Civil Engineering Interview Questions And Answers

Latest Job Interview Questions And Answers

Q.1 What is meant by elastic limit? 

Ans. The maximum extent to which a solid may be stretched without permanent alteration of size or shape.

Q.2 What is the difference between BC and SDBC ?

Ans BC- Bituminous Concrete
SDBC- Semi Dense Bituminous Concrete

Q.3 What is the basic difference in absorption, adsorption, and sorption?

Ans.Absorption is a phenomenon where an atom, molecule particle or ions enter any bulk phase like gas, solid or liquid. Absorption refers to the phenomenon where energy of photon is transferred to other entity.
Adsorption is quite same to absorption. It refers to the surface rather than a volume. Adsorption occurs when the gas or liquid solute accumulates on the surface of solid. A substance diffuses or mixed in liquid or solid to form a solution.

Q.4 What is the meaning of Fe415 ?
Ans Fe415 rafers for Ferrous material ie iron from which the reinforcement steel bars are manufactured. The number 415 indicates that the Yield Strength (tensile strength when it is subjected to elongation) of steel is 415 N/mm2.
The reinforcement steel bars used in RCC (Reinforced Cement Concrete) are designated in grades of Fe250, Fe415 or Fe500 depending on their Yield Strength.

Q.5 How are the freeway bridges built?
Ans.The traffic that is likely to go over the bridge at a time is estimated and the cement, rocked with rubber stanchions is placed over the freeway to build a bridge. Off-ramp from freeway to the bridge and on-ramp from the bridge to the freeway are constructed. Cement slabs are placed one by one to build a platform.

Q.6 A flat slab is capable to withstand ?
Ans..concentrated loads.

Q.7 An R.C.C. column is treated as long if its slenderness ratio is greater than?
Ans..50

Q.8 Difference between routine maintenance and major maintenance for school facilities?

Ans..Routine maintenance is handling the minor repairs of the school campus. Major maintenance can be total reconstruction or renovation of the school.

Q.9 Cantilever retaining walls can safely be used for a height not more than?
Ans..6 m

Q.10 State the applications of modulus of elasticity?

Ans...Modulus of elasticity is related to the flexibility of the material. The value of modulus of elasticity is pretty important in case of deflection of different materials used in building construction.

Q.11 The minimum number of main steel bars provided in R.C.C.?
Ans. .rectangular columns is 4
circular columns is 6
octagonal columns is 8

Refrigeration & Air-Conditioning Questions And Answers

Refrigeration & Air-Conditioning Questions And Answers

Q. The COP of a Carnot refrigeration cycle decreases on what?

Ans. Increasing the upper temp. and decreasing the lower temp.

Q. The correct sequence of vapour compression(VC) Vapour Absorption(VA) and Steam Injection(SE) refrigeration cycles in increasing order of the COP is....

Ans. VA, SE, VC

Q. Flash chamber is used in refrigeration for which one of following?

Ans. Effective inter cooling medium for purpose of increasing COP

Q. The significant advantage of using Ammonia as a refrigerant is its

Ans High Latent Heat

Q. Which refrigerant mostly used in mostly all domestic and car air-conditioners now a days

Ans. R-134a

Q. The color of the flame of halide torch,in a case of leakage of Freon refrigerant,will change to...

Ans. Orange

Q. Which refrigerant has the highest critical temperature?

Ans. Water

Q. In on-off control refrigeration system, which one of the following expansion device is used?

Ans. Thermostat
Interim Dividend

Q. Which is the main process which takes place in a desert-cooler?

Ans.Adiabatic Saturation

Q. If the measured wet-bulb temperature and the thermodynamic wet-bulb temp.are equal, then the non dimensional number with a value of unity is...

Ans. The Lewis Number

Q. In an ideal vapour compression refrigeration cycle, the enthalpy of the refrigerant before and after the evaporator are respectively 75 KJ/KG and 180 KJ/KG. The circulation rate of the refrigerant for each of refrigeration is....?

Ans. 2 kg/min

Q. When the mixture of refrigerant is used to replace a refrigerant , if the cop increase, the attributed is..

Ans. Increase in cooling effect

Q. Which of the following thermodynamic process is adopted in the process of summer air-conditioning?

Ans. Cooling and de humidification

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Thermodynamics Questions And Answers

Q. What is the fundamental unit of enthalpy?

ML²T^-2

Q. If integration pdv and -pdv for a thermodynamic system of an ideal gas on evaluation give the same quantity during a process, then the process undergone by the system is...

Isothermal

Q. In a steam condenser the partial pressure of steam and air are 0.06 bar and 0.007 bar respectively the condenser pressure is...

0.067 bar

Q. Which law of thermodynamics will be violated, if the thermal efficiency of an engine becomes 100%

Second Law

Q. The change in enthalpy of a closed system is equal to the heat transferred, if the reversible process takes place at constant?

Pressure

I.C. Engine Questions

Q. Air standard diesel cycle a compression ratio 14 and cut off takes place at 6% of the stroke. What is the cut off ratio?

Ans. 1.78

Q. Consider the following:

1 Increased Cetane Number

2 Increased compression ratio

3 Increased injection Advance

4 Increased air Turbulence

Which of the above factors reduces physical delay in the diesel engine?

Ans. 2 and 4 only

Q. Consider the following:

Diesel engine knock can be reduced by increasing

1 Engine Speed

2 Compression Ratio

3 Degree of Supercharge

4 Injection Advance

Which of the above statement is/are correct?

Ans. 2 and 3

Q. Self ignition temp. of diesel as compare to petrol is?

Ans. Lower

Q. For a four cylinder vertical engine, the commonly used firing order is...

Ans. 1-3-4-2

Mechanical Engineering Interview Questions And Answers

Mechanical Engineering Interview Questions

Q 1. What is the difference between Technology and Engineering?

Ans. Engineering is 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 shows different technology but comes under civil engineering and science applied is laws of force/load distribution.

Q. 2 What is the difference between tensile strength and tensile modulus?

Ans. Tensile Strength:-

It is the ultimate capacity of the material to resist the tensile load regardless of deflection.

Tensile Modulus:-

It is the measure of the stiffness of an isotropic elastic material. It is also called asYoung Modulus.

. It is defined as the ratio of the uni-axial stress over the uni-axial strain.

Q. 3 What is the difference between shear Strength and tensile strength?

Ans. Tensile strength is the strength in tension on the application of pulling force while shear strength is the strength against cutting shear force.

Q. 4 What is Mechanical Engineering?

Ans. Mechanical engineering is a branch of engineering in which we apply physics laws along with material science to accelerate the human process.

Q. 5 What is the difference between Yield Stress and Yield Strength?

Ans. Stress is a measure of internal resisting force(load) applied on a body per unit area.While Strength is a quantification of the ability to carry the load.

Yield stress and Yield strength of a material usually used as interchangeable according to the application of load. If load is low we will use yield stress but if load will be vary high we will use yield strength.

Q. 6 What is the honing of cylinder liners?

Ans. "Chris Marine"is the manufacturer of honing equipment.

The head of the honing device consists of four synchronized stones.

For the initial honing diamond stones are used to break up the hardened surface in the scuffed areas.

For the main honing very coarse and hard stones are used to produce a very desirable rough surface all over the liner.

The advantage, especially for the 2-stroke engines, is possibility to save the liner after a seizure, scuffing or blow-by or even to eliminate the ovality of the liner.

Another advantage is that it is possible to machine a rough liner wall to obtain a well oiled surface.

Q. 7 What type of cooling you will prefer for a 3-cylinder engine system?

Ans. Multi-Cylinder Engines are used for heavy load cosideration. So it is a heavy duty engine. We will prefer liquid or water cooling system for a 3-cylinder engine system.

Q. 8 What is the difference between weight and mass?

Ans. Mass is the measure of amount of matter that a body or object contain. It is measured in Gram or KG. Mass of a body remains constant in the whole universe.

Weight is the measure of force that how strongly gravity pulls to that matter. It is measured in kilogram meter per second square. Weight will be changed according to the change in gravitational acceleration.

Q. 9 Differentiate the terms center of mass and center of gravity.

Ans. Each body is made by small-small particles. These particles contains some mass also.

Center of mass of a body is a point where all the masses of particles are centered.

Center of gravity of a body is a point where the vector some of all the gravitational forces will act.

If gravity is uniform then both center of mass and center of gravity will be SAME.

Q. 10 Why I-section beam is preferred for heavy loading?

Ans. It provides less deformation on the application of load and it withstand higher bending moments on comparison of other shapes of the beam. It is easy to manufacture.

Q. 11 Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?

Ans. The Positive Displacement pump has more or less constant flow regardless of pressure while centrifugal pump has varying flow depending upon pressure or head.

Viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency.

Q. 12 Why the centrifugal pump is called high discharge pump?

Ans. Centrifugal pump is a kinetic device.

The centrifugal pump uses the centrifugal force to push out the fluid. So the liquid entering the pump receives kinetic energy from the rotating impeller.

Due to centrifugal force the impeller accelerates the liquid to a high velocity, transferring mechanical energy to the liquid. So it discharges the liquid in high rate.

13. Why is stress considered important in a shaft?

The following types of stresses are prevalent in shafts:

1- At the outermost surface of the shaft the max shear stress occurs on the cross-section of the shaft.

2-At the surface of the shaft on the longitudinal planes through the axis of the shaft the maximum longitudinal shear stress will occurs.

3- At 45 degrees to the maximum shearing stress planes at the surface of the shafts the major principal stress occurs. It equals the maximum shear stress on the cross section of the shaft.

4- For certain materials where the tensile and compressive strengths are lower in measure as compared to the shear strength, then the shaft designing should be carried out for the lowest strengths.

5- All these stresses are of significance as they play a role in governing the failure of the shaft. All theses stresses get generated simultaneously and hence should be considered for designing purposes

Q. 14 Why don't we use a single turbine of required power instead multiple turbines in hydro power stations?

Ans. It is difficult to work with a single turbine than multiple turbines because the exhaust of one turbine is used as input two second turbine.so work input becomes less for multiple turbines than a single turbine for doing greater work.that why we find multiple turbines for power generation in dams.

Q. 15. What are the types of bearing on the basis of friction?

Ans. There are two types of bearing.

1. Friction Bearing 2. Anti Friction Bearing

Q. 16 What is the difference between heat pump and heat engine ?

Ans. HEAT ENGINE IS A DEVICE WHICH PRODUCES WORK WHILE TRANSFERRING HEAT FROM HIGHER TEMP. TO LOWER TEMP. WHEREAS IN HEAT PUMP WORK IS NEED TO SUPPLY TO TRANSFER HEAT FROM LOWER TEMP. TO HIGHER TEMP.

Q. 17 What are the best materials for gears?

Ans. Cast iron it has great impact strength and also self lubrication and phosphorus bronze is also better for gears.

Q. 18 Where is fixed a Governer in automobile?

Ans. Governer is a device which is used to regulate speed of an engine. Mostly a centrifugal governor is used in an automobile, when the speed is high height of its arms increases thus decreasing the area... which in turn allows more fuel to enter and vice versa.

Q. 19 Why gate valve is not suitable for throttling?

Ans. Gate valve is not suitable for throttling because it is difficult to control the flow due to valve design.And flow of fluid can be caused for the damage of the valve.

Q. 20 Describe mechanical engineering in your own words.

Ans. Mechanical engineering is one of the largest and broadest fields of technical study.

Mechanical engineers are concerned with the engineering systems used to control and transform energy to meet the needs of humanity.

In mechanical engineering, students develop an understanding of basic topics and fundamental principles upon which engineered systems are conceived and developed in a modern society.

It is an excellent foundation for a rewarding career in engineering, as well as for further study in business, law, medicine, and other professions that require a solid foundation in science and technology, and the ability to solve problems.