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Mechanical Engineer Job Interview Questions

Mechanical Engineer Job Interview Questions


Difference between technology & engineering?

Engineering is an application of science. Technology shows various methods of Engineering. A bridge can be made by using beams to bear the load, by an arc, or by hanging in a cable; all show different technology but comes under civil engineering, and science applied is laws of force/load distribution.

How a diesel engine works in the generator?

The diesel engine is a prime mover, for a generator, pump, and for vehicles, etc.generator is connected to the engine by the shaft. mostly in thermal power plants, there is an engine is used to drive the generator to generate power.


Micrometer’s other name is Screw Gauze & Vernier caliper’s other name is slide caliper.

What is a flashpoint?

Flash point: the lowest temperature at which the vapor of a combustible liquid can be ignited in air.

What is the basic difference between an impulse turbine and a reaction turbine?

In an impulse turbine, jet is used to create impulse on blades which rotates the turbine and in a reaction turbine, no jet is used pressure energy is converted into kinetic energy.

In impulse turbine fluid enter& leave with the same energy, but in reaction turbine fluid enter with pressure energy & leaves with kinetic energy

In the impulse turbine, all the pressure drops in the nozzle only & in the reaction turbine pressure drops on both fixed & moving blades. The difference is due to blade profiles.

What is the need for drafting?

Drafting is the allowance given to the casting also used to remove the casting from mould without damage of corners.

What is the difference between BSP thread and BSW thread?

The British Standard Pipe thread (BSP thread) is a family of standard screw thread types that has been adopted internationally for interconnecting and sealing pipe ends by mating an external (male) with an internal (female) thread. British Standard Whitworth (BSW) is one of a number of imperial unit-based screw thread standards that use the same bolt heads and nut hexagonal sizes.

What is refrigerant?

Any substance that transfers heat from one place to another, creates a cooling effect. water is the refrigerant in absorption machines.

The amount of carbon present in Cast Iron

Carbon is basically present in the form of cementite in cast iron. Its percentage lies in the range of 2.03-6.67(% by weight of cementite for Cast Iron. If the amount is less than the above range then it is stainless steel.

What are the loads considered when designing the Nut and Bolts?

Shear Loads & crushing loads

The main purpose of the fan of a liquid cooling system for an engine is to

  1. Disperse engine fumes
  2. Cool the external surfaces of the engine
  3. Pump hot air over the cold cooling water
  4. Give an airflow when the vehicle speed is low


  1. Give an airflow when the vehicle speed is low


The fan is a forced cooling system. The fan throws air on the liquid continuously which forcibly dissipates the heat gained by the liquid.

What is the effect of reheat on Rankine cycle?

  1. Efficiency increases

  2. Work output increases

  1. both
  2. none of these.


  1. Efficiency increases.


p align=”justify”>Reason:

This prevents the vapor from condensing during its expansion which can seriously damage the turbine blades, and improves the efficiency of the cycle, as more of the heat flow into the cycle occurs at the higher temperatures.

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