MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.) What do you understand by acoustic velocity ?

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

2.)Explain difference between cohesion, adhesion and capillarity ?

Ans: Cohesion is the attraction of like molecules.
Adhesion is the attraction of unlike molecules for each other.
Capillarity is the elevation or depression of a liquid surface in contact with a solid.

3.)What is bulk modulus of elasticity ?

Ans: It represents the compressibility of a fluid. It is the ratio of the change in unit pressure to the corresponding volume change per unit of volume.

4.)What is is entropic exponent ?
Ans: It is the ratio of the specific heat of a gas at constant pressure to the specific heat at constant volume.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.What is critical temperature in metals ?

Ans: It is the temperature at which the phase change occurs in metals.

2.What is coaxing ?

Ans: It is the process of improving fatigue properties by first under-stressing and then increasing the stress in small increments.

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

Factors Affecting Detonation In IC Engine

Factors Affecting Detonation In Internal Combustion Engine:

In an internal combustion engine cylinder sometime sudden and violent knocks are experienced, this is known as "Detonation". This knock is set up by a high pressure wave giving loud pulsating noise as it strikes against cylinder walls, cylinder head and piston.

Following are the main factors, which affects detonation:-

01) The fuel used in internal combustion engine will considerably effects on the chances of detonation. Alcohol and benzol do not cause detonation but it can not be use due its low calorific value and other objections to use as fuel. Again alcohol cannot blend with petrol in the presence of water.

02) The detonation is also promoted by increase in compression ratio. The compression ratio at which detonation just occurs is known as the Highest Useful Compression Ratio. Higher the compression ratio higher the chances of detonation and lower the output.

03) If the carbon deposits are in the cylinder and used excessive sparking temperature, the detonation will increased rapidly.

MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS

1.) What is the direction of tangential acceleration ?

Ans:The direction of tangential acceleration may be same or opposite to that of angular velocity.

2.)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.

3.)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.

4.)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.

Thermodynamic Processes