Sunday, October 24, 2021

Mechanical Engineering Top 25 Questions and Answers





Mechanical Engineering Top 25 Questions and Answers


01 ) Rotary swaging is a process for shaping


round bars and tubes.


02 ) Scab is a


sand casting defect.


03 ) The force of attraction between the individual particles bound together is known as


Adhesive


Explanation:


Adhesion → It is an attractive force between different kind of fluid molecules.

 

Cohesion → It is an attractive force between same kind of fluid molecules.


04 ) Superheating of the steam is done at


Constant pressure.


05 ) A football is rolling on ground, the motion of any point on its surface is


spherical.


06 ) Klein's diagram is used to find


Velocity and acceleration of various parts


Explanation:


Klein's diagram is used to find velocity and acceleration of various parts of single slider crank mechanism.


07 ) A pitot static tube is used to measure


Dynamic pressure.


Explanation:


A simple pitot tube measure stagnation pressure but a pitot static tube is used to measure dynamic pressure.


08 ) The constant pressure lines ……. on a Mollier diagram


Diverge from left to right.


Explanation:


Constant pressure lines diverge from left to right on Mollier diagram.

 

Mollier diagram is drawn between enthalpy (h) on y-axis and entropy (s) on x-axis.

 

The slope of constant pressure line on h-s curve is absolute temperature.



09 ) Extrusion is used for the manufacture of


seamless tubes


Explanation:


The pipes and tubes can be seamless or with seam. Tube with seam is manufactured by the various welding techniques. Seamless tubes are made by Extrusion and Piercing methods.


10 ) The advantage of the welding process is


Large number of metals and alloys, both similar and/or dissimilar can be joined.


11 ) Tool life is affected mainly with


Cutting speed.


Explanation:


Sequence of parameters affecting tool life is:

Cutting speed > feed > depth of cut.


12 ) Flank wear occurs on the


Relief face of the tool.


13 ) The gas turbine which is used in an aircraft is


Open cycle turbine


Explanation:


The gas turbine which is used in an aircraft is open cycle turbine.

 

In this cycle the gas is released from the turbine to the surroundings.


14 ) The type of compressor which is used in vapour compression refrigeration system for more than 100 tonnes capacity is


Centrifugal compressor.


Explanation:


The type of compressor which is used in vapour compression refrigeration system for more than 100 tonnes capacity is Centrifugal compressor and the type of compressor which is used in vapour compression refrigeration system for less than 100 tonnes capacity is reciprocating compressor.


15 ) The curved lines on Psychrometric chart indicate


Relative humidity.


16 ) The function of washer is to______________.


provide bearing area.


Explanation:


Function of the washer-

 

1. To distribute the concentrated load

 

2. To lock the nut and keep it at its place’

 

3. To provide load bearing area.


17 ) Pitot tube is used to measure………….


Velocity at a point.


18 ) Resilience means


Capacity of a material to absorb energy elastically.


Explanation:


Resilience - Capacity of a material to absorb energy elastically

 

Fatigue - Failure of material at loads less than at normal conditions

 

Stiffness - Resilience of the material to elastic deformation

 

Elasticity - Ability of the material to return to the original shape when load is removed.


19 ) Otto cycle consists of


Two constant volume & two isentropic processes


Explanation:


Carnot cycle consists of two isothermal and two isentropic processes.

 

Otto cycle consists of two constant volume and two isentropic processes.


20 ) What is an azeotrope?


A mixture of refrigerants without phase separation.



21 ) Piston compression rings are made of which one of the following?


Cast iron.


Explanation:


Since grey cast iron has properties of self-lubrication and damping of small vibrations they are widely used for machine base, engine frames, drainage pipes, elevator and industrial furnace counter weights, pump housings cylinder and piston rings of IC engines, flywheel etc.


22 ) Addition of Nickel to Steel helps in improving


Fatigue resistance.


23 ) Crystal structure of aluminium is


face-cantered cubic.


24 ) Heat is a


path function.



Explanation:


Energy is a point function

 

Entropy is related with Second law of thermodynamics

 

Gibb’s function is a point function.


25 ) Carnot cycle consists of


Two isothermal and two isentropic processes.



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Idioms mcq For Competitive Exams

Idioms mcq For Competitive Exams