1.BARC INTERVIEW DATE – 24.5.2018
I entered and stood behind chair.
Sir -sit down please.
Me-Thank you Sir.
(4sir+1mam) all were smiling.
1-Where do you belong?
2-Asked about AMU entrance test. (Because of my college- AMU)
3-You came alone?
4- Mumbai kab pohonche?
5- So you got enough sleep?
6-Gave me a page and pencil and asked me to write 5 core mechanical subjects.
(SOM, THERMODYNAMICS, HT, VIBRATION, ENGG. MECHANICS)
Q1- Told me to draw a conical horizontal bar and specified temperature at both ends and asked me to draw temp profile.
Q2- Same as above but thermal conductivity varying with temperature.
Q3 -Told me to draw a cylinder and specified temperature at outer area and somewhere in middle and asked me to tell the temp profile.
Q4- Same as above but thermal conductivity varying with temperature.
Q5- Same as above but now gave K1, K2. And asked me to show the variation again.
Q6- Draw a bar and apply axial forces P on 1 cross section, 2P on other cross section.
Will there be any stress?
What will this remaining P do to this bar?
What about velocity and acceleration of this bar.
If the bar is dropped from a height?
What happens to velocity and acceleration?
Q7- Draw a cantilever beam and apply a vertical load at some gap from free end asked me to draw deflection curve.
I answered but he gave me some alternate curves and asked me that ” aisa bhi to ho skta hai..Apne waisa hi kyu banaya “?
Q7- Asked what type of stress bar will feel.
Q8- Then told me to assume the cross-section of bar to be solid circular and asked me to draw bending stress variation.
Q9- Now assume it hollow circular and asked bending stress variation.
Q10- Now made it thinner (more hollow) and asked the difference.
Q11- What is section modulus?
Q12- Effect of section modulus in above question.
Q13- What is failure?
Q14- Cycle ko turn karte time velocity kyu kam karte hai aur tilt kyu karte hai ?
Q15- Draw a vertical ring with a bead at bottom (it can slide over the ring) and rotated it about vertical axis and asked where this bead will stay?
Q16- A tank filled with water supported over a support at middle. If disturbed it can topple on any side. Put a thread in water along the breadth of tank dividing the tank in two parts
Now put wooden small balls on one side of thread one by one without jerk thread will restrict them from going on other side
What will happen will it topple?
Q17- Boiling will be fast where? At plane or at the top of hill? Why?
Q18- Heat a vessel with water inside and cool it under tap suddenly now when you open it, it does not open easily why??
Q19- Draw a metallic cylinder with a piston in equilibrium initially inside condition (P1, V1). Now restrict the motion of piston and put a weight W over it. Now remove the restrictions .What will happen? Draw the process.
Q20- Same as above but now put weight gradually in fraction of W/100. Till it reaches, what will happen? Asked me to differentiate between both conditions.
Interview finished.
Then asked me about when I will return?
Where I am staying? Have I got admission in IIT? Did you liked your today’s interview? Is it your first interview? Then permitted me to leave…
My interview was last interview of that day.
Duration: 1 hour.
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2. BARC INTERVIEW DATE – 7.6.2018
AIR – 16
VENUE – MUMBAI
INTERVIEW DURATION: 1:15 HOURS
5 minutes general talks to make environment comfortable.
Q1. Write your favourite subjects.
Q2. A diagram of cantilever is given with inclined load and asked to draw its SFD, BMD.
Q3. Find critical cross-section in the given cantilever.
Q4. Derive formula for deflection at free end.
Q5. Show variation in SFD and BMD if load is shifted towards fixed end.
Q6. Show stress distribution of composite beam.
Q7. Draw Mohr’s circle for critical cross-section in cantilever and explain it.
Q8. Piston cylinder arrangement was given with electric heater in it and asked to draw P-V diagram.
Q9. A cylinder of air (150 bar and 50 degree celcius) plus other data and asked to find heat supplied till the pressure drop to 10 bar as the cylinder valve is opened.
Q10. Air conditioner work on which principle?
Draw the cycle and T-s diagram.
Explain function of each component.
Q11. Which factor decides working pressure of condenser?
Q12. How to increase COP of VCRS?
Q13. Why condenser of refrigerator is inside room?
Q14. A furnace of composite cylindrical walls was given and asked to draw temperature profiles.
Q15. Drive expression for temperature profile in terms of distance from one end in a conical solid tube having different temperatures at its ends.
Q16. What are the controlling factors to decide height of pump from sump level..
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3. BARC INTERVIEW DATE – 03 November, 2021.
Token no 1, Panel no 5.
Duration: 1hr 25 minutes
Interview result: Selected for OCES-MECHANICAL at BARC Mumbai
I went in at 10.30.
There were 6 members on the panel. They sit in a round fashion and candidates have a chair at the centre. A whiteboard behind the candidate for the interview. They asked some basic questions like My Graduation College and my family background.
I will refer to the chairman and other Members of panel as C, M1, and M2 respectively.
Chairman: so do you know how the interviews at BARC go? Did you ask any seniors?
Me: I searched on the internet. I will be asked about my favourite subjects and then asked questions from those subjects.
M1: yes, we do that because we want to see how you perform in subjects that you are comfortable in.
C: now go and write your subjects on the whiteboard in the top right corner.
Me: (writes Basic thermodynamics, SOM, FM, and HT.
C: is this the order in which you prefer them to be asked?
Me: Yes. (They didn’t follow the order though. SOM was asked at the very last)
C: Have you heard of properties? What are they?
Me: Properties are certain characteristics of system that we use to define the state of the system.
C: can you tell the type of properties?
Me: Yes, we have intensive properties and extensive properties. Intensive properties are those whose value does not depend on the mass. And extensive properties are those that depend on mass of the system.
C: can you give some examples?
Me: yes we can consider the air in this room and the air in a water bottle open to room initially and then capped. The mass of air in the room and in the bottle will be different, but the temperature will be the same, so temperature is an intensive property.
C: and extensive?
Me: we can consider the volume of the bottle and room, since they are different and depend of mass of the air, volume is an extensive property.
C: and what about Cp and Cv? You heard about that?
Me: Yes, Cp is the specific heat at constant pressure and Cv is specific heat at constant Volume.
C: Explain in detail what they mean.
Me: Cv is the amount of heat needed to increase the temperature of gas of one kg by 1 Degrees C at constant volume. And Cp is the amount of heat needed to raise the temperature of gas of 1 kg mass by 1 Degrees C at constant pressure.
C: Say I have one kg of unknown gas in a piston cylinder arrangement. Draw it. Now tell how you will measure Cp and Cv.
Me: ok. (Think for a few seconds to get my thoughts together). Is the piston massless or does it have some mass?
C: ……
Me: Well it makes no difference either way.
C: Exactly.
Me: We can attach a stopper on the other side of piston to restrict its motion. (Draws it). Then we can supply a known amount of heat to the gas and measure the corresponding temperature rise. Due to the stopper the piston will not move and process will be constant volume. We can now use Q = m Cv (T2-T1). m = 1 kg. And for Cp we will repeat the same process without stopper and it will occur at constant pressure.
M1: and what are your assumptions for this process?
Me: Both Cp and Cv vary with temperature but this variation is very small over a small temperature range. So I assumed it to be constant and the value that we will get is average value.
M1: that is correct, but that’s not what I’m asking….
M2: Do you remember the Bomb Calorimeter? You must have studied it in school.
Me: Yes, We use it to measure the calorific value of certain substances. It has surrounding water and when we burn the substance, the corresponding temperature rise and apply energy balance to find out the calorific value.
M2: so what assumptions do I make? (He was actually giving me hint for previous question asked by M1 about the assumptions)
C: say that in the specific heat measurement question, you have the cylinder made of copper. Now tell your assumptions. (This was a straight forward hint and I immediately caught it)
Me: Yes, some of the heat that we supply will also go to the cylinder. To compensate for that, we will also measure the temperature rise of the cylinder. Then we can find out the portion of total heat absorbed by the cylinder and then we can subtract that from the total heat to find out the actual heat supplied to gas and now use this value to calculate Cp and Cv.
M3: How many specific heats can a given gas have? (This was easy only if you know your basics).
Me: well, from any given initial state a gas can perform an infinite number of different types of processes, and for each process we can calculate the specific heat. So we can have an infinite number of specific heats. Out of all these, Cp and Cv often occur in our analysis and it greatly simplifies the analysis if we know these values. So we treat them as special and keep a note of them.
M3: Good.
C: now consider a piston cylinder with a gas and it is heated, show this process on PV diagram.
Me: (draws it correctly as a horizontal line from left to right)
C: now we want to cool it, we can do that slowly or rapidly, show them again on PV diagram.
Me: Well, for slow cooling, the same line that I previously drew would be traced back.
C: and for fast?
(I tried a lot but couldn’t answer this one. there was a lot of back and forth. We later move to next question.)
M3: (here comes a series of tricky questions). A gas follows a process PV^3 = constant. It is heated from state 1 to 2. Calculate the heat supplied.
Me: (I was solving it while speaking, but it was a vague question and would have taken some time. So M3 interrupted and formulated another similar question with more concrete data)
M3: We have one mole of N2 gas having 1 cu. m volume and 300 K. it undergoes a process V = kT^2. The final temp is 500K. Now calculate the heat supplied.
Me: (writes all given data.
Q = (delta U) +W.
Delta U = n Cv (500–300) …… (Cv is molar Cv)
Use gas law PV/T = constant. Then substitute the given process to find relationship between P and V.
Now W = integral (PdV). Substitute the relationship and perform the integral)
M3: Ok this is enough. (This wraps up thermodynamics and we move on to next subject FM)
M3: (hands out a paper with syphon diagram and asks to draw it. Diagram in pdf) calculate the exit velocity. Neglect all losses.
Me: directly applies formula and tells answer.
C: How did you get this formula?
Me: applies Bernoulli’s theorem and derives it.
M3: ok now we change the 4m height at make it 12 m. now calculate the exit velocity
Me: Uses same formula and tells answer. (it was actually wrong. The flow will not occur due to vapour formation, we concluded that later, proceed to next question.)
M2: Two tanks having areas 2A and A are connected at bottom by a closed pipe. Tank one is filled up to height H and tank two is empty. Now the pipe is opened, what will happen? (Diagram in pdf)
Me: Flow will occur from tank 1 to 2 until their levels become equal.
C: What will be the final height?
Me: (Starts solving)
C: Tell from intuition (smiles).
Me: (starts thinking)
M2: ok consider that both tanks have equal areas and draw the height vs time graph. For both tanks on same graph.
Me: (I draw it as a curve from H reaching H/2 with decreasing slope and for other tank 0 to H/2 with decreasing slope.)
C: Answer my previous question. If areas are 2A and A, tell the final height.
Me: Sir chota sa calculation karta hu na..
C: (smiles) ok karo karo.
Me: (solves. it was a two line calculation. Final height 2H/3).
M3: (Here comes a tricky question, I think it was the trickiest one I was asked) Draw two tanks of area A and connected by a pipe at bottom, both filled up to height H. 2nd tank has a tap connected to its bottom. Now plot the height vs time graph for both tanks. When tap is opened.
Me: (wrote mass balance equation for 2nd tank. drew its graph. Then wrote mass balance equation for 1st tank, drew it. It will take a lot of time to write these equations here so I will skip it.)
C: suppose you have a tank connected to a dam and it has a tap on the other side. The tap was initially closed and the water in tank has height H and it is in level with dam (diagram in pdf). What will happen if we open the tap?
Me: at the instant the tap is opened, the water jet will flow out at V = root (2gH). This will lower the tank height, but the dam is a big reservoir and its level will be unaffected. As the flow proceeds, there is a difference in height of dam and tank as delta h. So water will flow from dam to tank with V = root (2g delta h). Now as flow proceeds the tank exit flow rate will reduce from a max value to lower and the inlet flow rate will increase from zero to some higher value. When these two values become equal, equilibrium is established and that height will be final height and remain unchanged later.
C: ok tell the final height.
Me: (apply mass balance. the final height is H/2).
M1: can you calculate the time?
Me: (again writing mass balance, but this time in differential form and for unsteady part of the flow. I don’t think that I would have been able to solve that DE, but as soon as I was done with formulating the equation, M1 said that’s enough. Moving on to Heat transfer)
M4: Consider a lake in Kashmir that has frozen. Ambient temperature is -15 degrees C at height 5 feet above the surface and the water below the frozen layer of ice is 4 degrees C. Draw the temperature variation with depth from that 5 feet above point to water below.
Me: (draws a straight vertical line from -15 point up to just above the ice surface, then boundary layer temperature profile below that going up to the surface where I showed temperature below 0 degrees C. (chairman sir said very good as I first drew the straight line instead of drawing a curve right from the start). Then in the ice section a straight inclined line reaching 0 degrees C at the bottom surface, the a boundary layer profile from 0 to 4 deg C
M4: What will be the direction of heat transfer?
Me: From water to ice.
M4: (tries to suggest something in the ice-water zone. I don’t get it. So gives an example). Do you know evaporation process? What is the direction of heat transfer? Where does the vapour get the required heat from?
Me: Yes I know, as the vapour evaporates it will absorb heat from the surrounding water body that it was previously a part of, leading to cooling of that water body.
M4: Yes. Now tell about this example.
Me: (still don’t get it. Move to next question)
M4: Consider a vertical rod. Draw it. Current is flowing through the rod. Draw its temperature profile from the centre to the ambient.
Me: (Draws a parabolic profile from max temp at centre reducing parabolic ally up to surface and then a boundary layer temp profile.)
M4: If I want to lower the temperature of centre, what can I do?
Me: we can insulate the rod and use the concepts of critical radius. (We had a lot of talk on critical radius topic)
M4: ok now consider that this rod has a thin drilled hole at its centre. Now draw the temperature profile
Me: (first I clear all the assumptions to avoid cross questions. then draw a parabolic profile from outer radius to the thin drilled whole radius)
M4: now what will be the max temp, will it be more or less? If it is less, can we not do this instead of insulating?
C: Draw both the profiles on each other.
Me: (thinks for quite a while. then about to say something)
M4: ok let it be.
C: you want to add anything, then say it.
Me: As we are drilling the hole, we are removing out the volume, so the heat generated per unit volume will also increase. So the max temp will be more in this case.
M2: (whispers to M4, as if they didn’t think of it while framing the question) Yes he is correct.
(Done with HT. now SOM)
M5: (hands over a piece of paper with a diagram of hook on it. refer pdf for diagram. After I draw it, questions start) which diameter is bigger, D or d?
Me: D
M5: Ok now suppose you have the value of d, can you calculate D?
Me: Yes (First I define permissible stresses. then calculate permissible load from tensile stress acting on d. Then use bending plus tension to calculate D. I was asked to draw stress profile while I was calculating. I did that)
M3: the cross section of hook is not circular in practice, what shape is it? Draw it
Me: (Draws a trapezium)
M3: Explain this shape
Me: The inner portion of hook is subjected to bending tension plus normal tension. So these stresses are going to add up and resultant stress
Will be very high, so we need more area there and we use the thick side of trapezium there. While on the outer portion bending compressive and direct tension act, which tend to cancel each other out and the resulting stress will be not very high, so we need less area (thin side of the trapezium)
M5: What is more elastic, steel or rubber.
Me: It depends on what parameters we consider for elasticity. If we consider Elastic Constant, then steel has a higher value. If we consider Elastic limit stress, again steel has a higher value. If we consider elastic strain then rubber has higher value. While designing we give more preference to strength, so we can conclude that steel is more elastic.
C: Draw the Stress vs. strain for steel and rubber
Me: (draws a steep line) If we draw it on true scale, we will see a vertical line.
C: Yes that’s correct, this is just the representation, or else we won’t be able to see the elastic strain at all. Now draw for rubber on same graph.
Me: (draws a straight line will less slope. while I was drawing Chairman sir interrupted and asked if it will be a straight line) It will be straight line up to the proportional limit, then past that limit even though the line will not be straight but the rubber will still be elastic for some more deformation up to the elastic limit.
C: ok. You can leave now…
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4. BARC INTERVIEW DATE – 31/05/2017
VENUE: MUMBAI
Reached the interview place at 8.30 A.M. (reporting time). After check-in, gone to BARC training school building. There they gathered all the people in one hall (very well organized, as expected from a reputed organization). There they did the document verification and all. Gave students number according to which they will be appearing for the interview.
It will be a long answer so be patient…
Now coming to the interview…
My number was 9 and there were 4 rooms where simultaneously interview was taken.
Total 5-panel members were there. So they started with some casual questions,
Member 1: So your name ********* right?
Me: Yes sir.
Member 2: Please be seated (as I was standing beside the chair).
Me: Thank you, sir.
Member 1: So you graduated in 2016?
Me: Yes, sir
Member 1: Ok, so what were you doing one year?
Me: I was preparing for the Gate sir.
Member 2: Ok, Have you given the BARC’s test?
Me: No sir.
Member 1: From which college you have done your graduation?
Me: Told the college name, Nasik (Maharashtra)
Member 1: and 12th?
Me: Told the college name, Nasik
Member 1: Ok, So you belong to Nasik
Me: Yes sir.
Now the Technical part
Member 1: Let’s move to technical part Sachin
Me: Ok sir.
Told them the subject as I wrote on the paper simultaneously. (My subject was Thermodynamics, Strength of materials, fluid mechanics and heat transfer)
They asked any other subject you want to add?
I said no sir.
Member 1: Tell me what you learned about the thermodynamics?
Me: Told about the laws, cycles and all
While I was giving answers to the member 1 other started preparing and writing down the question from the subjects I told.
Member 1: Ok. Tell me about zeroth law
Me: gave the answer.
Same goes up to the 3rd law.
Me: Sir I don’t remember the 3rd law.
Member 4: (trying to help me) kiske bareme hey wo kuchh yad aa raha hey?
Me: Sir I don’t remember the statement but it’s about the Absolute zero temperature.
Member 1: Ok, tell me the name of different cycles.
Me: Told Carnot and Rankine cycle.
Member 1: tell me the cycles exists in nature or I make them?
Me: (I was not sure of the answer) Sir we make it
Member 1: where we use the carnot cycle?
Me: Sir we don’t use it in a practical situation as it is an ideal cycle.
Member 1: So what is the use of it?
Me: It is used for comparison.
Member 2: Ok, now can you tell us where we use the Rankine cycle.
Me: Sir Steam power plant.
Member 2: Passing the paper told me to draw the T-S diagram of the Rankine cycle.
I started drawing. (As I did not read any of the Technical after the gate and it’s been like 3 months so all the cycle and all were mixed)
Drawn the cycle without the vapor dome.
Member 2: Are you sure about the diagram? Tell me about the processes
Me: Yes sir, told about it correctly.
Member 2: (now he wanted to give me a hint in his own way) draw the component diagram of this
Drawn all the parts like boiler, pump, turbine, and condenser. Sir asked me about the different phases at a different point, told them with confidence.
Member 2: tell me the temperature will increase linearly in boiler?
Me: No sir there will phase change and at that time the temp will remain constant.
Member 2: so can you show me the same thing in T-S diagram.
Then I realised what blunder I made. I asked there said sorry and corrected the diagram. I was having a smile on my face. So silly mistake I have done here.
Member 2: Now tell me if we have two steam power plant one in shimla and one in Mumbai then which one will give more network output?
Me: After thinking for 2 min told them it will be shimla.
Member 2: Why?
Me: Because the environmental conditions. The pressure and temp at the outlet will be low that’s why the pressure difference increases and hence the work output.
Member 2: but it will also increase the pump work.
Me: Stopped for a sec. But sir as water is having higher density so the work required will not change as much as the work generated by the turbine.
Member 2 looked satisfied with my answer.
Then He passed me the paper on which he wrote down the question.
It was like there are two steel containers, both containing the same gas. One with condition P, 4V and T other with 2P, 2V and T. The atm condition are P atm and T. Both the containers are connected with pipe and a valve. If we open the valve what will happen?
I told them the gas will flow from higher to lower pressure and then equilibrium will be there.
Member 2: Calculate the final pressure.
After some mistakes and hints given I did get the solution
Now it was time for next question. Member 3 passed me his sheet. The question was about the cantilever beam with point load at the end. And two arrangements of rectangular cross section where there.
Member 3: which one of this arrangement will you use in the design?
Me: the one with more height.
Member 3: write down the stress formula amd tell me the stress distribution
Told him.
Member 3: draw SFD and BMD.
Then he increased the difficulty by saying that now the beam is having its weight now what will be the diagrams?
He told me to superimpose them on the previous one.
Answered it.
Next question was from FM asked by member 4.
Member 4: There are two steel plates one is horizontal and one is vertical. Which one will float on water and which will not?
There was a tank full of water drawn on paper and two sheets with dimensions.
Me: Depending upon the buoyancy force.
Then asked me about how the ship floats over the water. Told him.
Then he said there is a weightless balloon inside the water tank containing the same water. What will happen to it?
Me: sir it will remain in equilibrium.
Member 4: If I push it downwards then?
Me: If there is no drag it will be moving continuously.
Then he asked some more questions.
After that Member 5 starts with my final subject HT. In the question, there were two surfaces connected with a bolt and he told me to draw the temperature variations.
I did that.
This was my experience with the BARC Interview.
Thank you for reading and being patient. As it happened 3-4 days ago I remember it clearly so I shared the details so that it will help you.
My interview lasted for an hour or so. It was the best interview I ever had. The results are not declared yet. I will update as soon as the results are out ;).
All the best for your interview.
RESULT: – The results are out and I am not selected for BARC (expected). As I did some terrible mistake due to lack of preparation ;).
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5. BARC INTERVIEW
AIR-244
VENUE: MUMBAI
The panel consisted of 4 members.
They began with a brief 10-15 minutes discussion about my home place and reasons why I left my previous job and also asked what I know about BARC Interviews.
They were very friendly and easy going and told me to be calm and stress free.
After that they asked me to write down my favourite subjects.
I wrote:
1) SOM
2) Thermodynamics
3) Heat Transfer
4) Fluid Mechanics
Q-1: A container containing 10 kg of water is kept on weighing scale .If a string is tied to a 1 kg ball (density 10 times than water) and is immersed in the container, how the reading of weighing scale will change?? (From the time when ball is completely outside the water to the point when it is completely submerged; assuming tank is sufficiently large so that water does not overflows out of tank).
Q-2 A gas is contained in a frictionless cylinder-piston arrangement whose walls are sufficiently long and the surface above piston is exposed to atmospheric pressure. The whole assembly is turned upside down suddenly (so that pistons starts moving down due to its weight). They asked me to draw P-V diagram of the whole process till a steady state is reached.
Q-3.A balloon is being inflated with air isothermally so that both pressure and volume of air inside balloon is increasing. Then why PV=RT is not followed in this case?? (LHS is increasing while RHS remains same)They also asked me one more question on fluid which they linked with the design afterwards (although I didn’t wrote design in my favourite subjects).
They kept on providing hints in the whole interview which lasted for one hour.
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6. BARC INTERVIEW EXPERIENCE
DATE OF INTERVIEW: 28/12/2020
BRANCH: MECHANICAL ENGINEERING
INTERVIEW VENUE: ANUSHAKTINAGAR, BARC MUMBAI
INTERVIEW TIME: 10:25AM TO 11:40AM (1hr 15mins)
INTERVIEW RESULT: SELECTED AS OCES TRAINEE
I was selected based on my Gate score which was 844 and the cut-off for an interview was 840. After document verification, I was the first candidate from the mechanical branch to be interviewed on that day in the 2nd Panel. After document verification, they give a slip for an interview.
In the Panel, there was a total of 8 members including chairmen.
Me: May I come in Sir? (Initially, I did not go with my document file).
Chairmen (CH): Where is your document file? Go and bring that file.
Me: (I rushed back and get the file to them).
CH: Please sit here. Where are you from?
Me: From Aurangabad, Maharashtra.
CH: Where did you complete your B.Tech? And when did you passed out?
Me: Sir from College Of Engineering Pune, and I graduated in 2018.
CH: What you did in the last 2 years?
Me: Sir, after my graduation, I worked in MNC for half a year and then left the job for the preparation of GATE and research organization examination like ISRO, DRDO, and BARC.
CH: Then did you interviewed in this organization?
Me: ISRO declared their result but the interview is not done yet and DRDO has not been shortlisted till now because of the pandemic so this is my first interview.
CH: Do you know how this BARC interview goes?
Me: Yes Sir, some of my senior works here, so they told me about all of this.
CH: Okay go on the board and write down 4-5 favourite subjects.
Me: Writing Basic Thermodynamics, one of the members interrupted and said to write in short. Then
I wrote HT, FM, SOM and MD.
CH: (Starting with thermodynamics) Draw Pot having water, having a constant heat supply draw a temperature versus time graph.
Me: I had drawn a diagram and temperature versus time graph. (But it was an open beaker and I had initially drawn a steam line also in the graph)
M2: Now draw mass versus time graph.
Me: I was drawing a diagram so I got my mistake that steam will not remain in the open beaker so it will not heat up.
M2: Do mass will become zero after all water gets vaporized?
Me: Yes mass will become zero.
CH: Explain this linear graph? Why this is linear? (As I have drawn linearly decreasing graph in phase change process)
Me: (Thinking) So I was trying to give an answer mathematically but he interrupted and said try to answer by physics. (I was confused)
M2: Think about this graph, is it remain linear?
Me: Because of continuous evaporation and leaking out from the top, so I was confused and thought it will not remain linear so I promptly said parabolic ally decreasing.
CH: Now explain this curve now.
Me: This time I was stuck and unable to answer properly. But at last, I said linear only by saying q”*t=mL after trying to get slope by derivative it was coming linear but member 2 interrupted and said in-phase change process mass is varying continuously so how can you take the derivative of that. After some cross-question, I gave up.
CH: Okay rough the board and draw a sphere of radius R having high temperature then put it into the ambient. Draw temperature versus time graph.
Me: Initially deriving equations mathematically, so he interrupted me and said draw with intuition and basic physics. (As I was knowing the curve but trying to answer in a detailed manner but this time they were in hurry). So I have drawn an exponentially decreasing curve.
CH: Explain this curve.
Me: Explained.
CH: Now take the sphere of radius 2R and superimpose the curve on the same graph.
Me: Answered.
CH: Give a comparison between both curves.
Me: Answered.
CH: Now take a cube of the same mass as a sphere with radius R now what changes will happen with the curve?
Me: Trying to answer it by the thermal time constant, so he interrupted and said is it necessary to do that. So I get the hint and said that no sir, as the surface area of a cube is high so it will cool faster than a sphere. Answered the graph also.
CH: Draw temperature profile from the centreline of the sphere to outer ambient environment.
Me: I have drawn parabolically decreasing inside the sphere and in outside according to natural convection.
CH: Explain the graph?
Me: Trying to explain but he interrupted and said for this analysis we take some conditions. So got a hint, and said yes sir we assumed it as a lumped system while Biot Number is less than 0.1.
CH: Explain Biot number?
Me: Answered.
CH: Now correct the graph inside the sphere.
Me: Made correction. (As conduction resistance is negligible it will somehow remain flat)
(Now they changed subject to FM)
M3: (passing paper) Draw this diagram on board and give pressure at each point and calculate height.
Me: Drawn the diagram and calculated pressures at each point.
M3: Is pressure will remain the same at points D and E.
Me: (Confused for some moment) finally answered. Again cross-questions happened and he was trying to get it in some direction then Chairmen stopped him and asking to rough the manometer and draw only the tank having a small opening at the bottom and sidewall.
CH: Now assume these two openings are acting independently on two different tanks then which tank gets drain faster.
Me: Answered.
CH: Now both tanks are at some height h now tell me which tank fluid will hit first at the ground.
Me: Explained all the things.
CH: Consider tank having height H filled with fluid. Now as the pressure at the bottom is high and at the surface pressure is low then can fluid flow from bottom to top.
Me: No sir, it will depend on energy.
CH: Connect pipe from bottom to top, now can fluid flow from this pipe from bottom to up?
Me: Strongly answering as “No”. (Some cross-questions happened and somehow I tried to answer it. Now they wrapped up FM and started with SOM)
M4: Draw a cantilever with a point load at some distance from the end.
Me: Drawn.
M4: Now draw deflection curve, SFD, BMD.
Me: Here while drawing BMD I have mistakenly drawn BMD in positive.
M4: Is BMD correct?
Me: After thinking for some moment I corrected it.
M4: Is the slope of points B and C is same?
Me: Yes Sir.
M4: Now draw UDL from point B to C.
Me: Drawn.
M4: Now superimpose all the diagrams in the above SFD, BMD diagram.
Me: Drawn. Here I was doing a mistake in SFD.
M4: Is SFD is correct?
Me: (Thinking for the moment) drawn again but incorrect.
M4: Take P+W load on point B and clear the UDL now draw SFD.
Me: This is time I made the correct diagram.
M4: Now do it same in the above case with UDL.
Me: Drawn correctly.
M4: Now look at the deflection curve, is it correct?
Me: (Because of superimposition of curves I was getting confused, so initially I made mistake but after some time made it correctly) drawn correct diagram.
M4: Take a square cross-section of beam and diamond cross-section of beam, now tell me which one is better for bending stress.
Me: (Because of exhaustion) I said diamond because its y is greater than square c/s.
M4: Think carefully.
Me: I wrote bending formula and they said it will depend on I/y.
M4: Calculate for both c/s and tell me which one is better.
Me: This time they allowed me to derive I of the diamond as I forgot that. After some derivation I come to conclusion that square will be best than diamond and said I/y values correctly.
M5: Draw bending stress distribution in square cross-section.
Me: Drawn.
M5: Now cut the beam horizontally along the length now superimpose the stress distribution in the above diagram.
Me: (I didn’t ask is that glued or free promptly assumed glued and drawn)
M5: Explain the stress distribution.
Me: While answering they said both are free at the cutting surface, now this time I made corrections and drawn.
CH: Now cut the beam vertically along the length and draw stress distribution.
Me: Somehow drawn as changes in I.
M5: Explain that distribution.
Me: Explained.
M6: Now make the same beam hollow and superimpose the same stress distribution.
Me: (Till now that diagram gets very messy) I asked shall I draw a new diagram.
M5: Take colour chalks but draw on that same only.
Me: Somehow in the confused state, I have drawn.
CH: Explain it and compare it with all other situations?
Me: Answered.
(Now they switched subject)
M7: Take vertical self-weight beam, tell me whether this beam has any limit for its length?
Me: Answered according to deflection and yield point.
M7: Where it will fail?
Me: At the fixed-top support
M7: Consider support is rigid?
Me: Sir it fails just below of fixed support.
M7: Ok.
(M7 was trying to ask something but chairmen interrupted and stopped him. He gave me the slip and my document file)
Me: Said thank you to all.
Results were declared on 5th January in the evening. A total of 48 students were selected from mechanical out of 690 who appeared for interviews. Finally I was selected for NFC Hyderabad Training School as TSO.
This was my overall experience at BARC interview. Only final note I want to give that don’t hope that your interview will go in your way only. Prepare according to your time and at the time of interview just feel relax. Because of pressure situation I made many mistakes during interview, but at the same time I recovered it as well. So be calm and give the interview.
Thank you and wishing you all the very best.
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7. BARC OCES/DGFS 2019 INTERVIEW EXPERIENCE:
Date: 12/06/2019 (Last day for interviews)
Slot: 8:30 AM
I went to Mumbai a day prior to the interview and got the stay at Hostel inside Anushaktinagar.
The next day morning I went to the office where interviews will be conducted by 8:15 AM. They allowed all the reported candidates inside a hall after 8:30 AM for document verification and few other applications to fill (viz. Travel allowance, Personal details etc…). After document verification, we will get a slip with a serial number on it. Then we have to go for the biometric verification after which snacks will be provided and then we have to wait in the waiting hall till they call our serial number for interview. The waiting time depends on your serial number. I went inside waiting hall by 11:15 AM and got my call after the lunch at 2:30 PM (my serial no. : 21).
Inside the interview room 5 members (I1 – I5) are sitting around a table. (Its a 6 member panel, chairman of the panel came after 20 minutes of the interview).
Me: May I come in sir.
I1: Come in. Sit down
Me: Thank you sir
I1: Give me your file
Firstly some general questions like when you came? Where you stayed? Is the stay comfortable? Etc…
I1: So you are doing your M.Tech from NIT Trichy?
Me: Yes sir
I1: Write your favourite subjects on this paper
Me: Basic TD, SOM, FM, HT.
I1 Sighs to other panel member
I2: See. These are 2 piston cylinder arrangements with side walls insulated. Both are having same initial conditions (P1 V1 T1). In one cylinder O2 gas and other cylinder CO2 gas is present. Same amount of heat (q) is supplied. Now which piston cylinder produces more work?
After thinking for some time
Me: Masses of the gases will be different
I2: ok
Me: It is a constant pressure process sir
I2: ok. Draw PV diagram for this process
Me: Drawn a horizontal line
Me: As it is a constant pressure process which will have more expansion, it will give more PDV work
I2: Which will have more expansion
Me: PV=mRT and R= 8.314/M and M is more for CO2. So V will be less. So O2 will do more work
I2: Really?
After thinking for some more time
Me: Q= mCdT. So which gas has more heat capacity it will have less increase in temperature and also volume? So it will give less more and the other will do more work
I2: Which gas has more heat capacity?
Me: c=g/(g-1). So c depends on gamma (g). O2 is diatomic and have g = 1.4 and CO2 is triatomic and has g = 1.33
I2: Who told you cp= g/(g-1)
Me: Proved with meyers equation.
Me: Again tried to do something with Q= mCdT but got struck
I2: Ok let’s keep it aside for now. Sighs other member and says one round of TD is over.
I3 shows a paper with HT question of pipe
I3: Its a pipe with fluid flowing with intial conditions (p = 1 atm, m, T= 50 C) and last portion is insulated.Temp at end is 150C. Draw Temp. With Length profile
After thinking for some time
Me: Draw linearly increasing line from 50 to 100, then constant, then again linear till 150C.
I3: Why you drawn horizontal at 100C
Me: Sir water changes phase at 100C
I3: Water changes phase only at 100C? What are you assuming?
Me: Pressure is atmospheric
I3: Right. Did we say that?
Me: atmospheric pressure is 1.012 bar which is nearly 1 bar. So I assumed it
I3: What if it is gauge pressure
Me: Then the phase change takes place at higher temperatures
I3: What if it is absolute pressure
Me: If I have to consider exactly. Then 1 is slightly less than 1.012 so boiling takes place a little temp. Below 100
I3: Like 98
Me: Like 99 point some thing
I3: How do you think pressure is constant inside pipe? I will be varying. Right?
Me: Yes sir, it will be decreasing
I3: Why
Me: Because of friction
I3: Right. If we assume a decrease of 0.2 bar. How will the graph change?
After thinking for some time
Me: It will boil at a lower temperature and drawn a line joining 50C with a lower temperature
I3: Two lines with different slopes?
Me: No sir. Same line with previous slope but till a temp. Below 100C
I1: What will be wall temperature with length profile?
Not able to answer
I3: Why heat will flow
Me: Because of temperature difference
I2: Don’t give hints. I will cut his marks still didnt get it
I2: What is the equation for heat transfer in wall?
I still didn’t get anything
I3: What are the modes of heat transfer?
Me: conduction, convection and radiation (Then it clicked in my mind)
Me: Through the cylinder heat gets conducted and then gets convected into the water.
Me: The variation of the temp will be logarithmic through the cylinder
I3: Till now you said that temp. Will be linear and now you changed?
Me: Along the length area is constant. But through the cylinder the area is continuously varying
I3: What graph we asked
Me: wall temp vs length
I3: Draw that
Me: Temp flows from wall to fluid. It means that wall has a higher temperature than the fluid
I3: Thats what we are trying to hint you from before.
Me: Then drawn a linear line with higher temp. Than fluid temperature
I1: What is laminar and turbulent flow?
Me: explained
I1: How will be the velocity profile for both flows?
Me: Drawn parabolic and logarithmic
I1: At the centre which flow will have more velocity
Thinking
I4: What is reynolds number and how you differentiate laminar from turbulent
Me: said
I4: As reynolds number has velocity in numerator and turbulent flow has high Re. It will have more velocity
Me: Accepted
I4: Shown the FM question. Initially tank is vacant. Both the inlet and outlet openings have same diameter and m mass flow rate enters the tank. After some time will there be any water in the tank or not. If yes what is the height of water level
After thinking for some time
Me: No water will be there
Chairman: Have a cool head and think one more time
Me: Water level will rise till the height such that outlet velocity equals to the inlet velocity
I4: Draw height vs time graph
Me: Drawn
I5: Now we will test your strength. Do you have strength?
Me: yes
I5: What is stress and strength?
Me: explained
I5: Shown the SOM question. The pendulum is oscillating. Design the beam
Me: Tried to design beam by considering weight of pendulum as point load at the end of beam
Me: The force can be transferred to the vertical member by creating a force and a couple
I5: But the pendulum is oscillating. Don’t you think the distance increases when it moves away. We have to design for the maximum condition
Me: Considered the maximum distance and designed
I5: Stress variation, critical section, Neutral axis
I5: Questioned about orientation of rectangular cross section and flitched beam concept
Me: Answered
I1: Your time is over. Good. Happy journey
Me: Thank you sir.
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8. BARC INTERVIEW – MECHANICAL ENGG.
VENUE: MUMBAI
Entered the room with a wish.
Talk about whether have you taken coaching or not?
Purely Technical.
Also asked to bring my certificates folder because to have a look at courses.
- Draw PV diagram for all process and also its usage in different cycles.
- If you heat a container for long time then draw temperature profile.
- Elongation in a bar due to its own weight. Derive..
- Efficiency of power plant and where these losses are maximum. (Ans: In condenser the losses will be maximum)
- Based on above question, why we are using condenser. They wanted to ask me why not just put the water after turbine to pump?
- Draw the stress strain diagram. What is factor of safety? Why it’s used?
Suggestion: have a look at derivation of different formulas.
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9. BARC INTERVIEW – 2016.
Venue: Mumbai
The interview at BARC only tests basic knowledge of mechanical engineering. However, it is considered as the toughest technical interview of the country.
You will initially give a sheet of paper and a pencil. You’ll be asked to write down 4–5 subjects of your choice. Questions asked will test the fundamental concepts of the subject. Interviewers are very helpful as well as friendly. They keep on encouraging you to find the right answer if you get stuck at any point of time.
You have to be thorough with all concepts of the subjects that you choose. Even though questions will be asked from only those, the interviewers make sure that you have an in-depth knowledge about it. The usual duration of a BARC interview is around 45–60 minutes and as the duration increases after this threshold, your chances of getting selected also increases.
Subjects of my choice were Strength of Materials, Heat Transfer, Fluid Mechanics and Vibrations. The questions asked in my interview were
- What’s stress and strain? Give the tensor form of Generalised Hooke’s Law.
- You’re given a long bar with a force P at one end 3P at the other. What’s the stress in the bar? Is there any stress due to inertial forces?
- Plot the variation of heat flux and temperature across the wall of a plane wall and a hollow cylinder, if outside temperature is higher than inside temperature. Explain why.
- What’s the physical significance of Prandtl number?
- What do you think about shear stress acting on hydrophobic surfaces? Will it be zero?
My interview lasted for an hour and 10 minutes. It was a different experience all together. And one any person serious about research must attend..
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10. BARC INTERVIEW – 2017
DATE OF INTERVIEW: 9/6/2017
TIME: 5:40 PM TO 7:00 PM
BRANCH: MECHANICAL ENGINEERING
RESULT: SELECTED AS OCES TRAINEE
My interview was last interview of the day by panel given to me (there were 6 panel for Mechanical engineering and I got 3rd panel)
Me: may I come in?
Member 1: yes please sit down
They were in hurry, I didn’t even get chance to wish them good evening (honestly they don’t care either)
M1: (member of interview panel =M from now on) so are you staying at hostel of BARC?
Me: yes sir.
M1: did you properly have lunch?
Me: yes sir.
I wasn’t looking nervous or worried so they didn’t waste much time in introduction and all (they don’t care about that either, if you are terrified then they might spend 10min to calm you down)
They gave me a pencil and an A-4 size page.
M1: ok, Ashish now we want you to write 4-5 subjects you are most comfortable in.
Me: (writing and speaking at the same time as each of the five members were noting down these subjects in a piece of paper of their own) 1.Strength of material
M1: you can use short forms
Me: 2) FM
3) HT
4) MD
Basic Thermodynamics
M1 gave M2 signal to start.
M2: ok, there’s a bar with load of 3P acting on one of its side, what will be the stress?
Me: there will be no stress if we neglect all frictions. Body will accelerate with a=3P/m
M2: we add a force of 5P on other side. Now what will there be stress?
Me: (after thinking for few seconds) body will have a stress of 3P/A and acceleration of 2P/m
M2: will the stress be uniform longitudinally or will it vary?
Me: Sir this is a case of dynamic analysis, in btech we have studied till static stress analysis so if I have to go based on that then it will be uniform longitudinally but it might be possible that it varies from maximum at 5P side and minimum at 3P side.
M1: but will there be stress at all?
Me: yes sir stress will be present.
M1: ok Ashish, if I drop a ball from certain height will there be stress when it freely falls?
Me: are we considering air drag?
M1:No.
Me: Then there will be no stress.
M1: then how is this bar stressed?
Me: sir, if we consider that same ball falling freely and tie it with an elastic band on top and then let it fall then it is both falling and resisting against the band, in this case there will be stress in the ball since it is resisting aginst something.
M1: ok(indicating M3 to ask his question)
M3: (draws a tank with one hole at bottom face, one at outlet of vertical pipe attached at bottom face and last also at bottom but on vertical face) what are velocities at each of these outlets?
Me 🙁 using Bernoulli’s equation derived velocities)
M1: now buckets under each stream at same level, which one will fill first?
Me: first one.
M1: why?
Me: highest velocity
M2: which one will fill second?
Me: other 2 will fill simultaneously…. Ok wait… Stream from third hole is having a projectile type stream
I started using equations of projectile motion.. Filled almost a page…
M1: Is this necessary?
M3: what are you trying to do?
Me: sir, I am trying to find the velocity of stream just before it gets into bucket as that would give us volume flow rate and as we know volume of bucket we can find time taken to fill it.
M1: ok continue.
Me: further using projectile motion equations in x and y axis.
M4: (after 4-5 seconds) sometimes analysis is not necessary. Use your engineering sense, which one do you think will fill faster.
M2: yes use method of feeling.
Me: (after few seconds, trying to feel) I think second hole will fill first.
M1: sure?
Me: (thinking)
M1: do you think in third whole water has to travel larger distance?
Me: yes sir, I get it.
M1: Is this the only reason for 2nd stream filling bucket before 3rd one?
Me: yes sir.
M1: ok, indicating 5th member to ask question.
M5: have you done tensile test?
Me: sir, I’ve not done it because our college didn’t had the apparatus, but I’ve seen videos on it.
M5: What does the specimen look like?
Me: (drew the shape) the length to diameter ratio is 10:1, lines are marked on specimen at equal interval.
M5: how do we measure stain?
Me: we use stain gauge.
M5: how is it placed?
Me: showed it in drawing
M5: why are lines marked?
Me: after some time elongation becomes large enough, we don’t need stain gauge anymore and we can measure it directly using these lines.
M5: draw stress station curve.
Me: for?
M1: Mild steel
Me: drawing and explaining at the same time.
M5: explain various points.
Me: (explained)
They did not get into dislocation theory and luder’s band.
M2: see Ashish, fracture point has lower stress than what we had even before upper yield point so why doesn’t it fall there itself?
Me: (thinking for 3-5 seconds) sir the stress what we are showing here is the force divided by original area, actually after ultimate stress point necking will take place and actual stress will increase.
M4: what is that stress called?
Me: true stress.
M4 🙁 has a smile on his face) and what is this stress called? The one you have shown on y axis?
Me: Engineering stress.
M3: Now draw the diagram for aluminium.
Me: (drawn)
M1: Where’s the yield point?
Me: specific yield point is not visible in stress strain curve of aluminium.
M3: how do we know it for engineering purposes?
Me: (even though I knew the answer I knew this is a bit high level question that most Mechanical engineering students are not aware of, so I pretended to think and recall and answered in 2-5 seconds) sir there’s something called proof stress.
M1: what is it?
Me:sir we draw a line with slope equal to modules of elasticity and having intersection at x axis at 0.02% strain. Wherever this line intersect the curve is our yield point.
M1: Good.
Tip: see there are two ways of impressing interviewers, either give all the answers you know instantly in which they will keep on raising difficulty level and ultimately you will reach a point where whatever you have studied is covered and now they will ask questions in portion you have not studied and you are forced to think and use your imagination. Or play in area you are comfortable in, just pretend to be uncomfortable, show that you are thinking and the answers are not recorded in your head. Because how far you can think beyond what you have studied is all they want to see. For you 1st law of thermodynamics might be easy and entropy might be difficult, for them everything is easy like A, B, C, D… to you. They just want to see if you are able to think beyond what you’ve studied. Obviously they also check whether you know your basic subjects well but that part everyone is good at, that is necessary condition but not sufficient. Now I’m not saying that do this pretending thing at every question because then they will see right through it. But whenever you get a chance add it. But for doing this you have to remain calm. BARC was the only interview I had as my GATE 2017 rank was 1825 and I had already dropped an year after btech so pressure was high but I learned to control it. I knew if I have to make it happen tension and worry will not help me and that a calm and composed mind can do anything it wants to.
M4: two vertical bars, one with area A and another with area 2A,same material ,fixed at top to a rigid support and at bottom to a rigid bar which remains parallel to horizontal as we apply Force in vertical direction. Which bar will fail first?
Me: (using compatibility equation to find force in both members)
M4: what are you trying to do?
Me: sir, I’m trying to find out stress in each of the bars the i’ll divide it with area to find stress, which ever will have higher stress will fail first.
M4: ok, continue.
Me: (found out that F2=2F1) sir, stresses will be same (I was little surprised myself)
M1: but how is that possible? Area of cross sections are different.
Me: Sir, forces will be different but area of cross sections are also different so stresses are same. We can see if in another way too, as lower rigid bar remains parallel, strain in both bars are same and since material is both members are same modules of elasticity are same thus stresses will be same in both.
M1: there is a pipe with uniform heat flux throughout its length, water is passing through it, inlet temperature is 25C outlet temperature is 160C, pressure is 1atm..Draw the temperature profile of water?
Me: (drew a straight line with positive slope from inlet to outlet)
M1: are you sure?
Me: (thinking for few seconds) ok sir there’s a mistake.
M1: use the eraser.
Me:(drawing again, drew a curve-positive slope-decreasing slips) sir as the water passes is temperature will rise so heat flux will decrease thus rate of heat transfer will decrease…..
M1: heat flux is constant.
Me: ok, that slipped my mind, then slope will also be constant i.e. We will get a straight line… (Thinking for few seconds..)
M1: see, water is entering,what do you think is leaving ?
Me: ok, it will become stream till it reaches outlet.
M1: draw the curve.
Me: (drew straight line, positive slope then at 100C 0 slope till some distance then again positive slope till 160C)
M1: which portion will have maximum length?
Me: q.x=mc(dT) and q.x= m(LH). If mass flow rate is m, heat flux per unit length is q an x is unknown for each of the tgree portions. We can find x factor r each portion.
M1: use the values and find out which lenghth is largest.
Me: c of water in s 4.18kj/kgK latent heat of evaporation is 2300 Kj/kgK and Cp of steam( trying to recall for few seconds) sir, I dont remember.
M1: ok, compare the first two.
Me: x is proportional to c and LH. So second portion will be much longer than first portion.
M1: what is triple point?
Me: it is the point at which all three phases, solid, liquid and gases exist in equilibrium.
M1: what is critical point temperature for water?
Me: 273.16C
M1: are you talking about critical point?
Me: oh sorry sir, did you ask critical point?
M1: yes, what is it?
Me: ok, critical point is something completely different than triple point, it is the point at or beyond which liquid will directly convert to gaseous phase without consuming any latent heat.
M1: ok what is critical point pressure and temperature for water?
Me: (trying to recal for 2-3 seconds) sir I cannot remember.
M1: Ok (indicating M4 to ask next question)
M4: (drew a structure with conical part on left and attached to it a cylindrical part, like a nail, left side temp. Is 400k, left side it is 300k) draw the temperature profile.
Me: (drew curve with increasing slope in left portion and straight line on right portion.
M1: draw the curve outside too. Surrounding’s temperature is 300 and 400 not the surface temp.
Me: ok sir then there will be formation of thermal boundary layer.
M2: draw it.
Me: (drew it) sir natural connection will be taking place.
M2: No no draw the temperature profile.
Me: (drew it, decreasing slope outside)
M2: what do you think will be the thickness of this thermal boundary layer?
Me: it will be small, we can actually feel it if we are physically present near the surface.
M2: how thick? Is it in mm or cm or m?
Me: few cms sir.
M1: if in this structure(nail one),we drill a hole throughout how will the curve change.
Me: it will be like this only.
M1: no no, there will be some chabges.
Me: sir, the hole is if constant cross section so in left part area is area will change but it is still similar function of x as before.
M2: you are not listening what he is getting to say, listen carefully (by now more than 75 minutes had passed and my energy was completely drained out since I already waited for 6 hours before interview, and on top of that I was the only one, the interviewers didn’t offer anything to eat or drink for all the time I was in interview room)
M1: See Ashish, the graph will be similar but do you think slope will change?
Me: Yes sir, slopes will definitely change.
M1: will or increase or decrease?
Me: sir, q=kA(dt/dx)
M1: what is that law called?
Me: ( thinking for 5-6 seconds, I was confused between Fourier’s law and Newton’s law of cooling, taking your time to give correct answer in one shot is always better than speaking quickly and being wrong) Fourier’s law.
M1: so, increase our decrease?
Me: slope is inversely related to area of cross section. As in drilling hole, area decreases so slope will increase.
M1: Ok Ashish you can go now.
Me: Thank you sir(going out )
M4: please leave the pencil.
Me: (with a smile) sorry sir.
M4: Thank you Ashish, all the best.
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11. BARC INTERVIEW – 2019
VENUE: HBNI MUMBAI.
DATE OF INTERVIEW: 30 MAY
TOKEN NO: 14.
INTERVIEW DURATION: 50-52 MINS.
BRANCH: MECHANICAL ENGINEERING
I reached the training hostel one day prior to the interview.
General declaimer to the students who are going to attend the interview for the first time, don’t take Mumbai local in the rush hour which is 8 AM to 10 AM instead prefer cab or auto. After reaching BARC I went to the training hostel and booked a room till next morning 8:30 AM, they are very strict about the timing. I had to report to the venue on 8:30 AM. After reaching to the BARC interview venue the documents verification took place. It took around half and hour and then they’ll provide you a green slip on which the serial number is written. Then I had to go to a room where they’ll biometric check the finger prints and take photographs. After that they gave me a little refreshment containing some snacks and a frooti pack. Then I went to the waiting hall where one by one students were being called for the interview. My turn came at exactly 12:00 PM they made me wait for 5 min before the interview room and then a bell rang and real show began.
There were 6 members. I greeted each of them and then they asked me to sit down and started calling me down.
I1: So ******* kaise ho aap? ( So ******,where are you from?)
Me: Sir basically from Bihar but currently living in Delhi.
I1: okay so what are you doing in Delhi?
Me: Told about my job profile.
I2: What is difference in Mumbai and Delhi climate wise?
Me: Sir, I find Delhi more comfortable because of the less humidity but here in Mumbai the temperature is not much but the humidity makes it intolerable.
13: Where are you staying? You had breakfast how was it? Is there any suggestion you want to give us for improvement?
Me: No sir everything is perfect.( Even though I wanted to say a lot of things :-p).
I1: Okay so let’s start with the interview, write down your favourite subjects.
Me: SOM, HT, BT, FM.
I1: (He had drawn a circular prismatic bar on which a torque was applied on the free end ,he gave the values of radius, modulus of rigidity and length and he had also drawn something on the right side of paper but the hid that with his hand and said that only focus on the initial figure and calculate the angle of twist on the free end).
Me: I used the formula and started calculating the angle of twist then he said to take the value of pie as 3 for approximation. Finally I calculated the value as 0.002 radian.
I1: Correct! Now listen carefully what we want is to reduce this value to 50% of its initial value and for that we are using a protruded bar from the free end which will strike at a pin preventing it from freely twisting. Now how would you design the pin?
Me: It took me 5 minutes to understand the situation then I started solving and finally was able to solve and design it correctly.
12: ( He drew two copper and steel plate kept together. The length and cross sectional area of both was same. It was open to the environment on one side and on one side a constant heat flux was incident on it and asked me to draw the temperature profile of both along the length.) This was the case of two fins kept together and it was not as simple as it looks but still I took some time and as I was about to draw something on the paper he said choro ye jyada complicated ho gya( leave it it became more complicated) and then he insulated the lateral surface of the bars and asked me to draw the temperature profile. I did some mistake in profile and they started to roast me why you’ve drawn the profile like this. Finally the discussion went for 10 Min and I gave in.
I3: Drew a tank in which water was filled up to height H and he said if I am pushing a plastic ball with my finger to the bottom of the tank and exactly at the bottom most point I removed my finger then draw the velocity versus height graph and velocity versus time graph. I draw one graph correct and there was some mistake in other one and finally the discussion went for 15 min.
Finally the experience was awesome the panel was very calm and chill and even giving me some hints whenever I used to stuck on some point.
Thank you.
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12. BARC INTERVIEW – GENERAL POINTS.
First of all, you can’t prepare yourself for BARC Mechanical Engineering interview in one month. It’s not like you will mug up some formulas or some definition or certain concepts just one month before the interview.
These are some points you may find worth following,
- The interview is purely technical, they will generally will ask you to write down 5 subjects that you claim you are good at and will start with your your choice.
- They will start with very basic questions e.g. what’s the boiling point of water? How does it vary with pressure? Etc. Gradually they they take you up to the next level. And yes! Why and how will be asked after every question.
- They don’t ask you to do some long complicated derivation, but yes small logical formulation may be asked e.g. how do you get the formula for Principle Stresses?
- They ask questions related to temporal as well as spatial variation of some parameter in a physical problem e.g. how the stress will vary with length of a slender round bar when it is subjected to two unequal similar forces (say P and 2P) at the ends?
- They expect you to think critically when you are being interviewed. They may ask, what will happen if a particular parameter is changed or what if a certain process is reversed kind of question. e.g. how the heat transfer rate will vary with radius if you put insulation from inside instead of outside in a steam carrying pipe?
- it’s very likely that they will drop you hints whenever you get stuck. Happened with me and many others.
Please note this is my personal experience during the interview and some discussion with my friends who faced the same. But in general the experience is similar only.