Latest Mechanical Updates

01-Technical Interview questions-how to prepare for technical interview-job interview-getting a job

  • What is the Material composition in IBR tubes?

Carbon max………………… 0.10%

Manganese max……………. 0.60%

Nickel max…………………. 0.25%

Sulphur max………………… 0.050%

Phosphorus max…………….. 0.050%

  • What is the difference between P11 & P22 pipes?

P11 the chromium molybdenum composition that is 1% ofchromium and 1/4% of molybdenum

P12 the chromium molybdenum composition that is 1% ofchromium and 2% of molybdenum

  • 1st law of Thermodynamics



  • Difference between Unilateral tolerance and Bilateral tolerance

A unilateral tolerance is tolerance in which variation is permitted only in one direction from the specified direction.e.g. 1800 +0.000/-0.060

Bilateral tolerance is tolerance in which variation is permitted in both direction from the specified direction.e.g. 1800 +0.060/-0.060

  • Why we need two angle of projections ( 1st angle and 3rd angle)? Cant we standardize to one.

Generally 1 St. angle followed in India and 3rd angle projection is used in European countries. In 1st and 3rd angle projections there is no overlapping of principal planes while drawing side and top views. but in 2nd and 4th angle projections the principal planes are overlapped while drawing top and side views. It results confusion in drawing. For this reason 1st and 3rd angle projections are used commonly.

  • During which of the following processes does heat rejection takesplace in carnot vapour cycles
    1. Constant volume
    2. Constant pressure
    3. Constant temperature
    4. Constant entrophy


Constant Temperature

  • What is the difference between Corrective actions and preventive actions?

Corrective actions are taken on discrepancies noticed duringinspection of products/documents/process whereas preventiveactions are taken to eliminate the possibility ofdiscrepancy in future.

  • What is the Shaft coupling and its types

It is used to join two shafts for transmission motion from one shaft to another shaft,it may be either flexible or rigid type.

Rigid coupling;(Muff coupling, Flange coupling, Marinecoupling, Oldham”s coupling)Flexible coupling;(Flexible bush pin coupling)

Oldham’s Coupling is used when axis of shaft are not aligned

Other types are:

loveys joy coupling

Spider coupling

Tyre coupling

Pin and bush coupling

Fluid coupling

Vulcan coupling

Flexible coupling

Universal coupling

Articulate joints

  • What is meant by One ton Air conditioner, how fast it cool a room.

1 ton refrigeration means 210 kJ/min extracts heat from thesystem.

  • Boyle’s law

Boyle’s law describes the inversely proportional relationship between the absolute pressure and volume of a gas.

  • When temperature increases the frequency of the tuning fork
    a. Increases
    b. Decreases
    c. Remain same
    d. Increases or decreases depending on the material

B. Decreases

  • What happens in the float chamber during the idling action of the fuel pump
    a. It remains empty
    b. It remains partially filled
    c. It remains filled
    d. None

C. It remains filled

During idling period, no petrol is drawn from the carburettor and the float inside the float chamber floats exerting pressure on the fluid as a result of which the inflow of the fuel to carburettor is stopped.

  • The exact analysis of viscous flow problems can be made by
    a. Euler’s equation
    b. Hagen poiseuille’s equation
    c. Continuity equation
    d. Navier-stroke’s equation

D. Navier – stroke’s equation

Latest Updates in Mechanical Engineering

01-job-interview-easy selection in interview

  • 1hp=how much rpm

We need Torque to find out.

Apply this formula:

T = HP x 5252

T = torque (in lb-ft)
HP = horsepower
5252 = constant
rpm = revolutions per minute

  • which mechanism is used in automobile gearing system

Differential mechanism

  • why different types of sound are produced in different bikes though they say run on SI engine

Engine specifications are different in different manufactures like as bore diameter(cc),ignition timing.Also the exhaust passage take more responsible for sound.

  • why entropy decreases with the increase in temperature?


Entropy is inversely proportional to the temperature temp. increases,entropy decreases

  • What type of metal is used in a propeller

Aluminium,stainless steel,magnesium bronze,NIBRAL(nickel,brass,aluminium)

  • why involute curve used in gear

1) it’s smooth to drive the gear.
2) in gears contact is only point, this type is curve take the more load than normal one

  • How Trains take turns, though there is no any differential

Purpose of the differential is to enable vehicles to take turn, by allowing both the wheel to rotate with different speed. This is required when wheels, like in car, are connected with same axle. Interestingly, wheel in trains are not connected with the axle, they are independent and hence can take turns without ant differential. This is same as how the bullock cart takes turns, without any differential.

  • In condensation of steam power plant, steam sent in shell side and cooling water on the tube side because
    1. To increase overall heat transfer coefficient of water side velocity can be increases if water is on the tube side
    2. Condenser can act as a storage unit for condensed steam
    3. Rate of condensation of steam is invariably smaller than the mass flow rate of cooling water
    4. It is easier to maintain vacuum on the shell side than on the tube side


1. To increase overall heat transfer coefficient of water side velocity can be increases if water is on the tube side


Specific volume of steam is larger so more volume is required in condenser

  • Why freezer in the fridge is placed in top level?

Because density of cold air is higher than warm air,hence itis placed at top.Cold air comes downward & cool the bottom part.

  • what is more dangerous longitudinal stress or Hoop stress and why?

Hoop stress is more dangerous thanlongitudinal stress, because the dangerous area coming underthe hoop stress is circumferential,while in longitudinal,theaxial area will come under dangerous area will will be lessthan circumferential area.So the hoop stress is more dangerous than longitudinal stress

  • In a spray washing system, if the water temperature is higher than the dry bulb temperature of entering air then the air is
    1. Heated and dehumidified
    2. Heated and humidified
    3. Cooled and humidified
    4. Cooled and dehumidified


Heated and humidified

1 2