used in producing the steam to the heat liberated in the furnace, is known as

A vessel into which the steam is exhausted and condensed after doing work in an engine cylinder or turbine is known as

The value of diagram factor depends upon

The function of an eccentric rod is

A receiver type compound engine, requires a lighter flywheel.

The function of a valve rod is

The principal function of a stop valve is to

The length of Cornish boiler varies from

The indicated thermal efficiency is defined as the

In surface condensers, the condensate and the cooling water mixes up.

A water level indicator is a device to indicate the exact water level in the boiler at any instant.

An economiser is generally placed between

In fire tube boilers

The efficiency of a boiler is defined as

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

A valve installed between the boiler and the feed pump is

A device used to empty the boiler whenever required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler, is called blow off cock.

The ratio of the energy required to produce the artificial draught (expressed in metres head or J/kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to natural draught, is known as

The actual power generated in the engine cylinder is called

The high steam and low water safety valve is not used in

The draught in locomotive boilers is produced by a

The ratio of heat actually used in producing the steam to the heat liberated in the furnace is known as equivalent evaporation from and at 100 C.

There is about 15 to 20% of coal saving when an economiser is used in a boiler.

Clearance ratio is the ratio of

In a boiler, the heat is lost

For a beam, as shown in the below figure, the deflection at C is (where E = Young's modulus for the beam material, and I = Moment of inertia of the beam section. )

The shear modulus of most materials with respect to the modulus of elasticity is

A watt's governor can work satisfactorily at speeds from

The boiler efficiency is given by (where m = Total mass of water evaporated into steam in kg/h, mf = Mass of fuel in kg/h, C = Calorific valve of fuel in kJ/kg of fuel, h = Total heat of steam in kJ/kg, and hf1 = Sensible heat of feed water in kJ /kg)

Which of the following compound steam engine requires a smaller flywheel ?

A shaft of mass (mc)and stiffness (s) is fixed at one end and carries a mass (m) at the other end. The natural frequency of its transverse vibration is same as for longitudinal vibration.

The frictional torque transmitted by a disc or plate clutch is same as that of

The maximum gyroscopic couple acting on the ship tends to shear the holding down bolts.

The lower pairs are __________ pairs.

For the isochronous Porter governor, the controlling force curve is a straight line passing through the origin.

When no external force acts on a body, after giving it an initial displacement, the body is said to have free vibrations.

A sliding pair has a completely constrained motion.

In order to compare the capacity of boilers, the feed water temperature and working pressure are taken as

Throttle governing of steam engines is a method of controlling the engine output by varying

For the same diameter and thickness of tube, a water tube boiler has __________ heating surface as compared to fire tube boiler.

A condenser maintains a low pressure (below atmospheric) so as to obtain the maximum possible energy from steam and thus to secure a high efficiency.

The amount of water evaporated from and at 100 C into dry and saturated steam is called evaporative capacity of a boiler.

The high pressure and low pressure cylinders in a Woolf type compound engine are regarded as having cranks

In a single acting steam engine