Top 20 Interview Questions for Mechanical Engineer Jobs

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Top 20 Interview Questions for Mechanical Engineer Jobs

There was a time when people used to believe that only software engineering has its scope in the future, but as discussions over at show, mechanical engineering, popularly known as the mother of engineering, has become one of the most sought courses because of its massive job opportunities. Mechanical engineers know how to handle mechanical systems with their knowledge of design, manufacture, and operational processes. Every engineer has to face an interview to get hired, and to ace the interview, you need to be well prepared. To help you with that, here is a list of the top 20 interview questions for mechanical engineer jobs and their answers to help you prepare.

Differentiate between thermodynamics and heat transfer

Thermodynamics works on equilibrium states and changes one equilibrium state to another. Heat transfer, on the other hand, is a non-equilibrium process as it deals with systems that are not in thermal equilibrium. As per the gurus over at, this is a question you can expect to be asked.

Explain the role of nitrogen in welding

Nitrogen in welding is used to prevent porosity. It stops oxygen and air from entering the fused metal while welding. This is something you should be well-versed in as a mechanical engineer as discussed over at

Which gases can be used in place of nitrogen in welding?

During welding, Argon, Helium, or Carbon Dioxide can be used in place of Nitrogen to prevent porosity, which is another thing to know all about before your interview as per

Why are most of the gas containers cylindrical in shape?

Gas containers are made mostly cylindrical to withstand high pressure. Ideally, the sphere is the most efficient shape to withstand high internal gas pressure, but manufacturing that shape is quite costly, which is why a cylinder with a domed top and bottom is quite cheaper and has sufficient potential to withstand the internal gas pressure.

What is a periscope? Give its real-life application

A periscope is an optical instrument that is used for viewing objects which are above the level of sight. In real life, it is used in submarines to keep a check on enemies or any other danger.

What is the cause of white smoke in two-stroke locomotive engines?

White smoke is seen when the engine is running out of fuel. This condition is harmful to the engine as it may result in overheating and ultimately its failure. This is another question you can expect in your interview as explained over at

Can motor oil be used in a hydraulic system?

Motor oil can be used in a hydraulic system but we should avoid using it. This is because motor oil has lower sulfur content, has tackifiers, and other elements that are harmful to seals and other components of the hydraulic system. This is why we should use hydraulic fluids. Answering this question this way covers all the relevant areas as far as hydraulic systems go according to

Why do airplanes that are made up of thicker paper fly farther?

This is the case because the thicker the paper, the greater it’s mass and potential energy. Potential energy changes into kinetic energy while moving and this large kinetic energy provides a larger lift to the airplane, resulting in a large flight distance. You should prepare for this question according to the gurus over at

Explain the difference between the turbine and the pump

The turbine transfers the flow energy of the fluid to mechanical energy. On the contrary, the pump works to transfer mechanical energy to the fluid.

What is a Turboprop engine?

As its name suggests, a turboprop engine is a gas turbine engine that powers the propellers. It converts most of its thrust into rotational energy to power a propeller, making it highly reliable and efficient for aircraft designs.

What is the second law of thermodynamics?

The second law of thermodynamics depicts that the total entropy of an isolated system can never reduce over time. Having the laws of thermodynamics on your fingertips is important if you are to ace your interview as you are extremely likely to be asked about any one of them as per

Which pipes are used for steam lines?

Steel pipes with welded fitting are used for steam lines. As explained over at, this is the sort of knowledge that any mechanical engineering worth their salt should have.

Distinguish between a shear center and an elastic center.

The shear center is a center where the force can act with no twits while an elastic center is located at the center of gravity. According to the subject matter experts over at, this is another pretty common technical question in mechanical engineer job interviews.

What is meant by the greenfield project?

These are the projects which are built from scratch and do not create pollution. As people become more and more environmentally conscious, mechanical engineers are required to know all about these projects hence why it is a common interview question.

What is a cotter joint?

A cotter joint is one of the types of joint that are used to connect two rods that are under compressive or tensile stress. This joint is made up of steel or iron. A cotter joint is used for connecting a piston rod to the crosshead of the reciprocating steam engine.

What is the importance of tolerance in engineering?

You can’t design any product without tolerance as this increases the chances of rejection rate and overall product cost. You utilize tolerance in part dimension to reduce cost and facilitate the manufacturer. This is another concept that you need to brush up on before your interview as revealed in discussions over at

What is caustic embrittlement?

Caustic embrittlement is a physical change in metal. During the phenomenon, the boiler becomes brittle because of the accumulation of caustic soda. The gurus over at also recommend that you brush up on this phenomenon as well before your interview.

Explain the Otto cycle in brief

The Otto cycle describes the functioning of a typical spark-ignition four-stroke engine. Otto cycle is a description of what happens to gas as it is subjected to changes of volume, temperature, addition, or removal of heat. Knowledge of this cycle will help you ace your interview according to

What do you mean by annealing?

Annealing is the process of heating any material above the recrystallization temperature and cooling it after some time. This process increases the hardness and strength of metal material. The result of it is a reduction of dislocations in the crystal structure of the metal being annealed.

What is universal coupling?

Universal coupling is used to connect two shafts whose axes are inclined to each other, and it consists of a pair of hinges connected by a cross shaft.

These are some of the technical questions you can expect during your mechanical engineer job interview, with more questions to be found over at the highly-rated and

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