MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.)What is the difference between alpha iron, delta iron and gamma iron ?

Ans: The bcc form of iron exists between room temperature and 910°C, and between 1400°C and the melting point at 1539°C. The lower temperature form is known as "alpha"-iron and the higher temperature form as "delta"-iron. The face-centered cubic form existing between 910°C and 1400°C is referred to as "gamma-iron".

2.)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.

3.)What do you understand by eutectic ?

Ans: It is mechanical mixture of two or more phases which solidify simultaneously from the liquid alloy.

4.)Under what condition a convergent divergent nozzle required ?

Ans: When pressure ratio is greater than critical pressure ratio

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.)What is the difference between isotropic material and homogeneous material ?

Ans: In homogeneous material the composition is same throughout and in isotropic material the elastic constants are same in all directions.

2.)What do you understand by catenary cable ?

Ans: A cable attached to the supports and carrying its own weight.

3.)What is the difference between basic hole and basic shaft ?

Ans: A basic hole is one whose lower deviation is zero and in case of basic shaft the upper deviation is zero.

4.)In which process internal energy remains constant ?

Ans: Isothermal process.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.)Explain what you understand by the term hydrostatic paradox ?

Ans: Hydrostatic paradox is the phenomenon that the floor load of water in vessels of different shapes carrying water at same level depends only on the area of the bottom surface and not on the shape of the vessel.

2.)What do you understand by inversions and how many inversions are possible in a kinematic chain having 'n' links ?

Ans: Inversions are different mechanisms obtained by fixing different links in a kinematic chain but keeping relative motions of links unchanged with respect to one another. A kinematic chain

with 'n' links can have 'n' inversions.

3.)What is the difference between a machine and a mechanism ?

Ans: A mechanism consists of links forming a constrained kinematic chain. Its function is basically to transmit or modify motion. A machine is a mechanism but here we are concerned with forces to be transmitted and it is used to modify mechanical work.

4.)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.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.)Which Pump is more Efficient Centrifugal Pump or Reciprocating Pump?

Ans.Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to 

install. Lower initial cost and lower maintenance cost.

2.)Compare Brayton Cycle and Otto Cycle?

Ans.The heat addition and rejection processes in Otto cycle are of constant volume, whereas in Brayton cycle, they are of 

constant pressure.

-Otto cycle is the ideal cycle for spark ignition engines.

-Brayton cycle is the ideal cycle for gas power turbines.

3.)What is the purpose of Scrapper Ring?

Ans. Scrap the excess lube oil from the cylinder walls. there by preventing oil from entering combustion zone.

4.)State difference between AnitiFriction Bearing and Journal Bearing?

Ans. Generally, journal bearings have higher friction force, consume higher energy and release more heat, but they have larger contact surface, so normally used in low speed high load applications. In anti friction bearings friction is less. One object just rolls over each other.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.) What is the difference between Fan and Blower?

Ans.Fan is an air pushing device. Either Axial or Centrifugal type systems are used to move the air in low pressure. It is rotated 

by a motor separately.

When the fan is a housing of blades and motor, then it called as Blower. It directs the air in a single path with high pressure.

2.) What is Heat Rate of Power Plant?

Ans.Heat rate is a measure of the turbine efficiency. It is determined from the total energy input supplied to the Turbine divided by the electrical energy output.

3.) What is Hydrodynamic Cavitation?

Ans.Hydrodynamic cavitation describes the process of vaporization in a constrained channel at a specific velocity.

Bubble generation and Bubble implosion which occurs in a flowing liquid as a result of a decrease and subsequent increase in 

pressure.

4.)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.