MECHANICAL ENGINEERING INTERVIEW QUESTIONS

MECHANICAL ENGINEERING INTERVIEW QUESTIONS

1.)What are the Advantages and Disadvantages of using LPG in Car?
Ans. Advantages:-

a.) Complete combustion
b.) Fuel saving
c.) Homogenous combustion


Disadvantages:-

a.) As complete combustion is occurring ,more heat liberated,not advised for long journey, engine will be over heated
b.)Installation is difficult
c.)Reduce engine life efficiency


2.)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.

3.)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.