Mechanical Engineering Interview Questions

60+ Mechanical Engineering Interview Question & Answer – For Freshers

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Posted by Aarna Tiwari Jan 31, 2024

Entering the world of mechanical engineering as a fresher is an exciting journey, but the path to success often involves navigating through challenging interviews. In this guide, we’ve curated a collection of common mechanical engineering interview questions along with detailed answers to help freshers prepare effectively.

Whether you’re aiming for a general mechanical engineering role, focusing on technical aspects, or holding a diploma, this guide has got you covered.

Table of Content

Common Mechanical Interview Questions For Freshers

Other than the common aptitude questions asked of engineering students, here are some common mechanical engineering interview questions for freshers along with their detailed answers:

  1. Can you explain the basic principles of thermodynamics? 

Thermodynamics is the branch of physics that deals with the relationship between heat, energy, and work. The basic principles of thermodynamics include the first law of thermodynamics, which states that energy cannot be created or destroyed, only transferred or converted from one form to another. The second law of thermodynamics states that the total entropy of a closed system will always increase over time. The third law of thermodynamics states that it is impossible to reach absolute zero temperature.

2. How do you determine the stress and strain in a material? 

Stress is the force applied per unit area, while strain is the deformation or change in shape of a material. To determine stress and strain in a material, one can apply basic engineering principles. By conducting tests like tension or compression tests, one can calculate stress and strain using formulas and analyze the material’s behavior.

3. Describe the different types of manufacturing processes you are familiar with. 

[As a fresher, you may not have hands-on experience with all types of manufacturing processes. However, you can describe the ones you are familiar with]. Some common manufacturing processes include casting, machining, forming, welding, and additive manufacturing (3D printing).

4. What CAD software are you proficient in? Can you describe a project where you utilized CAD?

CAD (Computer-Aided Design) software is used to create 2D and 3D models of products. As a fresher, I do not have extensive experience with CAD software.

5. Can you explain the difference between static and dynamic analysis?

Static analysis is used to analyze the behavior of a structure under a static load, while dynamic analysis is used to analyze the behavior of a structure under a dynamic load. In other words, static analysis is concerned with the forces acting on a structure when it is at rest, while dynamic analysis is concerned with the forces acting on a structure when it is in motion.

6. How do you ensure quality control in a manufacturing process? 

Quality control is an essential aspect of any manufacturing process. To ensure quality control, one can implement various techniques such as statistical process control, Six Sigma, and Total Quality Management. These techniques help to identify defects and improve the overall quality of the product.

7. Describe a time when you faced a design challenge and how you overcame it.

This question is designed to assess your problem-solving skills. You can describe a time when you faced a design challenge and how you overcame it. Be sure to highlight the steps you took to solve the problem and the outcome of your efforts.

8. What are the key factors to consider when selecting materials for a mechanical component?

When selecting materials for a mechanical component, some key factors to consider include the strength, stiffness, toughness, ductility, and corrosion resistance of the material. Other factors to consider include the cost, availability, and manufacturability of the material.

9. How would you approach a project that requires optimizing energy efficiency?

To optimize energy efficiency in a project, one can implement various techniques such as energy modeling, life cycle assessment, and energy audits. These techniques help to identify areas where energy can be saved and improve the overall energy efficiency of the project.

10. Can you explain the concept of tolerance analysis and its importance in mechanical engineering design?

Tolerance analysis is the process of determining the amount of variation that can be allowed in the dimensions of a mechanical component without affecting its performance. It is an essential aspect of mechanical engineering design as it helps to ensure that the product will function correctly under a range of conditions

Technical Mechanical Interview Questions With Answers

Check these 20 technical mechanical interview questions along with detailed answers for college students:

  1. What is the difference between stress and strain?

Stress is the force applied per unit area, while strain is the deformation or change in shape that occurs in a material due to stress. Stress is measured in Pascals (Pa), and strain is dimensionless.

2. Explain the working principle of a four-stroke engine.

A four-stroke engine goes through four phases: intake, compression, power, and exhaust. During the intake stroke, the fuel-air mixture enters the cylinder; in the compression stroke, the mixture is compressed; the power stroke is when the mixture is ignited, producing power; and the exhaust stroke expels the burnt gases.

3. What is the purpose of a flywheel in an engine?

A flywheel is used to store and release rotational energy, helping to maintain a steady and consistent speed of the engine by smoothing out variations in power output.

4. Differentiate between ductile and brittle materials.

Ductile materials can undergo significant deformation before rupture, whereas brittle materials tend to fracture without undergoing much deformation.

5. Explain the concept of thermal expansion.

Thermal expansion is the tendency of a material to change in size (expand or contract) in response to a change in temperature. Most materials expand when heated and contract when cooled.

6. What is the purpose of a gearbox in a vehicle?

A gearbox is used to provide variable speed and torque ratios between the engine and wheels, allowing the vehicle to operate efficiently at different speeds.

7. Describe the working principle of a hydraulic system.

A hydraulic system uses fluid to transmit power. When force is applied to a small piston, it creates pressure in the fluid, which is then transmitted to a larger piston, producing a larger force.

8. What is the significance of the Reynolds number in fluid mechanics?

The Reynolds number is a dimensionless quantity that characterizes the flow of a fluid. It helps predict the flow patterns, turbulence, and the transition between laminar and turbulent flow in pipes and channels.

9. Explain the purpose of a heat exchanger.

A heat exchanger transfers heat between two fluids, ensuring that they do not mix. It is commonly used in HVAC systems, refrigeration, and industrial processes to increase or decrease the temperature of a fluid.

10. What is the role of a governor in an engine?

A governor regulates the speed of an engine by controlling the fuel or power input based on the variations in load.

11. Differentiate between a closed cycle and an open cycle gas turbine.

In a closed-cycle gas turbine, the working fluid remains within the system, while in an open-cycle gas turbine, the working fluid is continuously taken in, expanded, and expelled.

Youngs Modulus

12. Explain the concept of Young’s Modulus.

Young’s Modulus is a measure of the stiffness of a material. It describes the ratio of stress to strain in a material under elastic deformation.

13. What is the purpose of a camshaft in an engine?

The camshaft is responsible for controlling the opening and closing of the engine’s valves. It has lobes that push against the valves, allowing the intake and exhaust processes to occur.

14. Discuss the Carnot cycle and its importance in thermodynamics.

The Carnot cycle is an idealized thermodynamic cycle that describes the maximum efficiency possible for a heat engine. It provides a benchmark for the efficiency of real-world heat engines.

15. Explain the difference between gear hobbing and gear shaping.

Gear hobbing is a process where a hob (cutter) is used to create gears, while gear shaping involves a shaper cutting tool to form gear teeth.

16. What is the function of a condenser in a refrigeration system?

A condenser in a refrigeration system is responsible for rejecting heat from the refrigerant to the surrounding environment, causing the refrigerant to change from a vapor to a liquid.

17. Describe the purpose of a pressure vessel.

Pressure vessels are designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They are used in various industries for storing and transporting compressed gases and liquids.

18. What is the purpose of a differential in an automobile?

The differential in an automobile allows the wheels to rotate at different speeds while providing equal torque. This is crucial when the vehicle is turning, preventing wheel skidding.

19. Explain the term ‘gauge pressure’ and how it differs from absolute pressure.

Gauge pressure is the pressure measured above atmospheric pressure, while absolute pressure includes atmospheric pressure as a reference point. Gauge pressure is zero when the pressure is equal to atmospheric pressure.

20. Discuss the concept of entropy in thermodynamics.

Entropy is a measure of the disorder or randomness in a system. In thermodynamics, it is associated with the amount of energy in a system that is no longer available to do work. Systems tend to evolve towards higher entropy states.

‘Difference Between’ Mechanical Engineering Question Answers

Many times, during the mechanical interview, questions related to differences are asked to students to understand their conceptual clarity regarding the topic. We have compiled a list of these types of questions to help students with their upcoming interviews.

  1. What is the difference between a force and a torque?

A force is a push or pull on an object that causes it to move in a straight line, while a torque is a rotational force that causes an object to rotate around an axis.

2. What is the difference between a closed system and an open system?

A closed system is a system that does not exchange matter with its surroundings, while an open system is a system that can exchange matter with its surroundings.

3. What is the difference between a thermoplastic and a thermosetting plastic?

Thermoplastics can be melted and re-molded multiple times, while thermosetting plastics cannot be melted and re-molded once they have been formed.

4. What is the difference between a bolt and a screw?

A bolt is a fastener that requires a nut to secure it in place, while a screw is a fastener that can be screwed directly into a material without the need for a nut.

5. What is the difference between a centrifugal pump and a positive displacement pump? 

A centrifugal pump uses a rotating impeller to move fluid through the pump, while a positive displacement pump uses a mechanical means to move fluid through the pump.

6. What is the difference between a two-stroke engine and a four-stroke engine?

A two-stroke engine completes a power cycle in two strokes of the piston, while a four-stroke engine completes a power cycle in four strokes of the piston.

types of Bearings

7. What is the difference between a bearing and a bushing? 

A bearing is a machine element that reduces friction between moving parts, while a bushing is a machine element that provides a bearing surface for rotary applications.

8. What is the difference between a gear and a sprocket? 

A gear is a rotating machine element that transmits torque, while a sprocket is a toothed wheel that engages with a chain to transmit torque.

9. What is the difference between a pneumatic system and a hydraulic system? 

A pneumatic system uses compressed air to transmit power, while a hydraulic system uses a liquid such as oil to transmit power.

10. What is the difference between a worm gear and a spur gear? 

A worm gear is a type of gear that has a screw-like shape, while a spur gear is a type of gear that has straight teeth.

11. What is the difference between a ductile material and a brittle material? 

A ductile material can be deformed without breaking, while a brittle material will break when subjected to stress.

12. What is the difference between a lap joint and a butt joint? 

A lap joint is a joint where two pieces of material overlap, while a butt joint is a joint where two pieces of material are joined end-to-end.

13. What is the difference between a static load and a dynamic load? 

A static load is a load that does not change over time, while a dynamic load is a load that changes over time.

14. What is the difference between a cantilever beam and a simply supported beam? 

A cantilever beam is a beam that is fixed at one end and free at the other end, while a simply supported beam is a beam that is supported at both ends.

15. What is the difference between a compression spring and a tension spring? 

A compression spring is a spring that is designed to resist compression, while a tension spring is a spring that is designed to resist tension.

16. What is the difference between a lap winding and a wave winding? 

A lap winding is a winding where the end of one coil is connected to the beginning of the next coil, while a wave winding is a winding where the end of one coil is connected to the beginning of the next coil through a third coil.

difference between a synchronous motor and an asynchronous motor

17. What is the difference between a synchronous motor and an asynchronous motor? 

A synchronous motor rotates at a constant speed that is synchronized with the frequency of the power supply, while an asynchronous motor rotates at a speed that is slightly less than the synchronous speed.

18. What is the difference between a reciprocating compressor and a centrifugal compressor? 

A reciprocating compressor compresses gas by using a piston that moves back and forth, while a centrifugal compressor compresses gas by using a rotating impeller.

19. What is the difference between a single-stage compressor and a multi-stage compressor? 

A single-stage compressor has one set of plates and valves, while a multi-stage compressor has more than one set of plates and valves where each set is connected with another via some sort of connecting mechanism.

20. What is the difference between a heat pump and an air conditioner? 

A heat pump is a device that can both heat and cool a space, while an air conditioner is a device that only cools a space. Heat pumps work by transferring heat from

Diploma in Mechanical Engineering Interview Questions

With the different types of mech engineering questions answered above, students should also practice common interview questions for their placement sessions. It helps them build confidence.

  1. Explain the concept of entropy in thermodynamics and its practical applications.

Entropy is a measure of the disorder or randomness in a system. In thermodynamics, it represents the unavailability of a system’s energy for work. Practical applications include heat engine efficiency, refrigeration cycle performance, and understanding irreversible processes.

2. What are the main types of materials used in engineering and their properties?

Engineering materials include metals (e.g., steel, aluminum), polymers (e.g., plastics), ceramics, and composites. Each material type has unique properties, such as conductivity, strength, and durability, making them suitable for specific applications.

3. How does heat treatment affect the properties of metals? Give examples.

Heat treatment alters the microstructure of metals, influencing their mechanical properties. Annealing, for example, reduces hardness and increases ductility. Hardening processes like quenching increase hardness. Tempering balances hardness and toughness.

4. What is the importance of fluid mechanics in mechanical engineering, and provide an example of its application?

Fluid mechanics studies the behavior of fluids (liquids and gases). It’s crucial in designing pumps, turbines, and aerodynamics. An example is the design of aircraft wings to optimize lift and drag forces.

5. Discuss the role of bearings in machine design and their different types.

Bearings reduce friction between moving parts. Types include ball bearings, roller bearings, and plain bearings. Proper selection is vital for load distribution, durability, and efficiency.

6. What is the significance of the modulus of elasticity in materials?

The modulus of elasticity (Young’s Modulus) measures a material’s stiffness. It relates stress to strain and is crucial in designing structures to withstand deformation.

7. Explain the basic principles of thermoelectric power generation.

Thermoelectric power generation utilizes the Seebeck effect, converting a temperature difference between two materials into an electric voltage. It finds applications in waste heat recovery and portable power sources.

8. Describe the applications and advantages of CNC machining in manufacturing.

CNC machining (Computer Numerical Control) provides precise, automated control of machine tools. It’s used in manufacturing for high-precision components, improving accuracy, repeatability, and efficiency.

9. What is the purpose of a heat exchanger, and how does it work?

A heat exchanger transfers heat between two fluids without them mixing. It finds applications in HVAC, refrigeration, and industrial processes. Heat exchange occurs through conduction or convection, depending on the exchanger type.

10. How does Finite Element Analysis (FEA) contribute to the design process in mechanical engineering?

FEA simulates the behavior of structures under various conditions. It aids in predicting stress, deformation, and failure, allowing engineers to optimize designs before physical prototypes are built.

11. Explain the significance of tolerance and clearance in engineering drawings.

Tolerance defines permissible variation from specified dimensions. Clearance ensures parts fit together correctly. Both are critical for manufacturing precision and assembly.

12. Describe the importance of safety considerations in mechanical engineering and provide examples of safety measures in a workshop environment.

Safety is paramount in mechanical engineering. Examples include wearing personal protective equipment (PPE), implementing lockout/tagout procedures, and proper training to prevent accidents and injuries in a workshop environment.


In conclusion, excelling in mechanical engineering interviews as a fresher requires a combination of fundamental knowledge, technical proficiency, and practical experience. By mastering common, diploma-specific, and technical interview questions, you can confidently showcase your skills and stand out among other candidates.

Mechanical Engineering Interview Questions PDF

Remember to tailor your responses to highlight your unique experiences and problem-solving abilities.

Related Reads:

FAQs on Mech Engineering Questions

What are the questions asked in an interview for a mechanical engineer?

In a mechanical engineer interview, common questions include topics like thermodynamics, mechanics, and problem-solving. Employers may inquire about your experience, technical skills, and ability to handle real-world challenges in the field.

What are the basic mechanical questions?

Basic mechanical questions cover fundamental principles like Newton’s laws, fluid dynamics, and material science. These inquiries assess a candidate’s grasp of core mechanical concepts, providing insight into their foundational knowledge.

Is mechanical engineer interviews hard?

Mechanical engineer interviews can be challenging due to the diverse technical and problem-solving aspects. Expect questions on engineering principles, practical applications, and your ability to tackle complex issues, demonstrating both theoretical and hands-on expertise.

How to pass a mechanical engineering interview?

To succeed in a mechanical engineering interview, prepare by reviewing key concepts, practicing problem-solving, and showcasing your practical skills. Emphasize your experience, communicate effectively, and demonstrate a passion for innovation in the field to leave a lasting impression.

What are the 5 things mechanical engineers do?

Mechanical engineers engage in designing, analyzing, and improving mechanical systems. Their tasks range from creating blueprints, conducting simulations, and overseeing manufacturing processes to troubleshooting issues and optimizing machinery for enhanced performance and efficiency.

Who is the world’s most popular mechanical engineer?

While opinions vary, Nikola Tesla is often regarded as one of the world’s most renowned mechanical engineers. His contributions to electromagnetism, alternating current systems, and numerous inventions have left an indelible mark on the field, solidifying his status as an iconic figure in mechanical engineering history. Other notable ones include George Stephenson, James Watt, Rudolf Diesel, and Bill Nye.


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