4791 + Mcqs in Mechanical Engineering Page 41 McqOptions

2001.	Shock resistance of steel is increased by adding
A.	nickel
B.	chromium
C.	nickel and chromium
D.	sulphur, lead and phosphorus
Answer» D. sulphur, lead and phosphorus

Discussion

2002.	Which of the following iron exist between 910 C and 1403 C?
A.	-iron
B.	-iron
C.	-iron
D.	-iron
Answer» D. -iron

Discussion

2003.	The process in which carbon and nitrogen both are absorbed by the metal surface to get it hardened is known as
A.	carburising
B.	cyaniding
C.	flame hardening
D.	induction hardening
Answer» C. flame hardening

Discussion

2004.	Steel containing upto 0.15% carbon, is known as
A.	mild steel
B.	dead mild steel
C.	medium carbon steel
D.	high carbon steel
Answer» C. medium carbon steel

Discussion

2005.	The casting ability of aluminium increases when __________ is added to aluminium.
A.	copper
B.	magnesium
C.	silicon
D.	lead and bismuth
Answer» D. lead and bismuth

Discussion

2006.	In a face centred cubic space lattice, there are
A.	nine atoms out of which eight atoms are located at the corners of the cube and one atom at its centre
B.	fourteen atoms out of which eight atoms are located at the corners of the cube and six atoms at the centres of six faces
C.	seventeen atoms out of which twelve atoms are located at the twelve corners of the hexagonal prism, one atom at the centre of each of the two hexagonal faces and three atoms are symmetrically arranged in the body of the cell
D.	none of the above
Answer» C. seventeen atoms out of which twelve atoms are located at the twelve corners of the hexagonal prism, one atom at the centre of each of the two hexagonal faces and three atoms are symmetrically arranged in the body of the cell

Discussion

2007.	The fuel used in a blast furnace is
A.	coal
B.	coke
C.	wood
D.	producer gas
Answer» C. wood

Discussion

2008.	Which of the following inpurity in cast iron makes it hard and brittle?
A.	Silicon
B.	Sulphur
C.	Manganese
D.	Phosphorus
Answer» C. Manganese

Discussion

2009.	Manganese bronze contains more copper than silicon bronze.
A.	Yes
B.	No
Answer» C.

Discussion

2010.	Conduction is the process of heat transfer from one particle of the body to another by the actual motion of the heated particles.
A.	True
B.	False
Answer» C.

Discussion

2011.	Moisture should be removed from refrigerants to avoid
A.	freezing at the expansion valve
B.	restriction to refrigerant flow
C.	corrosion of steel plates
D.	all of these
Answer» E.

Discussion

2012.	The use of heat exchangers is made in
A.	radiators in automobile
B.	condensers and boilers in steam plants
C.	condensers and evaporators in refrigeration and air conditioning units
D.	all of the above
Answer» E.

Discussion

2013.	The sensible heat gain is due to the __________ difference between the fresh air and the air in space.
A.	temperature
B.	humidity
Answer» B. humidity

Discussion

2014.	During cooling and dehumidification, dry bulb temperature
A.	remains constant
B.	increases
C.	decreases
Answer» D.

Discussion

2015.	Fourier's law of heat conduction gives the heat flow for
A.	irregular surfaces
B.	non-uniform temperature surfaces
C.	one dimensional cases only
D.	two dimensional cases only
Answer» D. two dimensional cases only

Discussion

2016.	An ordinary passenger aircraft requires a cooling system of capacity.
A.	2 TR
B.	4 TR
C.	8 TR
D.	10 TR
Answer» D. 10 TR

Discussion

2017.	The wet bulb temperature at 100% relative humidity is __________ dew point temperature.
A.	same as
B.	lower than
C.	higher than
Answer» B. lower than

Discussion

2018.	During humidification process, dry bulb temperature
A.	remains constant
B.	increases
C.	decreases
Answer» B. increases

Discussion

2019.	In air-conditioning of aeroplanes, using air as a refrigerant, the cycle used is
A.	reversed Carnot cycle
B.	reversed Joule cycle
C.	reversed Brayton cycle
D.	reversed Otto cycle
Answer» D. reversed Otto cycle

Discussion

2020.	The thermostatic expansion valve operates on the changes in the
A.	degree of superheat at exit from the evaporator
B.	temperature of the evaporator
C.	pressure in the evaporator
D.	none of the above
Answer» B. temperature of the evaporator

Discussion

2021.	Sulphur dioxide is extremely toxic and non-flammable.
A.	True
B.	False
Answer» B. False

Discussion

2022.	The transfer of heat from one body to another takes place only when there is a temperature difference between the bodies.
A.	Yes
B.	No
Answer» B. No

Discussion

2023.	In a vapour compression system, the condition of refrigerant before entering the expansion or throttle valve is
A.	high pressure saturated liquid
B.	wet vapour
C.	very wet vapour
D.	dry vapour
Answer» B. wet vapour

Discussion

2024.	The freezing point of R-12 is
A.	-86.6 C
B.	-95.2 C
C.	-107.7 C
D.	-135.8 C
Answer» E.

Discussion

2025.	The refrigerant supplied to a compressor must be
A.	superheated vapour refrigerant
B.	dry saturated liquid refrigerant
C.	a mixture of liquid and vapour refrigerant
D.	none of these
Answer» B. dry saturated liquid refrigerant

Discussion

2026.	The natural convection air cooled condensers are used in
A.	domestic refrigerators
B.	water coolers
C.	room air conditioners
D.	all of these
Answer» B. water coolers

Discussion

2027.	The process, generally used in winter air-conditioning to warm and humidity the air, is called
A.	humidification.
B.	dehumidification
C.	heating and humidification
D.	cooling and dehumidification
Answer» D. cooling and dehumidification

Discussion

2028.	Fouling factor is used
A.	in heat exchanger design as a safety factor
B.	in case of Newtonian fluids
C.	when a liquid exchanges heat with a gas
D.	none of the above
Answer» B. in case of Newtonian fluids

Discussion

2029.	In a shell and coil condenser, water flows in the shell and the refrigerant in the coil.
A.	True
B.	False
Answer» C.

Discussion

2030.	In a saturated air-water vapour mixture, the
A.	dry bulb temperature is higher than wet bulb temperature
B.	dew point temperature is lower than wet bulb temperature
C.	dry bulb, wet bulb and dew point temperature are same
D.	dry bulb temperature is higher than dew point temperature
Answer» D. dry bulb temperature is higher than dew point temperature

Discussion

2031.	Reynolds number is the ratio of
A.	energy transferred by convection to that by conduction
B.	kinematic viscosity to thermal diffusivity
C.	inertia force to viscous force
D.	none of the above
Answer» D. none of the above

Discussion

2032.	The wet bulb depression is zero when relative humidity is
A.	zero
B.	0.5
C.	0.75
D.	1.0
Answer» E.

Discussion

2033.	The conditioned air supplied to the room must have the capacity to take up
A.	room sensible heat load only
B.	room latent heat load only
C.	both room sensible heat and latent heat loads
D.	none of the above
Answer» D. none of the above

Discussion

2034.	The process of removing moisture from the air, without change in its dry bulb temperature, is called dehumidification.
A.	Correct
B.	Incorrect
Answer» B. Incorrect

Discussion

2035.	During sensible heating of air, specific humidity remains constant.
A.	Agree
B.	Disagree
Answer» B. Disagree

Discussion

2036.	Air refrigeration cycle is used in
A.	commercial refrigerators
B.	domestic refrigerators
C.	air-conditioning
D.	gas liquefaction
Answer» E.

Discussion

2037.	The specific humidity during dehumidification process
A.	remains constant
B.	increases
C.	decreases
Answer» D.

Discussion

2038.	The coefficient of performance of electrolux refrigerator is the ratio of
A.	heat supplied by the gas burner to the heat absorbed by the evaporator
B.	heat absorbed by the evaporator to the heat supplied by the gas burner
C.	heat supplied by the gas burner minus the heat absorbed by the evaporator to the heat supplied by the gas burner
D.	heat absorbed by the evaporator minus the heat supplied by the gas burner to the heat absorbed by the evaporator
Answer» C. heat supplied by the gas burner minus the heat absorbed by the evaporator to the heat supplied by the gas burner

Discussion

2039.	For a white body, absorptivity ( ) = 0, reflectivity ( ) = 1 and transmittivity ( ) = 0.
A.	Correct
B.	Incorrect
Answer» B. Incorrect

Discussion

2040.	Which of the following refrigerant has the lowest freezing point?
A.	R-11
B.	R-12
C.	R-22
D.	Ammonia
Answer» D. Ammonia

Discussion

2041.	The sulphur sticks, in case of leakage of ammonia refrigerant, gives white smoke.
A.	True
B.	False
Answer» B. False

Discussion

2042.	During gas charging in an ammonia vapour compression system, the connection is made at the compressor outlet.
A.	Agree
B.	Disagree
Answer» B. Disagree

Discussion

2043.	The aluminium alloy, mainly used, for anodized utensil manufacture, is
A.	duralumin
B.	Y-alloy
C.	magnalium
D.	hindalium
Answer» E.

Discussion

2044.	The toughness of a material __________ when it is heated.
A.	remains same
B.	decreases
C.	increases
Answer» C. increases

Discussion

2045.	An aluminium alloy with 11% silicon is used for making engine pistons by die casting technique.
A.	Yes
B.	No
Answer» B. No

Discussion

2046.	The austenite is a solid solution of carbon or iron carbide in gamma-iron.
A.	Correct
B.	Incorrect
Answer» B. Incorrect

Discussion

2047.	The coordination number of a face centred cubic space lattice is
A.	six
B.	twelve
C.	eighteen
D.	twenty
Answer» C. eighteen

Discussion

2048.	Spheroidal grey cast iron has graphite flakes.
A.	True
B.	False
Answer» B. False

Discussion

2049.	The brown smoke during the operation of a bessemer Converter indicates that the
A.	air is burning out silicon and managanese
B.	silicon and manganese has burnt and carbon has started oxidising
C.	the converter must be titled to remove the contents of the converter
D.	the brown smoke does not occur during the operation of a bessemer converter
Answer» B. silicon and manganese has burnt and carbon has started oxidising

Discussion

2050.	Monel metal is an alloy of
A.	nickel and copper
B.	nickel and chromium
C.	nickel, chromium and iron
D.	copper and chromium
Answer» B. nickel and chromium

Discussion

Explore topic-wise MCQs in Engineering.

Shock resistance of steel is increased by adding

Which of the following iron exist between 910 C and 1403 C?

The process in which carbon and nitrogen both are absorbed by the metal surface to get it hardened is known as

Steel containing upto 0.15% carbon, is known as

The casting ability of aluminium increases when __________ is added to aluminium.

In a face centred cubic space lattice, there are

The fuel used in a blast furnace is

Which of the following inpurity in cast iron makes it hard and brittle?

Manganese bronze contains more copper than silicon bronze.

Conduction is the process of heat transfer from one particle of the body to another by the actual motion of the heated particles.

Moisture should be removed from refrigerants to avoid

The use of heat exchangers is made in

The sensible heat gain is due to the __________ difference between the fresh air and the air in space.

During cooling and dehumidification, dry bulb temperature

Fourier's law of heat conduction gives the heat flow for

An ordinary passenger aircraft requires a cooling system of capacity.

The wet bulb temperature at 100% relative humidity is __________ dew point temperature.

During humidification process, dry bulb temperature

In air-conditioning of aeroplanes, using air as a refrigerant, the cycle used is

The thermostatic expansion valve operates on the changes in the

Sulphur dioxide is extremely toxic and non-flammable.

The transfer of heat from one body to another takes place only when there is a temperature difference between the bodies.

In a vapour compression system, the condition of refrigerant before entering the expansion or throttle valve is

The freezing point of R-12 is

The refrigerant supplied to a compressor must be

The natural convection air cooled condensers are used in

The process, generally used in winter air-conditioning to warm and humidity the air, is called

Fouling factor is used

In a shell and coil condenser, water flows in the shell and the refrigerant in the coil.

In a saturated air-water vapour mixture, the

Reynolds number is the ratio of

The wet bulb depression is zero when relative humidity is

The conditioned air supplied to the room must have the capacity to take up

The process of removing moisture from the air, without change in its dry bulb temperature, is called dehumidification.

During sensible heating of air, specific humidity remains constant.

Air refrigeration cycle is used in

The specific humidity during dehumidification process

The coefficient of performance of electrolux refrigerator is the ratio of

For a white body, absorptivity ( ) = 0, reflectivity ( ) = 1 and transmittivity ( ) = 0.

Which of the following refrigerant has the lowest freezing point?

The sulphur sticks, in case of leakage of ammonia refrigerant, gives white smoke.

During gas charging in an ammonia vapour compression system, the connection is made at the compressor outlet.

The aluminium alloy, mainly used, for anodized utensil manufacture, is

The toughness of a material __________ when it is heated.

An aluminium alloy with 11% silicon is used for making engine pistons by die casting technique.

The austenite is a solid solution of carbon or iron carbide in gamma-iron.

The coordination number of a face centred cubic space lattice is

Spheroidal grey cast iron has graphite flakes.

The brown smoke during the operation of a bessemer Converter indicates that the

Monel metal is an alloy of