# Mechanical Engineering Career Information | Mechanical Engineering Interview Questions

• What is Heat rate of a Power plant?

Heat rate is a measure of the turbine efficiency. It is determined from the total energy input supplied to the Turbine divided by the electrical energy output.

• The highest value of Thermal conductivity is expected for

a.) Solid ice   b.) Melting ice c.) Water d.) Boiling water.

Give the Thermal conductivity value.

Solid Ice – 3.48 W/mK

Melting Ice thermal conductivity value is low because temperature is less.

Water’s Thermal conductivity value is 2.18 W/mK.

• What is a Hydrostatic system?

Hydrostatics is the study of ﬂuid bodies that are

• At rest
• Moving suﬃciently slowly so there is no relative motion between adjacent parts of the body

For hydrostatic situations

• There are no shear stresses
• There are only pressure forces that act perpendicular to any surface.

It’s a closed loop hydraulic systems. It comprises of motor and pump. Here pump supplies energy to motor and motor gives return energy to pump supply.

• If you heat a piece of steel with a hole in the center will the diameter of the steel get bigger or smaller?

It gets bigger.

(Example: Always the bearings are heated first for new installation in a shaft.)

• What is the difference between Blower and Fan?

Fan is an air pushing device. Either Axial or Centrifugal type systems are used to move the air in low pressure. It is rotated by a motor separately.

When the fan is a housing of blades and motor, then it called as Blower. It directs the air in a single path with high pressure.

• How to find a Ductile-Brittle Transition Temperature in metals?

The point at which the fracture energy passes below a pre-determined point for a standard Impact tests. DBTT is important since, once a material is cooled below the DBTT, it has a much greater tendency to shatter on impact instead of bending or deforming.

• What is Hydrodynamic Cavitation?

Hydrodynamic cavitation describes the process of vaporization in a constrained channel at a specific velocity.

Bubble generation and Bubble implosion which occurs in a flowing liquid as a result of a decrease and subsequent increase in pressure.

# Latest Mechanical Engineering Interview Questions | Entry Level Mechanical Engineering Jobs Interview Questions

1) Difference between Performance and Efficiency?

· The accomplishment of a given task measured against preset known standards of accuracy, completeness, cost, and speed is called as Performance.

· Efficiency is defined as the input given and the work obtained from that input like money, time, labour etc. It’s the main factor of productivity.

2) What is the difference between Impact Force & Sudden Force?

· An impact is a high force or shock applied over a short time period when two or more bodies collide.

· A force which applies on the body (material) suddenly is known as sudden force.

3) Difference between Antifriction Bearing and Journal Bearing

Generally, journal bearings have higher friction force, consume higher energy and release more heat, but they have larger contact surface, so normally used in low speed high load applications. In anti friction bearings friction is less.  One object just rolls over each other.

4) What is a Cotter joint?

A cotter joint is used to connect rigidly two co-axial rods or bars which are subjected to axial tensile or compressive forces. Here shaft is locked in place by a smaller pin that passes through the side of the lug and partly or completely through the shaft itself. This locking pin is named as cotter.

5) What is difference between Hardness and Toughness?

· Toughness is the ability of a material to absorb energy.

· Hardness is the ability of a material to withstand wear.

6) What is the difference between Toughness, Hardness and Strength?

· Toughness is the ability of a material to absorb energy.

· Hardness is the ability of a material to withstand wear.

· Strength is generally withstanding stresses, fatigue etc.

7) What is the difference between Strength and Stamina?

· Strength is capability over a short length of time.

· Stamina is the ability to keep going continuously.