MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS:-

1.). What is anisotropy ?

Ans: The phenomenon of different properties in different directions is called anisotropy.

2.)What is vapour pressure and when it becomes important ?

Ans: Vapour pressure is the partial pressure created by the vapour molecules when evaporation takes place within an enclosed space. It becomes important when negative
pressures are involved.

3.)Explain absolute viscosity ?

Ans: It is the ratio of shear stress and the gradient of velocity with distance between a fixed plate and moving plate (Its unit is Pa . s).

4.)What do you understand by acoustic velocity ?

Ans: Acoustic velocity is the speed of a small pressure (sound) wave in a fluid.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS:-

1.)How many governors are needed for safe turbine operation? Why?

Ans.-Two independent governors are needed for safe turbine operation. One is an over speed or emergency trip that shuts off the steam at 10 percent above running speed (maximum speed). The second, or main governor, usually controls speed at a constant rate; however, many applications have variable speed control.

2.)How is a fly ball governor used with a hydraulic control?

Ans.-As the turbine speeds up, the weights are moved outward by centrifugal force, causing linkage to open a pilot valve that admits and releases oil on either side of a piston or on one side of a spring-loaded piston. The movement of the piston controls the steam valves.

3.)What is meant by critical speed?

Ans.-It is the speed at which the machine vibrates most violently. It is due to many causes, such as imbalance or harmonic vibrations set up by the entire machine. To minimize damage, the turbine should be hurried through the known critical speed as rapidly as possible. (Caution, be sure the vibration is caused by critical speed and not by some other trouble).

Mechanical Engineering Interview Questions with answers

Mechanical Engineering Interview Questions with answers

1. What is the difference between Technology and Engineering? 

Ans. Engineering is application of
science. Technology shows various
methods of Engineering. A bridge can be
made by using beams to bear the load,by
an arc or by hanging in a cable; all
shows different technology but comes
under civil engineering and science
applied is laws of force/load
distribution.
 

2. How to Measure Temperature in Wet Bulb Thermometer?
 

Ans. Wet bulb temperature is measured
in a wet bulb thermometer by covering
the bulb with a wick and wetting it with
water. It corresponds to the dew point
temperature and relative humidity.
 

3. What are the Advantages and Disadvantages of using LPG in Car?
 

Ans. Advantages
1. Complete combustion
2. Fuel saving
3. Homogenous combustion
Disadvantages
1. As complete combustion is
occurring ,more heat liberated,not
advised for long journey, engine will be
over heated 2. Installation is difficult
3. Reduce engine life efficiency
 

4. What is the difference between Speed and Economic Speed?
 

Ans. The rated speed tells us about the
maximum speed which can be achieved by
a vehicle or some other machine but the
economical speed means the speed limit
at which the machine works efficiently
with least consumption of fuel.eg-in
normal bikes(not racing),the max.speed
limit shown on speedometer is upto 120
kmph but companies always advice their
customers to drive such bikes at around
60 kmph to have maximum mileage.
 

5. What is Powder Technology?
 

Ans. Powder technology is one of the
ways of making bearing material. In this
method metals like bronze, Al, Fe are
mixed and compressed to make an alloy.
 

6. State all the laws of Thermodynamics?
 

Ans. There are three laws of the
thermodynamics. First Law: Energy can
be neither created nor destroyed. It
can only change forms. In any process
in an isolated system, the total energy
remains the same. Second Law: When
two isolated systems in separate but
nearby regions of space, each in
thermodynamic equilibrium in itself, but
not in equilibrium with each other at
first, are at some time allowed to
interact, breaking the isolation that
separates the two systems, and they
exchange matter or energy, they will
eventually reach a mutual
thermodynamic equilibrium. The sum of
the entropies of the initial, isolated
systems is less than or equal to the
entropy of the final exchanging
systems. In the process of reaching a
new thermodynamic equilibrium, entropy
has increased, or at least has not
decreased. Third Law: As temperature
approaches absolute zero, the entropy of
a system approaches a minimum.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS:-

1.)What is Geyser Pressure Valve?

Ans. To release the pressure created inside due to evaporation of water.

2.)What is the function of scoop in BFP (Boiler Feed water pump) in Thermal Power Station?

Ans. The Function of Scoop tube is regulating the varying amount of oil level in the coupling during operation of infinite variable speed.

3.)Why is it that the maximum value which the residual stress can reach is the elastic limit of the material ?

Ans: A stress in excess of elastic limit, with no external force to oppose it, will relieve itself by plastic deformation until it reaches the value of the yield stress.

4.)Why fatigue strength decreases as size of a part increases beyond around 10 mm?

Ans: Perfection of material conditions is possible at lower sizes and as size increases, it is not possible to attain uniform structure of the material.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS:-

1.). What is boundary layer ?

Ans.-Boundary layer is the fluid layer in the neighborhood of a solid boundary where the effects of fluid friction are predominant.

2.)What is meant by precision ?

Ans.-Precision is defined as the ability of instrument to reproduce a certain set of readings within a given accuracy.

3.)What is the difference between path line and stream line ?

Ans.-A path line is a curve traced by a single fluid particle during its motion. A stream line is an imaginary line drawn in a flow field such that a tangent drawn at any point on this line represents the direction of the velocity vector. There is no flow across the stream line.

4.). What is the difference between steady and unsteady flow ?

Ans.-In steady flow the velocity at a given point does not change with time whereas in unsteady flow it changes with time.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS:-

1.)What is the difference between plane and spatial mechanism?

Ans: In plane mechanism all the links lie in the same plane whereas in spatial mechanism links lie in different planes.

2.)How many degrees of freedom are there in a constrained mechanism ?

Ans: One.

3.)What is the condition for correct gearing ?

Ans: According to condition of correct gearing, the common normal to the pitch surface should cut the line joining the centers at a fixed point.

4.)Differential between main function of flywheel and governor.

Ans: The function of flywheel is to reduce fluctuation of speed during a cycle and the function of governor is to control the mean speed over a period for output load variations. Flywheel has no influence on mean speed of prime mover and governor has no influence over cyclic speed fluctuation.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS:-

1.)What is the difference between anti-friction and hydrostatic bearings ?

Ans.-In anti-friction bearings rolling components are introduced between the sliding surfaces. In hydro static bearings lubricant is supplied at a high pressure to a pocket in the bearing.

2.)Define primary and secondary transducers ?

Ans.- A primary transducer senses a physical phenomena and converts it to an analogous output.The analogous output is then converted into an electrical signal by secondary transducer.

3.)What is the purpose of D-slide valve in steam engines ?

Ans.-It controls the piston position for cut off of steam, for release of steam and compression position for steam in cylinder.

4.)What is meant by loading ?

Ans.-During the act of measurement the measuring instrument takes energy from the signal source or measured medium and thus the signal source is altered. This effect is called loading.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS:-

1.)Explain the difference between poise and stoke.

Ans: Poise is the unit of viscosity in CGS unit and is measured in dyne sec/cm2.1 poise =10_1 Pa s.
Stoke is the unit of kinematic viscosity in CGS units and is measured in cm2/s.

2.)What do you understand by center of buoyancy ?

Ans: Center of buoyancy is the center of gravity of the displaced liquid and buoyant force acts through it.

3.)What is metacentre ?

Ans: Metacentre is the point at the intersection of the buoyancy with the vertical axis of the body.

4.)Under what condition a drill may not cut ?

Ans: When the cutting lips are not provided with clearance angles. It will cut if 12° clearance angle is ground.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.)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.

2.)Give example of rigid link and flexible link ?

Ans: Connecting rod and belt respectively.

3.). How many degrees of freedom are there in a constrained mechanism ?

Ans: One.

4.). What are Herringbone gears and what for these are used ?

Ans: Herringbone gears are double helical gears and used to eliminate axial thrust.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS:-

1.)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.

2.)What is Curie point ?

Ans: Curie point is the temperature at which ferromagnetic materials can no longer be magnetized by outside forces.

3.)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.

4.). What is the difference between column and strut ?

Ans: Both column and strut carry compressive load. Column is always vertical but strut as member of structure could carry axial compressive load in any direction.