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DMRC 2021 Interview Questions and GD Tips

Updated On -

Oct 6, 2020

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Akanksha Gupta

Content Curator

The Delhi Metro Rail Corporation (DMRC) is one of the biggest railway network connectivity. DMRC Interview and Group Discussion for Assistant Manager (Civil)  will be declared once the recruitment notifiation is issued. Also, check Exam dates of DMRC 2021

It is the final round of selection in DMRC. Delhi Metro Rail Corporation (DMRC) is one of the government sectors which select the candidate on the basis of the performance of the interview. Each field (Mechanical, Electronics, Civil) in DMRC Recruitment has different questions in interview, on the basis of which the candidates score marks in this round.

Before proceeding to the questions asked in the interview, here is the job profile of Assistant Manager. Knowing these can help the candidate to understand better how to act in the interview.

Suitable manager at DMRC should have the mentioned key abilities:

Can not only talk, but also listen.

Be a good listener. Try to prove this. Don’t try to prove that you everything and all the people just have to listen to your orders, also listen to what others say.

Should be a good example to his sub-ordinates.

You should take on projects by yourself, be actively involved in things happening in the workplace, don’t just sit in the office.

Be willing to take decisions, hire but also fire if it is needed.

Manager should not let his emotions to influence his decisions. Take decision based on the answer to that question or solution to that conflict.

Interview Questions

Few questions related to different branches are discussed below; candidates can have a look for before going to the interview:

DMRC Assistant Manager Interview Questions (Mechanical)

Explain the second law of thermodynamics.

Everything that happens is caused by an energy change. Energy changes form, or moves from place to place.

Energy changes are the driving force of the universe. The driving force of all energy change is the unstoppable tendency of energy to flow from high concentrations of energy to lower concentrations of energy.

Example: When it comes to doing useful work like running or powering a car, highly concentrated energy is easier to use and more efficient than low concentrations of energy.

What kinds of pipes are used for steam lines?

Normally galvanized pipes are not used for steam. Pressure and temperature are very important factors to be considered in what type of materials to be used. Steam even at low pressures can be extremely dangerous.

What is a cotter joint?

These types of joints are used to connect two rods, which are under compressive or tensile stress. The ends of the rods are in the manner of a socket and shaft that fit together and the cotter is driven into a slot that is common to both pieces drawing them tightly together.

What is the alloy of tin and lead?

A tin and lead alloy is commonly called solder. Usually solder is a wire with a rosin core used for soldering. The rosin core acts as a flux. 

What is the difference between shear center flexural center of twist and elastic center?

The shear center is the centroid of a cross-section. The flexural center is the center of twist, which is the point on a beam where you can add a load without torsion. The elastic center is located at the center of gravity. If the object is homogeneous and symmetrical in both directions of the cross-section then they are all equivalent.

What is the difference between projectile motion and a rocket motion?

A projectile has no motor/rocket on it, so all of its momentum is given to it as it is launched. An example of a projectile would be pen that you throw across a room.
A rocket or missile does have a motor/rocket on it so it can accelerate itself while moving and so resist other forces such as gravity.

What does F.O.F. stand for in piping design?

FOF stands for Face of Flange.

The F.O.F is used to know the accurate dimension of the flange in order to avoid the minute errors in measurement in case of vertical or horizontal pipelines.

Explain Otto cycle.

Otto cycle shows the functioning cycle of a four stroke engine. The cycle starts with an intake stroke, closing the intake and moving to the compression stroke, starting of combustion, power stroke, heat exchange stroke where heat is rejected and the exhaust stroke.

What is a uniformly distributed load?

A UDL or uniformly distributed load is a load, which is spread over a beam in such a way that each unit length is loaded to the same extent.

What is the alloy of tin and lead?

A tin and lead alloy is commonly called solder. Usually solder is a wire with a rosin core used for soldering. The rosin core acts as a flux.

What is gear ratio?

It is the ratio of the number of revolutions of the pinion gear to one revolution of the idler gear.

What is ductile-brittle transition temperature?

It is the temperature below which the tendency of a material to fracture increases rather than forming. Below this temperature the material loses its ductility. It is also called Nil Ductility Temperature.

What are the differences between pneumatics and hydraulics?

  • Working fluid: Pneumatics use air, Hydraulics use Oil
  • Power: Pneumatic power less than hydraulic power
  • Size: P components are smaller than H components
  • Leakage: Leaks in hydraulics cause fluid to be sticking around the components. In pneumatics, air is leaked into the atmosphere.

What are the advantages of gear drive?

In general, gear drive is useful for power transmission between two shafts, which are near to each other. It has maximum efficiency while transmitting power. It is durable compare to other such as belts chain drives etc.


  • It increases fuel efficiency.
  • It is used to get various speeds in different load conditions.
  • Increases engine efficiency.
  • Need less power input when operated manually.

Why gas containers are mostly cylindrical in shape?

The most efficient shape for withstanding high pressure is a sphere but that would be costly to manufacture. A cylinder with a domed top and a domed bottom is a much cheaper shape to manufacture whilst still having good strength to resist the internal gas pressure.

Can you use motor oil in a hydraulic system?

Hydraulic fluid has to pass a different set of standards than motor oil. Motor oil has tackifiers, lower sulfur content, and other ingredients that could prove harmful to the seals and other components in a hydraulic system. If it is an emergency only then should you do it.

What is the role of nitrogen in welding?

Nitrogen is used to prevent porosity in the welding member by preventing oxygen and air from entering the molten metal during the welding process.

Is it the stress that, produces strain or strain produces stress?

A Force applied to an object will cause a displacement. Strain is effectively a measure of this displacement (change in length divided by original length).
Stress is the Force applied divided by the area it is applied.

Therefore, the applied force produces both Stress and Strain. Stress and Strain” are linked together by various material properties such as Poisson's ratio and Young's Modulus.

DMRC Assistant Manager Interview questions (Signal and Telecommunication)

Explain AM and FM.

AM-Amplitude modulation is a type of modulation where the amplitude of the carrier signal is varied in accordance with the information bearing signal.

 FM-Frequency modulation is a type of modulation where the frequency of the carrier signal is varied in accordance with the information bearing signal. 

Where do we use AM and FM?

AM is used for video signals for example TV. Ranges from 535 to 1705 kHz.

FM is used for audio signals for example Radio. Ranges from 88 to 108 MHz.

What is communication?

Communication means transferring a signal from the transmitter which passes through a medium or say channel then the output is received at the receiver.

Different types of communications? Explain.

Analog is the process of taking an audio or video signal (the human voice) and translating it into electronic pulses.

Digital on the other hand is breaking the signal into a binary format where the audio or video data is represented by a series of "1"s and "0"s.

State Sampling Theorem.

It states that, while taking the samples of a continuous signal, it has to be taken care that the sampling rate is equal to or greater than twice the cut off frequency and the minimum sampling rate is known as the Nyquist rate.

What is Instrumentation Amplifier (IA) and what are all the advantages?

An instrumentation amplifier is a differential op-amp circuit providing high input impedances with ease of gain adjustment by varying a single resistor.

What is modulation? And where it is utilized?

Modulation is the process of varying some characteristic of a periodic wave with external signals. Modulation is utilized to send an information bearing signal over long distances.

What is the need for load flow study?

The load flow study of a power system is essential to decide the best operation existing system and for planning the future expansion of the system. It is also essential for designing the power system.

What is demodulation?

Demodulation is the act of removing the modulation from an analog signal to get the original baseband signal back. Demodulating is necessary because the receiver system receives a modulated signal with specific characteristics and it needs to turn it to base-band.

What is a base station?

Base station is a radio receiver/transmitter that serves as the hub of the local wireless network, and may also be the gateway between a wired network and the wireless network.

What is a repeater?

A repeater is an electronic device that receives a signal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances without degradation.

What is crosstalk?

Crosstalk is a form of interference caused by signals in nearby conductors. The most common example is hearing an unwanted conversation on the telephone. Crosstalk can also occur in radios, televisions, networking equipment, and even electric guitars.

What is Barkhausen criteria?

Barkhausen criteria, without which you will not know which conditions, are to be satisfied for oscillations. Oscillations will not be sustained if, at the oscillator frequency, the magnitude of the product of the transfer gain of the amplifier and the magnitude of the feedback factor of the feedback network are less than unity.

Advantages of negative feedback over positive feedback

Negative feedback processes lead systems towards equilibrium states. Positive feedback reinforces a given tendency of a system and can lead a system away from equilibrium states, possibly causing quite unexpected results.


Code division multiple access (CDMA) is a channel access method utilized by various radio communication technologies. CDMA employs spread-spectrum technology and a special coding scheme to allow multiple users to be multiplexed over the same physical channel. Time division multiple access (TDMA) divides access by time, while frequency-division multiple access (FDMA) divides it by frequency.

DMRC Assistant Manager Interview Questions (CIVIL)

Civil engineering deals with the design, construction and maintenance of buildings, roads, bridges, artificial waterways, dams etc. Interview questions for civil engineers include strength of materials, material science, energy engineering, environmental engineering and earthquake engineering.

What is diversion tunnel in a dam?

When a dam is to be built, a diversion tunnel is usually bored through solid rock next to the dam site to bypass the dam construction site. The dam is built while the river flows through the diversion tunnel.

 What is green building?

Green building is a holistic concept that starts with the understanding that the built environment can have profound effects, both positive and negative, on the natural environment, as well as the people who inhabit buildings every day. Green building is an effort to amplify the positive and mitigate the negative of these effects throughout the entire life cycle of a building.

How do you measure concrete?

Cubic feet, Cubic yards, Cubic Meter

What is a positive displacement pump?

A positive displacement pump causes a liquid or gas to move by trapping a fixed amount of fluid or gas and then forcing that trapped volume into the discharge pipe. Positive displacement pumps can be further classified as either rotary-type or lobe pumps similar to oil pumps used in car engines. These pumps give a non-pulsating output or displacement unlike the reciprocating pumps. Hence, they are called positive displacement pumps.

Why does the pressure increase under soil?

Soil pressure increases with depth due to the overburden or self-weight of the soil and due to loads imposed upon the soil.

For example, the pressure variation below the depth of soil is linear and the relation is given by pressure = unit wt * depth. As depth increases, there will be a linear increase in the soil pressure.

What is aggregate?

Aggregate is the component of a composite material used to resist compressive stress.                                                           

 Define Modulus of Elasticity?

 Modulus of Elasticity, also known as elastic modulus is the elastic deformation tendency of a material. In the stress strain curve the slope is the elastic modulus.

What are the causes of building collapse?

The Passage of time is one reason. Buildings also collapse due to weak foundations. Earthquakes, hurricanes and other natural disasters can also damage the structure of the buildings and cause it to collapse. Bombings or demolition of buildings is also other reasons.

What is the chemical composition of cement?

 Cement primarily consists of CaO. The chemical composition of Portland cement is tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite.

How do you calculate the power of a centrifugal pump?

The input power, that is, the power required to operate the pump should be stated in Hp (horsepower) on the pump's nameplate. It can also be calculated by the 3-phase power equation:

P(in Hp) = VI(1.7c) = Rated Voltage x Rated Current x 1.73/ %Efficiency

What is tensile strength?

It is the maximum longitudinal stress that an object can withstand without necking. It denotes the maximum point in a stress strain curve.

Explain soil analysis.

Soil testing is a qualitative analysis to determine the nutritional and elemental composition of soil. Soil is mostly tested for elements such as nitrogen, phosphorus and potassium. It is also tested for acidity, moisture, organic contents and contaminants.

What do you mean by honeycomb in concrete?

Some people call it an air pocket in the concrete or a void. It is the exposed course aggregates on surface of concrete without covered by mortar or surrounding the aggregate particles.

What are the points in the stress strain curve for mild steel?

The points in the stress strain curve for mild steel are Proportional limit, elastic limit or yield point, ultimate stress and stress at failure.

What are building codes?

Building codes are a set of specifications regarding minimum safety conditions that any building should take in account during construction. Building codes deal with the height, spacing, installations of a building.

What is fire resistance rating?

It is a measure of time up to which a system could resist the fire resistance test. It is generally depicted by a time-temperature graph.

What is the Richter scale?

The Richter scale, a base 10 logarithmic scale, is a measure to quantify the seismic energy from an earthquake.

 What is the quantity of 20mm concrete, sand used for 1 cum R.C.C?

 The total volume of materials needed for getting 1cum of concrete is 1.5cum.

 The mix prop for M20 is 1:1.5:3.

 So let a be the qty of cement,then




 so cement=0.27cum,sand=o.41cum,gravel=0.81cum.

What are the applications of modulus of elasticity?

As the term implies, "Modulus of Elasticity” relates to the elasticity or "flexibility" of a material. The value of modulus of elasticity is very much significant relating to deflection of certain materials used in the construction industry.

Take for example the general E value of mild carbon steel is about 200 GPA compared to about 70 GPA for aluminum. This simply translate that aluminum is 3 times flexible than steel.

What is the purpose of the gap in the road on this bridge?

Purpose of the gap in the road is to allow the road to expand and contract with temperature changes without causing damage or deformation to the road.

What is a projection line?

Projection line is the way, in which the earth is shown on a flat piece of Paper.

DMRC Assistant Manager Interview Questions (General)

Here are few general questions that are asked during the interview:

Tell me about yourself.

This is the first question the candidate will be asked in any interview. This may sound simple but if you are unprepared it will create a big problem. So just prepare yourself for this simple yet difficult question. Start with one two lines about yourself, who you are? A brief 1 line about your family .Tell about your achievements but never sound too proud of your achievements.


 “”First Impression is the last impression”.”

 What are your strengths?

This question is to judge how you present yourself, are you the person who talks too much, are you arrogant or are you the one who just do what others say and thus never realized your strengths.

Some points on which you could support your answer could be honesty, leadership, confident, good communication skills, positive attitude etc.

What are your greatest weaknesses?

This question which could either end your interview or could just get you the job. Don’t mince with words, at the same time just don’t be too blunt. Tell your weakness but also tell what you are doing to overcome it.

What are your hobbies?

This question is asked to judge your personality.

Mention some hobbies which are directly or indirectly linked with the job. But make sure you have that hobby. If not then say what you actually do.                        

DMRC Interview: General Preparation Tips

"You never get a second chance to make a first impression", and that's actually quite true—which is why it's so important to start on the right foot.

Everyone's different, there are few things you'll want to keep in mind that should help show you in a positive light while preparing for a job or employment interview.

Small things make a huge difference and here are few tips to make the first impression the best and make the interview a successful one.

  • Your interview starts the moment you walk into the building; anyone you meet may be connected with the hiring team.
  • Be nice to everyone you meet from the receptionist up to the senior-level executives.
  • If there are several people for interview at the same time, give everyone equal attention; you never know who the real decision maker is.
  • Answer interview questions by communicating strong stories of success; prove what makes you “unique” rather than just explaining what you did.
  • Try to ask questions throughout the interview.
  • Asking questions during the interview helps you uncover key issues and better prepares you to answer questions throughout the interview.
  • When asked questions about mistakes you have made, be authentic, explain what you learned from that particular experience, and don't get defensive.
  • If asked about your weaknesses, don't spin weaknesses into strengths.
  • Be confident and answer the questions they ask without nervousness and with proper eye contact.
  • Be a good listener. The questions asked provide clues to what the hiring manager needs and expects.
  • Be memorable for what you say during an interview, not for what you wear.
  • Try to relax - don’t sit on the edge of your chair and don't lean too far back: sit up straight and still.

DMRC Assistant Manager Group Discussion

Group Discussion is a process where the exchange of ideas and opinions are debated upon. This process is mostly used for selecting the candidates for admission in various fields. This the round before the interview for the final selection in the DMRC Exam.

The most important group discussion tips that you should keep in mind while participating in GD and know how to handle group discussions!

  • Always carry a pen and a notebook.
  • Make Sure you Read Widely
  • Choose Magazines that are Rich in Content
  • Work on your Communication Skills
  • Be yourself and do not be arrogant.
  • Be Confident and maintain eye contact with team members.
  • Listen to the Topic Given During GD Carefully
  • Try and Maintain a Balance in your Tone
  • Listening to the Skills carefully, this is the most important part as this can help you to respond to the other persons.
  • Be positive and do not be over confident.
  • Be the first and also the Last to Speak

Here are few latest topics that are mainly discussed in the Group Discussion round of the Exam:

  • How is Technology impacting the Banking sector?
  • The validity of science lies in its power to predict
  • Nuclear power good for increasing power demands
  • Mobile phones - requirement of the day
  • Futuristic Internet connected glasses - A technology overdose?
  • Technology Creates Income Disparities
  • Technology: The Ism' Of The New Millennium?
  • Science Is A Boon Or Bane

Good Luck!

*The article might have information for the previous academic years, please refer the official website of the exam.