MECHANICAL
ENGINEERING JOB INTERVIEW QUESTIONS:-
1.)
How shear forces are incurred in fluid flow?
Ans: Shear forces between fluid particles and boundary walls
and between the fluid particles themselves, result from the viscosity of the
real fluid.
2.) In straight polarity, to which terminal the electrode is connected?
Ans: Negative.
3.). Define flow work.
Ans: Flow work is the amount of mechanical energy required to push or force a flowing fluid across a section boundary.
4.). When a built up edge is formed while machining?
Ans: While machining ductile materials at high speed
2.) In straight polarity, to which terminal the electrode is connected?
Ans: Negative.
3.). Define flow work.
Ans: Flow work is the amount of mechanical energy required to push or force a flowing fluid across a section boundary.
4.). When a built up edge is formed while machining?
Ans: While machining ductile materials at high speed
5.). what is the effect of creep of belt in belt drive?
Ans: It decreases speed of driven pulley and the power output.
6.). what is the difference between kinetics and kinematics?
Ans: While kinematics studies the motion of a body without regard to the mass of body and forces acting on it, kinetics does not consider mass or forces.
7.) What is the difference between couple and angular momentum and how they are related ?
Ans: Couple is product of moment of inertia and angular acceleration. Angular momentum is the product of moment of inertia and angular speed. Time rate of change of angular
momentum of body is equal to external couple acting on the body.
8.). What is the difference between simple and compound machine?
Ans: In simple machine there is one point each for effort and load but in compound machine there are more than one point for application of load and effort.0\))
Ans: It decreases speed of driven pulley and the power output.
6.). what is the difference between kinetics and kinematics?
Ans: While kinematics studies the motion of a body without regard to the mass of body and forces acting on it, kinetics does not consider mass or forces.
7.) What is the difference between couple and angular momentum and how they are related ?
Ans: Couple is product of moment of inertia and angular acceleration. Angular momentum is the product of moment of inertia and angular speed. Time rate of change of angular
momentum of body is equal to external couple acting on the body.
8.). What is the difference between simple and compound machine?
Ans: In simple machine there is one point each for effort and load but in compound machine there are more than one point for application of load and effort.0\))
9.) What is the direction of tangential acceleration ?
Ans:The direction of tangential acceleration may be same or opposite to that of angular velocity.
10.)Why excess air is required to burn a fuel completely ?
Ans: Excess air is required to ensure adequate mixing of fuel and air, avoid smoke, minimize slagging in coal burning, and to ensure maximum steam output.
11.)Which type of plant will you recommend for remote location if power is required in six to twelve months time ?
Ans: Diesel engine power plant.
12.)What do you understand by forced convection ?
Ans: When convection heat transfer occurs between a solid body and a fluid and where circulation of fluid is caused and controlled by some mechanical.
13.). What is Sentinel Relief Valve?
Ans. It’s a special type valve system. The valve will open when exhaust casing pressure is excessive (high). The valve warns the operator only; it is not intended to relieve the casing pressure.
14.)What is boundary layer thickness in turbulent boundary layer ?
Ans: In ease of turbulent boundary layer, boundary layer thickness is defined as the distance from solid surface at which the fluid velocity is 99% of the undisturbed free stream velocity.
Near the surface of solid, there is laminar flow which changes to buffer zone and finally turbulent region.
15.). Stirling cycle with regenerative arrangement and Carnot cycle operate within same temperature limits. What can be said about thermal efficiencies of these two ?
Ans: Thermal n of both will be same.
16.). What is the frequency of secondary imbalance in four-stroke engine ?
Ans: Two times the engine speed.
17.)What is the difference between Specification,Codes, Standards?
Ans. Specification is describing properties of any type of materials. Code is procedure of acceptance and rejection criteria. Standard is accepted values and compare other with it.
18.) What is difference between Welding and Brazing?
Ans. In Welding concentrated heat (high temperature) is applied at the joint of metal and fuse together. In Brazing involves significantly lower temperatures and does not entail the melting of base metals. Instead, a filler metal is melted and forced to flow into the joint through capillary action.
19.)What is the purpose of Scrapper Ring?
Ans. It scraps the excess lube oil from the cylinder walls. there by preventing oil from entering combustion zone.
20)What is DTSI Technology?
Ans. DTSI stands for Digital Twin Spark Plug Ignition. The vehicles with DTSI Technology use 2 spark plugs which are controlled by digital circuit. It results in efficient combustion of air fuel mixture.
--»Digital - Since the spark generation will be initiated by a microchip.
--»Twin - Since two spark plugs will be used.
--»Spark ignition - Since the ignition will be done via a spark.
21.)What is the difference between Sudden Force and Impact Force?
Ans. An impact is a high force or shock applied over a short time period when two or more bodies collide.
A force which applies on the body (material) suddenly is known as sudden force.
22).What is ATFT Technology used in Honda Hunk?
Ans.-ATFT means Advance Tumble Flow Induction Technology,
Tumble flow means swirling. In this technology fuel air mixture from the carburetor into the engine cylinder with a swirl action. The advantage being one gets a more efficient burning of fuel hence more power and better fuel economy with lesser emissions.
23).Why we do not use same technology to start both SI /CI engine
Ans.-The S.I. or spark ignition engine uses petrol as a fuel and the C.I. or compression ignition engine uses diesel as a fuel. Both the fuels has different compression ratio.
In SI engine the compression ratio is 8-12:1.
In CI engine the compression ratio is 16-22:1.
So in case of SI engine, the compression ratio is not sufficient for fuel to burn so a spark plug is used, whereas in ci engine, the compression ratio is so high that due to its internal heat the fuel is combusted so there is no need for a spark plug. so the technology used in si engine is different from CI engine.
24).What is a Newtonian fluid?
Ans.-A Newtonian fluid possesses a linear stress strain relationship curve and it passes through the origin. The fluid properties of a Newtonian fluid do not change when any force acts upon it.
MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS :
1.)
Explain
the difference between the points of inflexion and contraflexure.
Ans: At points of inflexion in a loaded beam the bending moment is zero and at points of contraflexure in loaded beam the bending moment changes sign from increasing to decreasing.
2.)What is the difference between proof resilience and modulus of resilience ?
Ans: Proof resilience is the maximum strain energy that can be stored in a material without permanent deformation. Modulus of resilience is the maximum strain energy stored in a material per unit volume.
3.)What do you understand by critical points in iron, iron-carbide diagram ?
Ans: The temperatures at which the phase changes occur are called critical points (or temperatures).
4.) Define buckling factor.
Ans: It is the ratio of the equivalent length of column to the minimum radius of gyration.)))))))
Ans: At points of inflexion in a loaded beam the bending moment is zero and at points of contraflexure in loaded beam the bending moment changes sign from increasing to decreasing.
2.)What is the difference between proof resilience and modulus of resilience ?
Ans: Proof resilience is the maximum strain energy that can be stored in a material without permanent deformation. Modulus of resilience is the maximum strain energy stored in a material per unit volume.
3.)What do you understand by critical points in iron, iron-carbide diagram ?
Ans: The temperatures at which the phase changes occur are called critical points (or temperatures).
4.) Define buckling factor.
Ans: It is the ratio of the equivalent length of column to the minimum radius of gyration.)))))))
MECHANICAL ENGINEERING
JOB INTERVIEW QUESTIONS :
1.)What is the difference
between mechanical advantage and velocity ratio ?
Ans: Mechanical advantage is the ratio of load lifted and the effort applied. Velocity ratio is the ratio between the distance moved by the effort applied and the distance moved by the load lifted.
2.)Give example of rigid link and flexible link ?
Ans: Connecting rod and belt respectively.
3.)What is the damping ratio for non-oscillating system and under-damped system ?
Ans: More than unity and less than unity respectively.
4.)State D' Alembert's principle and write down its importance.
Ans: D' Alembert's principle enables us to replace a given system by a massless rigid body so that forces acting on it are equivalent to those on real body and then enables to determine the forces transmitted to other paired rigid body. This way the problem of kinetics gets reduced to equivalent problem on statics.))))
Ans: Mechanical advantage is the ratio of load lifted and the effort applied. Velocity ratio is the ratio between the distance moved by the effort applied and the distance moved by the load lifted.
2.)Give example of rigid link and flexible link ?
Ans: Connecting rod and belt respectively.
3.)What is the damping ratio for non-oscillating system and under-damped system ?
Ans: More than unity and less than unity respectively.
4.)State D' Alembert's principle and write down its importance.
Ans: D' Alembert's principle enables us to replace a given system by a massless rigid body so that forces acting on it are equivalent to those on real body and then enables to determine the forces transmitted to other paired rigid body. This way the problem of kinetics gets reduced to equivalent problem on statics.))))
MECHANICAL ENGINEERING
JOB INTERVIEW QUESTIONS :
1.)What are two essential
conditions of perfect gas ?
Ans: It satisfies equation of state and its specific heats are constant.
2.)Under what condition the work done in reciprocating compressor will be least ?
Ans: It is least when compression process approaches isothermal. For this purpose, attempts are made to cool the air during compression.
3.). What is pitting ? How it is caused ?
Ans: Non uniform corrosion over the entire metal surface, but occuring only in small pits is called pitting. It is caused by lack of uniformity in metal.
4.)What is caustic embrittlement ?
Ans: It is the actual physical change in metal that makes it extremely brittle and filled with minute cracks. It occurs particularly in the seams of rivetted joints and around the rivet holes.)))))
Ans: It satisfies equation of state and its specific heats are constant.
2.)Under what condition the work done in reciprocating compressor will be least ?
Ans: It is least when compression process approaches isothermal. For this purpose, attempts are made to cool the air during compression.
3.). What is pitting ? How it is caused ?
Ans: Non uniform corrosion over the entire metal surface, but occuring only in small pits is called pitting. It is caused by lack of uniformity in metal.
4.)What is caustic embrittlement ?
Ans: It is the actual physical change in metal that makes it extremely brittle and filled with minute cracks. It occurs particularly in the seams of rivetted joints and around the rivet holes.)))))
MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS :
1.)
What is view
factor ?
Ans: View factor is dependent upon geometry of the two surfaces exchanging radiation.
2.)Explain the effects of alloying chromium and nickel in stainless steel.
Ans: Addition of nickel and chromium increases the tensile strength and increase in resistance to corrosion takes place.
3.)Mention two types of dislocations.
Ans: Dislocation refers to a break in the continuity of the lattice. In edge dislocation, one plane of atoms gets squeezed out. In screw dislocation the lattice atoms move from their regular ideal positions.
4.) What are the principal constituents of brass?
Ans: Principal constituents of brass are copper and zinc.))))
Ans: View factor is dependent upon geometry of the two surfaces exchanging radiation.
2.)Explain the effects of alloying chromium and nickel in stainless steel.
Ans: Addition of nickel and chromium increases the tensile strength and increase in resistance to corrosion takes place.
3.)Mention two types of dislocations.
Ans: Dislocation refers to a break in the continuity of the lattice. In edge dislocation, one plane of atoms gets squeezed out. In screw dislocation the lattice atoms move from their regular ideal positions.
4.) What are the principal constituents of brass?
Ans: Principal constituents of brass are copper and zinc.))))
MECHANICAL ENGINEERING
JOB INTERVIEW QUESTIONS :
1.)Explain the difference
between rotational and irrotational flow.
Ans:In rotational flow the vorticity is non zero and in irrotational flow it is zero. In irrotational flow the net rotation of a fluid element about its own mass centre is zero as it moves from one place to another. For it, dv/dx = du/dy.
2.)What is boundary layer ?
Ans:Boundary layer is the fluid layer in the neighbourhood of a solid boundary where the effects of fluid friction are predominant.
3.). In which type of lubrication the starting friction is low ?
Ans:In hydrostatic lubrication.
4.)What is the necessary and sufficient condition for bodies in floatation to be in stable equilibrium ?
Ans:Centre of gravity of body should be located below metacentre.))))
Ans:In rotational flow the vorticity is non zero and in irrotational flow it is zero. In irrotational flow the net rotation of a fluid element about its own mass centre is zero as it moves from one place to another. For it, dv/dx = du/dy.
2.)What is boundary layer ?
Ans:Boundary layer is the fluid layer in the neighbourhood of a solid boundary where the effects of fluid friction are predominant.
3.). In which type of lubrication the starting friction is low ?
Ans:In hydrostatic lubrication.
4.)What is the necessary and sufficient condition for bodies in floatation to be in stable equilibrium ?
Ans:Centre of gravity of body should be located below metacentre.))))
1.)Define surface tension
?
Ans: Surface tension of a liquid is the work that must be done to bring enough molecules from inside the liquid to the surface to form one new unit area of that surface. (Its unit is Nm/m2 or N/m).
2.)What is the difference between perfect and real fluids ?
Ans: Perfect fluids are treated as if all tangential forces created by friction can be ignored. Real fluids refer to the cases in which friction must properly be taken into account.
3.)Which factors affect tool size ?
Ans: Following factors influence tool size :
1. Process variable (speed, feed and depth of cut)
2. Tool material
3. Tool geometry
4. Work piece material, its hardness, microstructure and surface condition
5. Cutting conditions.
4.)When the motion of fluid is fully known ?
Ans: The motion of a fluid is fully known when the velocity of each of its particles can be specified.
Ans: Surface tension of a liquid is the work that must be done to bring enough molecules from inside the liquid to the surface to form one new unit area of that surface. (Its unit is Nm/m2 or N/m).
2.)What is the difference between perfect and real fluids ?
Ans: Perfect fluids are treated as if all tangential forces created by friction can be ignored. Real fluids refer to the cases in which friction must properly be taken into account.
3.)Which factors affect tool size ?
Ans: Following factors influence tool size :
1. Process variable (speed, feed and depth of cut)
2. Tool material
3. Tool geometry
4. Work piece material, its hardness, microstructure and surface condition
5. Cutting conditions.
4.)When the motion of fluid is fully known ?
Ans: The motion of a fluid is fully known when the velocity of each of its particles can be specified.
1.)What happens if
gasoline is used in a Diesel engine?Diesel engine will work ?
Ans.:No, It will not work,as the Compression ratio of Petrol engine is 6 to 10 & that of Diesel engine is 15 to 22. Thus on such high compression, gasoline gets highly compressed & it may blast.
2.)Why different types of sound are produced in different bikes though they say run on SI engine?
Ans:Engine specifications are different in different manufactures like as Bore Diameter(CC), Ignition timing.Also the exhaust passage take more responsible for sound.
3.)1 hp how much watt?
Ans: 746.2Watt
4.)Explain Bicycle rear wheel Sprocket working?
Ans:Rear wheel sprocket works under the principle of ratchet and pawl.
Ans.:No, It will not work,as the Compression ratio of Petrol engine is 6 to 10 & that of Diesel engine is 15 to 22. Thus on such high compression, gasoline gets highly compressed & it may blast.
2.)Why different types of sound are produced in different bikes though they say run on SI engine?
Ans:Engine specifications are different in different manufactures like as Bore Diameter(CC), Ignition timing.Also the exhaust passage take more responsible for sound.
3.)1 hp how much watt?
Ans: 746.2Watt
4.)Explain Bicycle rear wheel Sprocket working?
Ans:Rear wheel sprocket works under the principle of ratchet and pawl.
1.)On what factors the
efficiency of pump depends ?
Ans: Efficiency of a pump (centrifugal) depends on the size, speed, and proportions of the impeller and casing.
2.)What is the function of a transducer element ?
Ans:The function of a transducer element is to sense and convert the desired input into a more convenient and practicable form to be handled by measurement system.
3.)What is Sentinel Relief Valve?
Ans. It’s a special type valve system. The valve will open when exhaust casing pressure is excessive (high). The valve warns the operator only; it is not intended to relieve the casing pressure.
4.)What is the difference between shaper and planner ?
Ans.->Shaper has one tool head wherear planner has more than one tool head.
>In shaper, workpiece is stationary and tool reciprocates with ram. Whereas in planner ,workpiece rotate and tool stationary.
>Shaper is used for light work whereas planner is used for heavy work.
Ans: Efficiency of a pump (centrifugal) depends on the size, speed, and proportions of the impeller and casing.
2.)What is the function of a transducer element ?
Ans:The function of a transducer element is to sense and convert the desired input into a more convenient and practicable form to be handled by measurement system.
3.)What is Sentinel Relief Valve?
Ans. It’s a special type valve system. The valve will open when exhaust casing pressure is excessive (high). The valve warns the operator only; it is not intended to relieve the casing pressure.
4.)What is the difference between shaper and planner ?
Ans.->Shaper has one tool head wherear planner has more than one tool head.
>In shaper, workpiece is stationary and tool reciprocates with ram. Whereas in planner ,workpiece rotate and tool stationary.
>Shaper is used for light work whereas planner is used for heavy work.
1.). What is meant by
quality of steam ?
Ans: It refers to amount of unevaporated moisture in steam. If steam is perfectly dry, it's quality is 100%.
2.)If superheat and condenser temperatures are unchanged and if pressure of steam is increased, then what happens to dryness fraction of steam after isentropic expansion ?
Ans: It will decrease.
3.)Water/steam injection in gas turbines increases power output. What is the limit and reasons for same ?
Ans: Water/steam injection is not allowed beyond 5% of compressor flow to avoid flame out in combustion and to minimise operating cost and impact on inspection intervals.
4.). How steam/water injection in combustion zone lowers NOx formation.
Ans: It lowers the flame and gas temperatures.
Ans: It refers to amount of unevaporated moisture in steam. If steam is perfectly dry, it's quality is 100%.
2.)If superheat and condenser temperatures are unchanged and if pressure of steam is increased, then what happens to dryness fraction of steam after isentropic expansion ?
Ans: It will decrease.
3.)Water/steam injection in gas turbines increases power output. What is the limit and reasons for same ?
Ans: Water/steam injection is not allowed beyond 5% of compressor flow to avoid flame out in combustion and to minimise operating cost and impact on inspection intervals.
4.). How steam/water injection in combustion zone lowers NOx formation.
Ans: It lowers the flame and gas temperatures.
1.). What is factor of
evaporation ?
Ans: It is the ratio of heat change from feed water to steam and the heat of vaporization of steam at atmospheric pressure.
2.)At what pressure and temperature the density of water and steam is same ?
Ans: At 225 kg/cm2 and 74.6° C.
3.)What is meant by quality of steam ?
Ans: It refers to amount of unevaporated moisture in steam. If steam is perfectly dry, it's quality is 100%.
4.)What do you understand by effectiveness of heat exchanger ?
Ans: Effectiveness of heat exchanger = actual heat transfer/maximum possible heat transfer.
Ans: It is the ratio of heat change from feed water to steam and the heat of vaporization of steam at atmospheric pressure.
2.)At what pressure and temperature the density of water and steam is same ?
Ans: At 225 kg/cm2 and 74.6° C.
3.)What is meant by quality of steam ?
Ans: It refers to amount of unevaporated moisture in steam. If steam is perfectly dry, it's quality is 100%.
4.)What do you understand by effectiveness of heat exchanger ?
Ans: Effectiveness of heat exchanger = actual heat transfer/maximum possible heat transfer.
1)What is Sentinel Relief
Valve?
Ans. It’s a special type valve system. The valve will open when exhaust casing pressure is excessive (high). The valve warns the operator only; it is not intended to relieve the casing pressure.
2)What is the difference between Specification,Codes, Standards?
Ans. Specification is describing properties of any type of materials. Code is procedure of acceptance and rejection criteria.
Standard is accepted values and compare
other with it.
3.) What is difference between Welding and Brazing?
Ans. In Welding concentrated heat (high temperature) is applied at the joint of metal and fuse together. In Brazing involves significantly lower temperatures and does not entail the melting of base metals. Instead, a filler metal is melted and forced to flow into the joint through capillary action.
Ans. It’s a special type valve system. The valve will open when exhaust casing pressure is excessive (high). The valve warns the operator only; it is not intended to relieve the casing pressure.
2)What is the difference between Specification,Codes, Standards?
Ans. Specification is describing properties of any type of materials. Code is procedure of acceptance and rejection criteria.
Standard is accepted values and compare
other with it.
3.) What is difference between Welding and Brazing?
Ans. In Welding concentrated heat (high temperature) is applied at the joint of metal and fuse together. In Brazing involves significantly lower temperatures and does not entail the melting of base metals. Instead, a filler metal is melted and forced to flow into the joint through capillary action.
1.
What is
Difference between Hardness and Toughness?
Ans. Toughness is the ability of a material to absorb energy.
Hardness is the ability of a material to withstand wear.
2.What does F.O.F Stand for Piping Design?
Ans.Face of Flange, The F.O.F (Raised face and Flat face) is used to know the accurate dimension of the flange in order to avoid the minute errors in measurement in case of vertical or horizontal pipe lines.
3.Difference between Performance and Efficiency?
Ans.The accomplishment of a given task measured against preset known standards of accuracy, completeness, cost, and speed is called as Performance.
Efficiency is defined as the input given and the work obtained from that input like money, time, labour etc. It’s the main factor of productivity.
Ans. Toughness is the ability of a material to absorb energy.
Hardness is the ability of a material to withstand wear.
2.What does F.O.F Stand for Piping Design?
Ans.Face of Flange, The F.O.F (Raised face and Flat face) is used to know the accurate dimension of the flange in order to avoid the minute errors in measurement in case of vertical or horizontal pipe lines.
3.Difference between Performance and Efficiency?
Ans.The accomplishment of a given task measured against preset known standards of accuracy, completeness, cost, and speed is called as Performance.
Efficiency is defined as the input given and the work obtained from that input like money, time, labour etc. It’s the main factor of productivity.
1. What is the difference
between scavenging and supercharging ?
Ans: Scavenging is process of flushing out burnt gases from engine cylinder by introducing fresh air in the cylinder before exhaust stroke ends. Supercharging is the process of supplying higher mass of air by compressing the atmospheric air.
2.What is pitting ? How it is caused ?
Ans: Non uniform corrosion over the entire metal surface, but occuring only in small pits is called pitting. It is caused by lack of uniformity in metal.
3.Why large boilers are water tube type ?
Ans: Water tube boilers raise steam fast because of large heat transfer area and positive water circulation. Thus they respond faster to fluctuations in demand. Further single tube failure does not lead to catastrophy.
Ans: Scavenging is process of flushing out burnt gases from engine cylinder by introducing fresh air in the cylinder before exhaust stroke ends. Supercharging is the process of supplying higher mass of air by compressing the atmospheric air.
2.What is pitting ? How it is caused ?
Ans: Non uniform corrosion over the entire metal surface, but occuring only in small pits is called pitting. It is caused by lack of uniformity in metal.
3.Why large boilers are water tube type ?
Ans: Water tube boilers raise steam fast because of large heat transfer area and positive water circulation. Thus they respond faster to fluctuations in demand. Further single tube failure does not lead to catastrophy.
1.) What is the
difference between isotropic and anisotropic materials ?
Ans: If a material exhibits same mechanical properties regardless of loading direction, it is
isotropic, e.g., homogeneous cast materials. Materials lacking this property are anisotropic.
2.) What are orthotropic materials ?
Ans: It is a special class of anisotropic materials which can be described by giving their
prop¬erties in three perpendicular directions e.g. wood; composites.
3.) What is view factor ?
Ans: View factor is dependent upon geometry of the two surfaces exchanging radiation.
4.) Mention two types of dislocations.
Ans: Dislocation refers to a break in the continuity of the lattice. In edge dislocation , one plane
of atoms gets squeezed out. In screw dislocation the lattice atoms move fom their regular ideal
positions.
Ans: If a material exhibits same mechanical properties regardless of loading direction, it is
isotropic, e.g., homogeneous cast materials. Materials lacking this property are anisotropic.
2.) What are orthotropic materials ?
Ans: It is a special class of anisotropic materials which can be described by giving their
prop¬erties in three perpendicular directions e.g. wood; composites.
3.) What is view factor ?
Ans: View factor is dependent upon geometry of the two surfaces exchanging radiation.
4.) Mention two types of dislocations.
Ans: Dislocation refers to a break in the continuity of the lattice. In edge dislocation , one plane
of atoms gets squeezed out. In screw dislocation the lattice atoms move fom their regular ideal
positions.
1.)What is endurance
limit and what is its value for steel ?
Ans: Endurance limit is the maximum level of fluctuating stress which can be tolerated
indefinitely. In most steels this stress is approximately 50% of the ultimate tensile strength and
it is defined as the stress which can be endured for ten million reversals of stress.
2.)What do you understand by sulphur print ?
Ans: Sulphides, when attached with dilute acid, evolve hydrogen sulphide gas which stains
bromide paper and therefore can be readily detected in ordinary steels and cast irons . While
sulphur is not always as harmful as is sometimes supposed, a sulphur print is a ready guide to
the distribution of segregated impurities in general.
3.) What is the different between brass and bronze ?
Ans: Brass is an alloy of copper with zinc; and bronze is alloy of copper with tin.
4.) What is the effect of addition of zinc in copper? What is the use of 70/30 brass ?
Ans: By addition of zinc in copper, both tensile strength and elongation increases. The 70/30
brass has excellent deep drawing property and is used for making radiator fins.
Ans: Endurance limit is the maximum level of fluctuating stress which can be tolerated
indefinitely. In most steels this stress is approximately 50% of the ultimate tensile strength and
it is defined as the stress which can be endured for ten million reversals of stress.
2.)What do you understand by sulphur print ?
Ans: Sulphides, when attached with dilute acid, evolve hydrogen sulphide gas which stains
bromide paper and therefore can be readily detected in ordinary steels and cast irons . While
sulphur is not always as harmful as is sometimes supposed, a sulphur print is a ready guide to
the distribution of segregated impurities in general.
3.) What is the different between brass and bronze ?
Ans: Brass is an alloy of copper with zinc; and bronze is alloy of copper with tin.
4.) What is the effect of addition of zinc in copper? What is the use of 70/30 brass ?
Ans: By addition of zinc in copper, both tensile strength and elongation increases. The 70/30
brass has excellent deep drawing property and is used for making radiator fins.
1.)What is the difference
between higher pair and lower pair ?
Ans: Higher pair has point or line contact between two links and lower pair has surface contact between two links while in motion.
2.). For what purpose the bifiler suspension system used ?
Ans: It is used to determine moment of inertia.
3.)How helical gears are capable of transmitting heavy load at high speed compared to spur gears ?
Ans: Helical gears have smooth engagement and two pairs of teeth are always in contact.
4.). What is the effect of inertia of reciprocating parts on the engine frame ?
Ans: Inertia of reciprocating parts subjects engine frame to the force required to accelerate the reciprocating mass and thus subject them to primary disturbing force and secondary disturbing force. Secondary disturbing force comes into play due to obliquity of connecting rod and has twice the frequency of the primary force.
Ans: Higher pair has point or line contact between two links and lower pair has surface contact between two links while in motion.
2.). For what purpose the bifiler suspension system used ?
Ans: It is used to determine moment of inertia.
3.)How helical gears are capable of transmitting heavy load at high speed compared to spur gears ?
Ans: Helical gears have smooth engagement and two pairs of teeth are always in contact.
4.). What is the effect of inertia of reciprocating parts on the engine frame ?
Ans: Inertia of reciprocating parts subjects engine frame to the force required to accelerate the reciprocating mass and thus subject them to primary disturbing force and secondary disturbing force. Secondary disturbing force comes into play due to obliquity of connecting rod and has twice the frequency of the primary force.
MECHANICAL ENGINEERING
JOB INTERVIEW QUESTIONS:-
1.)What for water/steam is injected in combustion zones of a gas turbine ?
Ans: Water/steam is injected to limit the amount of NOx formed by lowering the flame and gas temperatures.
2.)What is the name given to combined process of cooling and humidifying ?
Ans: Evaporative Cooling.
3.)When it can be said that a fluid is Newtonian ?
Ans: When the shear stress is directly proportional to velocity gradient.
4.)Out of 2 stroke SI engine, 4 stroke SI engine, and 4 stroke CI engine, how the brake thermal efficiency behaves if these are to be used for road vehicles ?
Ans: 4 stroke CI engine has highest brake thermal efficiency followed by 4 stroke SI engine and the 2 stroke SI has lowest brake thermal efficiency.
1.)What for water/steam is injected in combustion zones of a gas turbine ?
Ans: Water/steam is injected to limit the amount of NOx formed by lowering the flame and gas temperatures.
2.)What is the name given to combined process of cooling and humidifying ?
Ans: Evaporative Cooling.
3.)When it can be said that a fluid is Newtonian ?
Ans: When the shear stress is directly proportional to velocity gradient.
4.)Out of 2 stroke SI engine, 4 stroke SI engine, and 4 stroke CI engine, how the brake thermal efficiency behaves if these are to be used for road vehicles ?
Ans: 4 stroke CI engine has highest brake thermal efficiency followed by 4 stroke SI engine and the 2 stroke SI has lowest brake thermal efficiency.
MECHANICAL ENGINEERING
JOB INTERVIEW QUESTIONS:-
1.)Explain the difference between rotational and irrotational flow.
Ans:In rotational flow the vorticity is non zero and in irrotational flow it is zero. In irrotational flow the net rotation of a fluid element about its own mass centre is zero as it moves from one place to another. For it, dv/dx = du/dy.
2.)What is boundary layer ?
Ans:Boundary layer is the fluid layer in the neighbourhood of a solid boundary where the effects of fluid friction are predominant.
3.). In which type of lubrication the starting friction is low ?
Ans:In hydrostatic lubrication.
4.)What is the necessary and sufficient condition for bodies in floatation to be in stable equilibrium ?
Ans:Centre of gravity of body should be located below metacentre.
1.)Explain the difference between rotational and irrotational flow.
Ans:In rotational flow the vorticity is non zero and in irrotational flow it is zero. In irrotational flow the net rotation of a fluid element about its own mass centre is zero as it moves from one place to another. For it, dv/dx = du/dy.
2.)What is boundary layer ?
Ans:Boundary layer is the fluid layer in the neighbourhood of a solid boundary where the effects of fluid friction are predominant.
3.). In which type of lubrication the starting friction is low ?
Ans:In hydrostatic lubrication.
4.)What is the necessary and sufficient condition for bodies in floatation to be in stable equilibrium ?
Ans:Centre of gravity of body should be located below metacentre.
1.) What are the
principal constituents of brass?
Ans: Principal constituents of brass are copper and zinc.
2.) What is Curie point ?
Ans: Curie point is the temperature at which ferromagnetic materials can no longer be
magnetised by outside forces.
3). Which element is added in steel to increase resistance to corrosion ?
Ans: Chromium.
4.) Whether individual components in composite materials retain their characteristics or not?
Ans: yes.
Ans: Principal constituents of brass are copper and zinc.
2.) What is Curie point ?
Ans: Curie point is the temperature at which ferromagnetic materials can no longer be
magnetised by outside forces.
3). Which element is added in steel to increase resistance to corrosion ?
Ans: Chromium.
4.) Whether individual components in composite materials retain their characteristics or not?
Ans: yes.
No comments:
Post a Comment