ISRO INTERVIEW EXPERIENCES

1.SRO INTERVIEW – 2018

DATE OF INTERVIEW: 22.2.2018

VENUE: DOS STAFF HOUSING, NEW DELHI

RESULT: SELECTED WITH A RANK OF 12

 

For written test:

• The time was major constrain for me and so for many others. You have to solve 80 questions in 90 minutes in which few of our numerical type without using calculator.
• Syllabus of the test is similar to that of GATE or ESE but I have observed few questions which are just new for me. The weightage of the subjects isn’t uniform. As I appeared in two tests of ISRO and have seen previous years question papers, there are always 4–5 questions on a particular topic from a particular subject. So I recommend you (aspirants) all to cover each and every topic in detail.
• Keep your calculations fast and if you think that question will take more time than average. Skip and mark it for the end.
• Have a deep knowledge of basic technical subjects of mechanical engineering.
• Take calculative risk. The penalty for the wrong answer is -1/3 of the marks assigned to that particular subject. If you don’t have a clue about the question, skip that but if you are stuck between two options, I suggest you all to take the risk and mark the most convincing.
• Make yourself comfortable in exam before the start by reaching 30 mins earlier than scheduled time.

Interview:

Well, It was morning of 22nd feb and I already reached Delhi with a friend of mine on 21st feb. I wore a formal trouser, shirt, shoe and tie.

I am graduate from SVNIT Surat in mechanical Engineering and currently working as an assistant manager in a bearing manufacturing industry. I had two research intern, one at IITG and another at IISc Bangalore.

I asked to report at 11.00 AM and so did I, 30 min before the reporting time. The document verification started around 3.00 PM and the members at document verification were very frank and supportive (Even they provided a bed if someone want to rest), but they too got exhausted till 9.00 PM. My turn came around 8.30 PM.

The panel consist of 10 people including chairman. The interview was purely technical. It went for about 30–40 minutes.

*Me enters the hall*

Me: Good evening everyone!

Chairman: Good evening Chun Raam! (mumbling my name as it is difficult to pronounce and asking the recruiting officer that Is he last or anyone else is left?)

RO: Yes sir! He is the last.

Chairman: So tell me about yourself.

Me: I told him little about my background, my education, projects in the college, competitions I had participated, current employment and research intern.

*I highlighted my research intern.

Chairman: So what you did at IIT Guwahati under manas das.

Me: Explained him about my project at IITG, neural networks, genetic algorithm, and need for optimization and modelling in mechanical processes and systems.

Chairman: What are favourite subjects?

Me: Sir I am afraid that I have to repeat the subjects which are you hearing from morning like fluid dynamics, heat transfer, SOM but apart from that I have keen interest in optimization and computational heat transfer and fluid dynamics.

*Chairman signed to another panel member who was expert of fluid I think*

I1: What is irrotational flow?

Me: Sir I will explain u theoretical and then mathematically.

Chairman: Don’t divert the interview. Keep it brief and to the point.

Me: Okay sorry sir! back to question, If a fluid element in fluid flow moves forward without rotation then flow is irrotational and mathematically if the curl of velocity field is zero then the flow is irrotational.

I1: So if I have viscous fluid and a less viscous fluid. Which has more chances of being irrotational.

Me: Viscous fluid have more chances and flow will laminar except for boundary layer.

I1: Why not in boundary layer?

Me: There is a gradient of velocity in Y direction.

I1: What is deciding factor for the flow?

Me: Reynolds number.

I1: What is stream line?

Me: Explained.

I1: What is path line?

Me: Explained.

I1: So which one is Eulerian approach and which one is Lagrangian approach?

Me: Explained.

I1: What is the condition for the highest point in siphon?

Me: Sir, the pressure at that point should be more than vapour pressure of the fluid.

I1: What is the maximum height of siphon in the case of water?

Me: its about 6 meters.

I1: what is stream function?

Me: explained.

I1: What is velocity potential function?

Me: explained.

I1: What is the angle between them?

Me: sir they are orthogonal.

*he asked around 25 question like rapid fire round*

I2: Enough from fluid, lets come to strength of material.

Me: Okay sir!

I2: If I give u material and I have to calculate the young’s modulus of elasticity. How will u do it?

Me: I explained that I will use Universal testing machine for the same and plot the stress and strain and calculate the required.

I2: How will u calculate the strain?

Me: Strain gauge.

I2: Where will u put strain gauge?

Me: At the specified and pre decided length of the specimen.

I2: Explain it further.

Me: Sir let’s say we have a specimen of length L and we have decided to that we will keep the two ends of strain gauge at x length symmetrical to the centre.

I2: You can use white board if u want.

Me: Okay sure sir! Thank you.

I drew a cylinder and marked its length as L and made two points and drew strain gauge.

I2: Have u done the experimentation in your college.

Me: Yes sir.

I2: Then are u sure that specimen looks like this.

Me: Then I remembered that the diameter of specimen at the end is large and then centre. So I drew something like this.

I2: Why the diameter at ends is higher?

Me: May be for better gripping. * Confused.

*Later I came to know that it is to have a uniform stress at desired specimen.

I3: You sure or not sure.

Me: Not sure sir.

I2: Okay leave. How will you calculate shear modulus using this?

Me: Sir for that I have to calculate Poisson’s ratio first.

I2: So what’s Poisson’s ratio.

Me: its ratio of lateral strain to longitudinal strain.

I2: How will u calculate it?

Me: I will calculate the change in diameter and calculate the…..

I2 interrupted: Is it really necessary to calculate the change in diameter?

Me: We can do it by keeping the volume constant but it will not stand true for every material.

I2: Okay good. What’s the relation?

Me On board: E=3K(1–2u)

I2: What’s K over here?

Me: I am sorry sir. That’s bulk modulus of elasticity and I corrected it as E=2G(1+u).

I4: So you told that you are interested in computational heat transfer.

Me: Yes sir. I have done few projects by solving governing equations numerically using C as programming language and have little exposure of software ANSI and fluent.

I4: So what are modes of heat transfer?

Me: Sir basically there are three modes of heat transfer. Conduction, convection and radiation. There is another one, free molecular conduction which is also part of conduction so yaa three.

I4: What are type of convection?

Me: Sir natural and forced.

I4: Explain them.

Me: Explained.

I4: So I will give you case study, There is tall building and heat is being transferred from its top.

*I drew the building on board and applied a sign for heat in.

I4: There is a cold air at the bottom and for natural circulation, What should be the height of building.

Me: I told him that the characteristic length in the Grashof number will be the height of the building.

I4: Do you have any idea about Rayleigh number?

Me: Yes sir. It is product of Grashof and Prandlt number.

I4: So what will be the deciding value of Rayleigh number for natural circulation?

Me: Sir I am not sure about the exact numerical value but it will be in the range of 10^9.

I5: What you did at IISc bangalore?

*I had a project on high temperature superconducting motor helium coupling design and heat load calculation in centre for cryogenics technology, IISc bangalore.

Me: Explained him.

I4: So you got exposure of computational fluid dynamics and heat transfer from here.

Me: yes sir and along with that I had an elective course work during my under graduation.

Chairman: Do you have any education gap?

Me: No sir.

Chairman: What are doing after graduation? I think you did your graduation in 2016. (Looking into my bio data form)

Me: Sir, I am currently working as an assistant manager in a bearing manufacturing industry.

Chairman: In which department?

Me: Sir Production.

Chairman: Where in Production?

Me: Sir on grinding lines.

*They started staring at each other.

Chairman: So thank you so much Chuna Ram (This time he pronounced it right ;)) and one last question “Why do you want to join ISRO?”

Me: Sir I was always in research and that’s what I wanted to do. It would be a pleasure to do the things of my interest in an esteemed organization like ISRO and for my country.

Chairman: Okay, Thank you.

Me: Thank you so much sir.

*and I walked out of room and handed over the TA form to recruiting officer and ran for metro. :p

TIPS FOR THE ASPIRANTS:

• Do not try to fool the panel, they are holding an experience of twice of our age.
• Keep your fundamental clear and try to be logical.
• Be confident and wear formal attire.
• Prepare your project, intern, current employment and recent & future projects of ISRO.
• Do not hide your employment or intern. (As I have seen few people hiding their intern and employment as they were afraid that panel is going to ask questions about it, but I would suggest you to prepare for it instead of hiding)

Result: I got 72.80 marks in interview and got selected with a rank of 12.

 

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2. ISRO INTERVIEW – 2016

DATE OF INTERVIEW: 13.12.2016

VENUE: NRSC, Hyderabad

I was asked to report at 8 a.m. morning and my interview begin at around 12 noon. It went for about 25 min and panel members were throwing questions. There were 7 members in panels including one at center (probably director) and 5 out of 7 asked me question and 2 did’nt. The interview was not that much stressful and also not that much supportive.

I entered the room and wished Good morning to all the members.

Director: You are passed out in 2016 from B.C.E.T Gurdaspur.

Me: Yes sir

Director: where is this college?

Me: Punjab, Near Pathankot.

Director: Is it a government college or private college?

Me: Govt. college…. Punjab Govt.

Director: What are you doing then after graduating?

Me: Pursuing M.Tech from IIT Bombay.

Director: Which stream?

Me: Aerospace Propulsion.

Director: Okay we will ask you about your B.Tech first and then come to your M.Tech later.

Me: Okay sir.

Director: So you have done two projects in your B.tech.

Me: one project I did as an academic project at my college and other I did at DRDL, Hyderabad when I was a Trainee there.

Director: First tell me about your Project at DRDL.

ME: This project ‘Experimental simulation of flame holding in air-breathing engines’ was particularly to simulate the combustion within the air-breathing engines particularly ramjets and to study about various kind of flames around us, there mechanism of formation, lifting criteria, blow off, flash back. Further CFD analysis was done so as to compare with the experimental results for the simulation.

Director: So you did CFD analysis.

Me: yes sir

Director: This project is computational or experimental.

Me: Both

Director: ok, then which solver you used for the CFD analysis.

Me: Fluent

Director: How you did it. Please explain on board.

I the draw the complete domain and the I draw the flame holder and told him about cavity and mesh generation and the told him about the Boundary conditions at inlet and exit and the told him about the materials used.

Director: you did it assuming laminar or turbulent flow?

Me: laminar flow using k-e model.

Director: How?

Me: Sorry sir, Turbulent flow using k-e model.

Director: You should tell this clearly. Is this reacting or non-reacting flow?

Me: Non-reacting. Simple air is considered.

Flow past the flame holder.

Director: Now draw the velocity profile after the v-gutter and above the mean line.

I was trying but I was unable to draw and I told him about the velocity-vector in the re-circulation zone.

Director : That is ok but you have not drawn the velocity profile yet.

Me: That I don’t know.

Director: Okay then.

Another panel member started to ask me the question.

Member 1 : what was your other project?

Me: Paddy Grains threshing machine.

Then I draw the complete mechanism on the board.

Member 2 : Did it worked?

Me: Yes we fabricated it.

Member 2: What were the design parameters?

Me: I designed it considering the bending strength of the shaft.

Member 2 gave me a case that if certain amount of force is applied to the pedal then how much will reach to thresh the paddy. I gave him the complete explanation that how to do it and was satisfied with my answer.

Member 3 : If I consider the pedal as a beam can you draw the FBD.

I tried it assuming the beam but when I fixed the both ends, he said it is wrong.

Member 3: How can you assume both the end of pedal to be fixed. Its wrong.

Member 4: What do you know about air-breathing engines?

Me: Those engines which takes the air from atmosphere for combustion are air-breathing engines.

Member 4: ISRO did some recent activity on air-breathing engines. Do you know?

Me: Yes sir, they tested a scramjet at speed of Mach 6.

Member 4: what is the difference between Ramjet and a scramjet engine?

Me: In Ramjet, the air is diffused to subsonic speed before entering the combustion chamber and then further expanded through nozzle while in scramjet the air remains supersonic throughout.

Member 4: Which fuel is used?

Me: Hydrocarbon fuel and Hydrogen fuel both can be used.

Member 4: Which is better? Hydrogen or Kerosene.

Me: Hydrogen, because it has more specific impulse.

Member 4: Why hydrogen has more specific impulse?

Me: Because the atomization and mixing in air stream is much faster for H2 rather than kerosene.

Director: The answer that is correct but since you are doing M.Tech we were expecting something more from you. You must have done a course on Propulsion in 1st semester.

Me: yes

Director: Then you should know.

Member 4: What is problem with hydrogen? Do you know?

Me: we need to liquefy it to store otherwise it will take huge volume.

Member 4: What is the temperature to liquefy hydrogen?

Me: That is something…….

Then Member 4 mummer something with director and they started laughing.

Member 4: Do you know how the combustion happens in the scramjet?

I started it by drawing the intake of scramjet and told them that there is an oblique shock due to which the flow turns by some amount without being slowed down. Member 4 pointed out the mistake that the tip or the cowl can be rounded in scramjet and started laughing. I corrected it.

Member 5: You have done some course on CNC Machines.

Me: Yes what sir?

Member 5: Have you done that course or not or someone else has done?

Me: Yes Sir.

Member 5: How many axes are there in the machine?

Me: There are machine with 4-axes, 5-axes, 6-axes.

Member 5: On which you worked how many were there?

Me: 4-axes

Member 5: Single point cutting tool moves in which direction? Horizontal or vertical.

I tried to explain all the axes by drawing on the board.

Member 5: No need to draw just give me verbal answer.

Me: X-direction

Member 5: ‘X’ okay.

Director: Okay now come to flame holder and if this is used in scramjet then what will happen.

Me: Since the flow in the scramjet will supersonic throughout thus there will be some detached oblique shocks ahead of v-gutter and characteristics of this oblique shock can be found out using theta-beta curve.

Director: Okay thankyou

I hope this will help you for your preparation.

 

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3. ISRO INTERVIEW – 2018

DATE OF INTERVIEW: 3.8.2018

VENUE: DELHI

RESULT: SELECTED – AIR-3

As I entered into the room, there was a panel of 10 members and Chairman. I wished them and they asked me to introduce yourself. But after 2–3 lines they stopped and started bombarding questions from various subjects as I was the last candidate that day, they got bored with the subjects like fluid mechanics, heat transfer, SOM. So they started with material science.

Panel member 1

1. What is the difference between grey cast iron and ductile cast iron?

Answer: Carbon is in free form in grey CI, so it is brittle and we add magnesium and cerium in CI to form ductile cast iron. The spheroids formed due to magnesium and cerium results into ductile behavior.

2. What is the diameter of spheroids you are talking about….i replied directly as sorry sir, I don’t know
3. What is stainless steel?

Answer: It is an iron based alloy having chromium and magnesium as major alloying elements.

4. Which element is responsible for corrosion resistance?

Answer: Chromium

5. Do you know about the phenomenon of chromium deposition?

Answer: This question is because they want me to tell how the addition of chromium leads to corrosion resistance,so I replied regarding the formation of chromium oxide which will be protecting the grain boundaries (region which is most susceptible of corrosion).

6. Types of stainless steel?

Answer: Martensitic, Austenitic and ferritic.

7. Can you please tell me which of the could undergo corrosion if I place them in water.

Answer: I asked panel some time to think, they had given me the same but after thinking for 1–2 minutes, I told them I don’t know.

8. Which of the stainless steel is non magnetic in nature.

Answer: Austenite stainless steel

9. Welding process for stainless steel

Answer: TIG and electron beam welding

10. Explain electron beam welding, TIG, MIG, submerged arc welding processes.

Answer: I answered.

11. Type of Electrode we use in MIG and TIG welding?

Answer: Consumable and bare electrode for MIG and non consumable for TIG.

Now comes panel member 2…..As I wrote about crack propagation project in bio data form, she asked me some questions regarding that.

1. Name some crack growth models….. Go to board.. Write the formula for all the laws.
2. Draw crack propagation stages graphs.
3. Modes of crack propagation.
4. What is stress intensity factor.
5. Relation of SIF with fracture toughness.
6. Difference between toughness and fracture toughness.
7. Which materials are more likely to undergo crack propagation.

Panel member 3: Do you know what is SHM. I used resisting force in definition… so they just said it is not resisting force….after sometime… I get that right.. It is restoring force.

1. Any mechanism in which we apply less force but we do large work.Design screw jack.
2. Design screw jack on board. This question stunned me the most but I again get back to my answer of “ I don’t know”
3. Pascal’s law and applications
4. Mechanism of hydraulic lift.
5. Destructive testing examples. I gave him some like UTM, izod charpy test.
6. What we measure from UTM test.
7. Explain izod and charpy test on board… difference between the two… and it measures what.
8. What do you think… indentation test is destructive or non destructive.
9. Formula used in brinells hardness test.
10. What is zeroth law. It’s application, temperature scales….i answered of 4 temperature scales.. Celsius, F, Kelvin, rankine.
11. Which is absolute scale. I replied of Kelvin but they corrected me and said that rankine scale is also absolute.Why Kelvin scale is absolute.

Finally my interview was over. Panel was sometimes sarcastic and sometimes cooperative.

I was shivering there while standing, so they called me to chair again and then they asked remaining questions from thermodynamics. But they laugh very often… don’t know why….. On the candidate foolish answers or they get impressed… it’s difficult to guess.

My interview was around 35–40 minutes. I left the room at 8: 35 PM and ran away from the building as I don’t want to face the interview panel members. I thought that my interview was not that good as they laugh at me a lot during interview. But after 20 days result came…….. I was in shock and also very very happy as my name appeared in the list on the third position (AIR 3).

For all candidates preparing for interview….please prepare at least 4 subjects. Questions are not that difficult but sometimes if you took more time in a particular question and not delivering it correctly will lead to loss of your interview time. They generally take 20–30 minutes of interview. So be honest… if u are not sure or u don’t know the answer….. Be genuine… directly say them.. You don’t know. This will allow them to ask other questions which u can answer. I personally answered 70 percent questions but still I was able to secure a good position. Don’t make wild guesses.

I you have some doubts regarding the above questions which I haven’t answered above….please let me know. I will surely try to fix it.

Thank you and all the best for your interviews.

 

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4. ISRO INTERVIEW – 2017

I have attended the interview yesterday.

I entered into the interview room and 9 members were sitting. I wished them and they wished me back. At first they asked me about my college. Then my B.E. project. I explained it in a systematic way as planned before.

(Dont go in without preparing your B.Tech / M.Tech Project thoroughly)

Then they asked how many theories of failure are there and explain it.

(My project is a mix of Design + FEA + HVAC + SOM)

Answered all 5 theories of failure with alias names and final design stress results.

They gave me a case for stress and asked how would I proceed further? Answered correctly ( critical fibre, principal stress application).

Then they asked What is the shear stress and bending moment distribution in hollow rectangular beam – Answered this one too.

(I prepared about it well in advance)

What is stiffness? I asked whether they are asking axial / bending stiffness, they asked me to tell the definition of stiffness and I explained, then they told me to explain about axial and bending stiffness ( as I asked them – lesson learnt – if i try to out smart them, it may end in vain), answered that one too correctly.

Then they asked me to draw a spring and told me to explain how diameter of coil varies with stiffness. I asked them permission to derive and explain. Initially they refused, then gave me a minute to derive. I competed it within a minute – found strain energy, apply castigliano theorem to find deflection, then stiffness. They asked how number of coils affects stiffness. Explained from the same formula.

The person sitting at centre (most probably – chairman) told me that ” you have answered all the questions from Structures. I am going to ask a question from heat transfer. Have you heard the name Bossinessq?”

I told them that i have heard of JJ Bossinessq hypothesis in turbulent flows, I said I have heard about it in turbulent flows fluid mechanics, may be he proposed his main theory in heat transfer, I am not sure. He seemed less satisfied and he said word “yes”. I was mentally unstable after impinged by continuous bombardment of questions on me. Then they said yes i had no idea what to do, closed marker pen and sat on the chair – (yes i am dumb!)

The chairperson with huge sarcasm, told me that I might leave and they want to conduct interview for some other people too. I apologized with a huge smile, greeted everyone and rushed out, while other panel members were laughing loud.

I felt that I had drawn the attention of every panel member, and 4-5 members asked me questions and I left no question unanswered.

I had interview in NRSC Hyderabad and panel members were very friendly and assisted me to answer whenever needed and I am lucky to have that panel.

 

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5. ISRO INTERVIEW – 2016

DATE OF INTERVIEW: 22.8.2016

VENUE: SPACE APPLICATION CENTER (SAC) AHMEDABAD POST: SCIENTIST C IN MECHANICAL ENGINEERING

I had to report to SAC early in the morning at 8:00 AM and was the first person to get interviewed that day. After checking the required documents which they do it very stringently, I was allowed to wait near the conference hall. The interview panel consisted of 6 distinguished scientists (1 female member) and the chairman of SAC, Ahmedabad. It was one of those long oval shaped conference tables with the chairman sitting at the center at one end. I was told to sit at the other end but only briefly, as I had to explain everything on the white board. Before I start saying anything, fooling them is impossible and it is you who get fooled if you try to make a fool out of them. Each panel member is specialized in a specific topic in mechanical engineering and the complete panel covering the whole.

My interview started off with the chairman asking why I wanted a job at the ISRO as my current job (working with Mahindra & Mahindra then) was already in R&D and the company seems to have good future ahead. I was already prepared for this sort off question and replied by saying that I was interested and following Space technology right from my secondary schooling and backing it up by talking about the milestone achievements in the recent past (Chandrayan, Mangalyaan, RLVs, Cryogenic Technology GSLV Mark 3 etc.). Once I was all set and comfortable he asked which topics did you prepare for the interview? I said Heat Transfer, Thermodynamics. Fluid Mechanics. Then comes the first question: what is viscosity? What are Newtonian fluids? What are different types of Non-Newtonian fluids? Easy-peasy I was able to answer it in a blink with my confidence ever growing. The next question was to draw the shear stress – strain diagram for these fluids. Was able to comfortably draw it. Then he asked to draw for an ideal fluid. I told it would lie on the x-axis for which he nodded then asked where would a perfect plastic fluid lie to which I immediately said on the y- axis. He told me to think again to which stupidly I again said on the y-axis. Then he asked what a perfect plastic fluid is and helped me in correcting my answer.

After the chairman, one of the scientists took over and asked me to write down the generalized 3-dimensional conduction heat transfer equation which I donno how on earth I fumbled. I was confused with the alpha term (whether it was alpha or 1/alpha) and I wrote the time derivative raised to the power 2 instead of 1. He told me to correct the equation if any. I corrected the alpha term right away by explaining how the equation can be derived but didn’t change the time derivative term, although I have noticed it as it was a blunder and praying they wouldn’t notice as it’s a long equation. He asked me to derive the 2 dimensional transient heat conduction equation which I have last studied 3 years ago. I was barely able to put down the generalized 2 dimensional equation and the boundary conditions. I was not going any further and already started to feel the nerves. Another panel member took over and told I was doing great till now and to calm down. Then he asked me to design a vessel to store a liquid of certain volume. I said I’ll be needing the density of the fluid and yield of the material to determine the thickness of the cylinder and later can decide upon the radius and length of the cylinder. The panel asked why I chose a cylinder why not any other shape. I said as there are no restrictions why not a cylinder as it can easily be made. He said if I want to put a cryogenic fluid into the vessel which shape should I choose. I’ve said I would try to minimize the heat transfer for such a vessel and so it should have less area. He didn’t give me much time explain and said sphere was the answer which I already knew as it has the least surface/volume ratio. Then he asked which material I would choose? I told Stainless steel etc. can’t be chosen as extremely low temperatures makes them very brittle. To which he nodded and said yes, but we use a different grade of steel which can withstand such low temperatures. Then there were some series of questions about stainless steel and its properties (values of yield, UTS etc.).

The final set of questions were asked by the female member in the panel. She asked me to draw a vessel. This time I have asked which type of vessel? Cylinder? Sphere? What is the radius, length and type of fluid? It was a normal cylinder with water filled in it she replied. Told me to put an orifice on the side wall at distance x from the bottom and asked me to draw the path in which the water would leak. Then told me to put another orifice on the side wall at a distance y>x from the bottom and told to draw the path. I drew another parabola. She asked me if these water jets intersect. I have said yes, they might intersect. To which she asked at which point will they intersect? I have told her how to solve it. She then told what happens to this water jets if a heater is placed in between i.e. at a distance z>x and z<y? What will happen to the point of intersection? I have answered partially by saying that the density will decrease and so the pressure at the bottom and hence the range of both the jets will decrease. But could not confidently talk about the point of intersection.

The whole interview lasted for 15 – 20 minutes. It was an experience which I never had before and will remember for the rest of my life although I’ve failed miserably which I knew straight away walking out of the interview. My Suggestion would be to revise the basics thoroughly of 3–4 fundamental topics in mechanical engineering and to speak confidently irrespective of whatever you say and not to trick the interviewer.

 

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6. ISRO INTERVIEW – 2017

DATE OF INTERVIEW: 7.10.2017

It was a Purely Technical Interview.

*Around 8:30 AM* I was second in the list to be interviewed (list was prepared based on Roll No.) , It began at 8 AM with approx 15–20 minutes per candidate.

Two Interviewers were there say I1 and I2.

There were two recruiting officers too who were doing document verification in the next room. Recruiting officers were friendly and one of them even greeted me “All the best” while I was waiting for my turn outside Interview Hall.

*Me enters the Hall*

Me: Good Morning Sir!

I1: Good Morning Dharmesh! Where you did your schooling from?

Me: Sir, Class Xth from Chhattisgarh and XIIth from Rajasthan.

I1: Both CBSE?

Me: Yes Sir.

I1: Tell me your favourite subjects? We will ask questions on that.

Me: Heat and Mass Transfer.

I1: Is it like HMT Professor is really good or what? Everyone says HMT: P

Me: Definitely the professor is really good. He has now shifted to IIT Dharwad and apart from that my internship was related with HMT.

I1: Just one favourite subject in four years?

Me: No Sir, You said best: P

I1: No, not best, favourite!

Me: Fluid Mechanics, Kinematic and you can add thermodynamics too.

I1: Okay.

*Me and my batch mate Chaitanya who was interviewed just before me were having Same B.Tech Project*

I1: So you are working on Solar Paddy Harvester with Chaitanya, Right?

Me: Yes Sir. We are working as a team.

I1: What are your contributions as well his in that?

Me: Explained.

I1: So tell me about Solar Paddy Harvester?

Me: Informed about our objective of bringing down combined harvester cost by replacing it for specifically paddy and using renewable source of energy.

I1: How many members are there in the team?

Me: Just two members sir, He and me.

I2: So you are working on Solar, tell me what Heat Flux is!

Me: Answered.

I2: What is its unit?

Me: J/s.

I2: It is not correct. Something is missing.

Me (Immediately): Yes Sir, I missed area term. It is W/m^2.

I2: Now it is fine. Draw Heat flux variation with wavelength.

Me: I started drawing Wavelength Vs Temp Curve as that was something I was sure of.

I2: Interrupted! Draw Heat Flux Variation with Wavelength!

Me: With some thought, made the curve.

I2: Now tell me what will happen if temperature will increase.

Me: Explained in brief. It will shift up.

I2: If a body is at 1000K and other at 2000K, which will have higher wavelength?

Me: As per Wein’s diplacement law, Lower temp body will have higher wavelength.

I2: Ok

*Actually he was trying to hint me that your curve will shift upwards but leftwards too.*

I2: What we get from area of this curve?

Me: Could not answer. Sorry Sir.

I2: It is fine.

I2: Mention units of X and Y axis.

Me: Mentioned.

I2; Y axis units are wrong. Ok leave it! Clear the board.

Me: Rubbed the board and returned to my seat.

I2: Do you use smartphone?

Me: Yes Sir.

I2: Tell me, how GPS works, and just basic logic?

Me: Told about tracking of change in coordinates w.r.t. time and calculating velocity and acceleration accordingly.

I2: *Interrupting* I want to know how it works, basic logic, Ok let me simplify, tell me if I have to measure length of wall from you without using scale, How will I do it ?

Me: Told about sending waves and tracking in how much time it come back and calculating distance accordingly.

I2: Yes! There is a specific name of this technology, what’s that?

Me: 20 seconds sir, Let me recall.

*They gave few seconds but I cannot recall*

I2: Not a problem, have you heard of RADAR?

Me: Yes Sir, I was knowing, I just cannot recall! Sorry. Told about using ultrasonic sensors to detect distance and alert rider in one of group projects. *Similar to RADAR*

I1: Tell me what is SERVO Motor?

Me: Told that it is used for precise and accurate control usually in range of +-90 degrees.

I1: That’s not the definition, every motor is used for precise control!

Me: Tried to explain how it is different from Gear motor.

*I1 was not pretty convinced*

I2: What is difference between Centripetal and Centrifugal Force? Can they act on a body simultaneously?

Me: Explained!

I2: Tell me difference between Governor and Flywheel.

Me: Explained about Flywheel in a bit detail. For governor, i could not recall much so just said it is use for pressure control, don’t remember much.

I2: Asked about factors to be considered for designing flywheel, like mass, stiffness and other things.

Me: Told about less mass for less inertial loss and High Moment of Inertia (*was not pretty sure about I*) thus high radius. Told about disc plate selection.

I2: How it stores energy?

Me: Explained about storing of energy in form of Kinetic energy by increasing angular velocity. Tried to explain with example of regenerative braking system development.

I2; how angular velocity gets changed?

Me: Told that there are mechanisms (*not having much idea, I guess he wanted to hear angular momentum conservation but I could not recall that at time*)

I2: What is product moment of Inertia?

Me: Explained integral formula that too not clearly.

I2: What is its significance?

Me: *Tried but neither he nor I was pretty happy with the explanation*

I2: What is Nusselt no.?

Me: Explained in detail.

I2: Practical example.

Me: Anything having Convection more than conduction.

I2; Give me Practical example.

Me: Anything with forced convection.

I2: Okay.

I1: One last question, how can you join two objects without using Nut Bolt fixture?

Me: Welding

I1: More?

Me: There are different types of welding like Spot Welding, Stick Welding, and TIG, MIG etc.

I1: Tell me basic definition of welding.

Me: Said about melting of area and then melted part getting fused.

I1: OK

Me: Thank you Sir.

*Interview went for around 20–22 minutes*

*After Interview, I went for Document verification and those officers (say R1 were and R2 were quite friendly). R1 asked about my residential state, questions asked during interview than R2 started praising IIT (his son or daughter is preparing for IIT).*

Result: Rejected!

 

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7. ISRO INTERVIEW – 2017

VENUE: NRSC, HYDERABAD

POST: SCIENTIST/ENGINEER ‘SC’ (MECHANICAL)

I qualified for isro interview thorough written test. Initially I was so scared to give the interview but the panel made me feel comfortable. They asked me about my project. I explained it on the white black. The chairman asked the questions from the project and also from the subjects related to it. My project is on the super vacuum condenser. As I am good in heat Transfer, I answered all the questions. Then another person asked me about the aerospace materials and I said that I don’t know anything about those.

Interviewer: guess

Me: aluminium

Interviewer: why

Me: light and resistant to corrosion

Interviewer: list out the materials which are not conventional

Me: don’t know

Interviewer: what is the material that is commonly use?

Me: steel

Then he asked another person to continue

Interviewer: types of springs

Me: torsional, compression and leaf springs

Interviewer: draw the spring with all the details

Me: drawn

Interviewer: define free and solid lengths

Me: explained on the diagram

Interviewer: what is spring index?

Me: explained

Interviewer: range of spring index

Me: 4 to 8

He asked another person to continue

Interviewer: to machine 50 mm diameter hole with close tolerance, which machining progression will you use?

Me: reaming

Interviewer: list out another

Me: I confused here, he said 50 mm but I thought it is of 5 mm. So, I said wire Edm.

Interviewer: we can do it by conventional machining also.

Me: since I thought 5 mm as hole diameter, I didn’t tell drilling. I said broaching.

Interviewer: nope

Next Interviewer

Interviewer: tell me the machine elements use for automobile suspension.

Me: springs and leaf springs

Interviewer: some more

Me: don’t know

Interviewer: type of springs used in clocks

Me: don’t know

End of the interview

So, my friends, prepare project and associated subjects. Regarding Technical, they mostly ask basics.

 

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8. ISRO INTERVIEW – 2021

DATE OF INTERVIEW- 08.02.2021

PLACE- DEPARTMENT OF SPACE (DOS), NEW DELHI

MODE OF INTERVIEW- ONLINE

RESULT – SELECTED

INTERVIEW MARKS— 83.43 OUT OF 100

Due to COVID, interviews were conducted online at different ISRO Centers which are there in almost all major states. So the interview was going in the conference room of newly build DOS Building at fifth floor in New Delhi. I was called there at 8:30 AM along with 10 other students sharing same time slot. There was tight security at the office gate as it is a sensitive area and we were allowed to take only our documents and a water bottle( Mobile phones were strictly not allowed). Only 5 things were asked in documents by HR (Call Letter, Self Declaration, ID card xerox, TA Claim with tickets, Covid Report). No original documents were checked, however I took them with me. I was fourth candidate to be called for the interview. As soon as I entered the conference hall, there was a big LED Screen and opposite to that there was a long oval shaped table and a chair was directly in front of LED screen around 5-6 meters away from the screen. There was a whiteboard just behind my chair. Cameras were placed in front of LED Screen facing the chair and there was in build speaker on the table and a microphone for candidate to speak. The LED screen had scientists connected from different ISRO Centers( approx. 5 divisions of LED screen) , just like a typical zoom meeting.

 

From now on, I would be referring to interviewing scientists as S1,S2,S3,S4 and S5 as per the number of LED screen division. S1 was coordinating the entire interview so it is safe to assume that he was the chairman of the interviewing panel. HR wasn’t there as per my knowledge in RAC interviews, he/she might be there in other discipline. I would be writing narration in “bracket” in between for you to understand what was going on during the interview. I would be writing some “TIPS” at the last especially for this online interview. So, here it goes like this.

 

I went Inside and stood beside the chair.

 

S1- You are *******, right?

Me-Yes sir.

S1- Please sit down.

Me-Thank you sir. (Touched my mask and whispered slowly , Can I remove this?)

S1(Heard it- Good quality microphone)- Yes, you can remove your mask.

S1- So, Mr. Chinmay, can you tell us about yourself in brief?

Me- Yes sir. So my name is *************…..blah…blah…blah…told them about my native place, schooling, engineering college and the job I did after my college and why I left it. I told them this is my brief ( took about 30-40 seconds only), if they want to know anything else in detail, they can ask.

S1- So, ****(by seeing my soft copy of biodata), you have done some project regarding cooling systems , can you tell us in brief what you did exactly?

Me- Yes sir, so my project was to design and analyze an active cooling system for cooling small areas, maybe an electronic chip by simulating a Concentrated Photo Voltaic(CPV) Cell. The project was mainly focused on designing a 3D model of the entire cooling circuit and doing software simulation on it to measure process parameters. We had initially planned to practically build a cooling loop, but we couldn’t do it and only did analysis through software.

S1(Interrupting)- Okay, okay, you have used some microchannel for it ,right? What was it?

Me-( I forgot to mention that the main component of heat sink was a microchannel which was written in the biodata)- Yes sir, we used a straight rectangular microchannel for the heat sink and reason for using it was its small hydraulic diameter and Convective heat transfer coefficient going as high as 5000-6000 W/m2K. So, we were able to reduce temperature of source(CPV Cell) from 110 Celsius to 80 Celsius. Also…..

S1(Interrupting)- Okay, okay, they would be enough. One more scientist sitting with S1- You have heard about refrigerant R134a right? What does ‘a’ stands for ?

Me- Sir, the “a” in R134a stands for isomer having same chemical formula but different structure, while some refrigerant has capital A, which stands for different compositions

S1- Okay, what is the formula of R134a?

Me-(Started making the formula in mind)- sir, its C2H2F4.

S1- Okay, where is the difference in structure of bond in R134a? Where is the bond….?

Me-( Couldn’t comprehend what he wanted to ask)- Sir, could you repeat what you asked?

S1- Asked again

Me-(I still didn’t understand what he actually want to ask) Sir, Do I need to draw structure of R134a?

S1- Okay, leave it, leave it. You have told the formula. That will do.

S1- Okay, I am done. Over to you S2.

S2- Hello ****, Are you able to hear me?

Me-Yes sir

S2- Let’s talk about glass as an insulator. Can you tell us why it’s not recommend to have too many glass structures in refrigeration system?

Me- Sir, it’s because of Solar Heat Gain in glass structure. Also many glasses absorbs short wavelength radiation but prevent long wavelength radiation to escape increasing sensible heat load in refrigeration system.

S2- Okay, very good. So, in glass there are normally two layers of material. Can you tell what is there in second material……( I didn’t understand again what he wanted to ask. His voice was heavy and ecoing)

Me- Can you repeat sir?

S2-Repeated

Me-(Still didn’t understand what he actually wanted to ask)

S2-(Observing my expressions) Okay, leave it. Have you heard about multilayered insulations?

Me- Yes sir. As the name suggests, there are many layers of insulation material arranged in a special pattern for insulation. The same golden color foil that we see wrapped around the satellite is multi layered insulations. It is made of polyamide and has layers of….…..

S2(Interrupting) – Okay, excellent. So, One side of satellite faces the earth and one side faces towards the sun. Can you think of something that can be used for cooling system exploiting such condition?( A good practical question)

Me-(Thinking for 4,5 sec)- Sir, I can’t particularly think of something at this moment.

S2(Giving Hint) – Have you heard of heat pipe?

Me(Got excited)- Yes sir, yes sir. Heat pipes can be used here as it is a device which is both condenser and evaporator at the same time. It is a hollow tube having wick type material and a medium gets evaporated and takes heat and dumps heat at other side. One side acts as evaporator and once side acts as a condenser. So, it can be used in satellite.

S2- Okay, very good. I am done. Over to you S1.

S1- Okay, S3, now you can take from here. Over to you.

Now , I am just writing the questions. Similar approach was followed as above between different interviewer and the candidate.

S3-What are the different types of condenser and evaporator? Which one is more efficient? What are the general properties of refrigerants? What are the current refrigerants used? How ammonia fare as a refrigerant? What is its discharge temperature with respect to other refrigerant? What is the unit of Refrigeration? How liquid nitrogen is used practically for refrigeration?

Me- Answered all.

Over to S4

S4- Have you heard about inverter AC? How we control speed of compressor in refrigeration system?

How will you increase efficiency of a fin?

Me- Couldn’t answer about controlling speed of compressor. Rest answered.

Over to S5

S5- What is Aircraft refrigeration system and why it is specifically used? What is COP of Aircraft Refrigeration and why it is so less?

Me- Answered point wise and gave detailed answer

S4(Interrupting) – Okay, okay. That would be enough.

Over to S1

S1- Okay ******. I think we are done here. You can leave. All the Best.

Me- Thank you. (I had one genuine doubt regarding maintaining low temperature of vaccine that was in my mind for some weeks, so I asked them. It wasn’t planned but it just came out of my mouth intuitively and they answered it.)

Left with a big smile as got good feeling after the end of interview J

 

Tips for Online ISRO interview

• Tip1- Better not to tell too much about “yourself” and keep it short and simple, as they have to take a fixed number of interviews planned in a day and they just want to know a little background about you.
• Tip2- Try to answer point wise or precise. If you lengthen the answer of even simple definitions and start explaining in details(Even I did this for some simple questions),they will keep interrupting. They have to complete 25 odd interviews in 1 day.
• Tip3-Among things mentioned in bio data form, there are fair chances that they will ask about your project, more chances if the project is related somehow to the area where ISRO works. So, play to your strength and answer those part of your project which you can explain. Don’t use some high profile term while explaining anything, otherwise they will ask question from that. Rest things in Biodata, they might or might not ask. Don’t worry too much for gaps after B.Tech.
• Tip4- 70-80% questions will be from basic definitions/properties/advantages/disadvantages/salient features/assumptions, etc. Only some good questions they ask. If you get struck in them , they might give you hints. Try to catch that and answer. A lot will depend on your understanding of basic concepts and aptitude to answer such questions.
• Tip5- For online interview specifically, even though ISRO had good arrangement of equipment, still you might not be able to understand some of the question due to accent issue, heaviness in voices of some interview panelist or some echoing problem. Respectfully ask them to repeat the questions. They will do it.
• Tip6- ISRO interviews are like a rapid fire round . But during online mode, the firing speed of questions will reduce compared to offline and you will get to answer the question in some details( as you can observe in above discussion). There was a white board behind me but they didn’t ask me to use it. They may/may not ask to use it.
• Tip7- If you are not confident about online interviews. It’s better to practice mock “question and answer” before web camera or phone and record it and see the recording to know what can be improved. I did this for 3,4 days before interview half an hour daily. It actually gave me confidence.
• Note- The entire experience is with respect to RAC online interview. There might be some change in way of asking questions in upcoming branches interview. But yes, arrangement and approach will be similar. So, anyone can take a basic idea about the atmosphere there.

This is all I had to say. I have wrote everything in details only because candidates have apprehensions regarding “Online” Mode of interview in ISRO. I have tried my best to explain entire atmosphere and arrangement during the online interview. . Feel free to ask if there is anything else.

 

Thank You.

 

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9. ISRO INTERVIEW – 2018

DATE OF INTERVIEW- 23.2.2018

PLACE- ANTIRKSH VIHAR, DWARKA NEW DELHI

There was 10 panellist including Director , sitting on U shape table.

Director- Be comfortable , have a seat.Give your introduction.

M1 : what are your favourite subject.

Me: Fm, som , thermo , power plant, HMT, Turbo machine

M2: we are listening these subjects from morning , tell us some other subject like machine design, material science , production , theory of machine

Me: machine design and theory of machine

Director: theory of machine , pointing towards expert member in theory of machine.

M: Go to white board , take marker from table..

M: what is degree of freedom.

Me: answered

M: draw a pendulum attached with a string on board.

 

Me: drawn

M: what is it’s degree of freedom.

Me: Two

M: How??

Me: I said if I consider stiffness of string also than pendulum can move in vertical direction due to difflection of string and pendulum can also rotate in the plane of board about hinge point.

( They appear impressed because generally we reads one dof of simple pendulum, when I said two , their facial expression was such that I am wrong but when I justified answer ,they impressed.)

M: what is the degree of freedom if I consider the string as rigid?

Me: One

M: what is energy conservation. Write energy equation for this.

Me: answered and written on board.

M: where will be maximum velocity , where will be acceleration maximum.

Me: answered

M: what is the acceleration when it is in middle position.

Me : Answered

M: Attach a spring in placeof string , how will be the motion of this .

Me : same as in case of string with considering the stiffness . It wil have to independent translating and rotatory oscillation.

Director: Draw a horizontal beam

Me :Drawn

Director: assume this is massless , attach a beam perpendicular to this beam at one end having mass M , joined by welding. Rotate this beam with angular velocity omega. Design the beam for welded joint.

Me: sir the beam must be hinged or attached somewhere for rotating to balance centrifugal force.

M:(one old member smiled and appearing impressed) – yes it must be attached , hinge it from a point.

Me: drawn the free body diagram , written moment on joint . Calculated stress ( one minor mistake I have done I assumed different length of beam but in equation I wrote same, one member was hinting me but I was busy in solving question)

Director: draw equivalent cantilever beam and load diagramof this beam.

Me: I was drawing ,half drawn.

M: ok leave it

M: how will u measure the height of chimney.

Me: sir with the help of lasor.

M: No u have no instrument. Only u r there.

Me: silence

After thinking 30 second , sir with the help of my shadow.

M: how

Me: expned with drawing triangle of my shadow and chimney shadow.

M: Now u r on Top of chimney , how u will measure now

Me: again silence….after thinking 50 second , sir I will drop something from the top of chimney , and calculate the height with the help of time to reach down.

M: ok( one wonen member smiled, appearing impressed) they are checking presence of mind.

M: derive formula for falling time and write the equation for time.

Me: done

Director: Ok now u can go

I not listened clearly , I sat on the chair again.

M:. Ok u can go.

It was 20 minute interview , they check your basic understanding of concepts and their application in real problems. Sometimes they may check ur presence of mind. The panellist are very supportive , they will also give hint if u r doing wrong or forgot something. Be confident during interview.

Result- I qualified interview but not got place in 35 selected candidate list. I was in waiting list in 4th position.

 

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10. ISRO INTERVIEW – 2017

AIR – 9

I got AIR 9 in ISRO 2017 ,so I think I might answer your question. Now coming to the interview experience it was good and analytic type. Interview started with introduction . I told about my self,my graduation degree and past work exp. First of all let me tell you about my past background. I did B.tech from NIT surat in mechanical engg. and I got placed in FIAT India from there,i worked there for around one year then left job.Prepared for GATE ,went to IIT Delhi then worked as scientist in Institute For Plasma Research ,then got offer from ONGC and currently working in ONGC. So first question was why you want to join ISRO ,you are already working in one of India’s most prestigious PSU.I was expecting this question and knew very clearly that I will need to justify my application and at the same time I should not speak negative about ONGC . So I started about my justification with praising ONGC as well as ISRO,and then slowly told them that although ONGC is finest organisation but I want to work in scientific organisation ,in which ISRO is leading organisation.Next tough question was why u left IPR although it was scientific organisation Under DAE. I told that my post was not permanent there that time.They said”ohh”.They in between try to tell me that you will get lot of money in ongc but I justified with fact that after some time job satisfaction is important and isro money is also decent only. Then they have started to ask Favourite subject. I told Thermodynamics and Heat transfer. The said “and??” . I said “SOM”. Then again said “and??”. I said” TOM”, although I was not prepared for TOM. The worst thing is they started to ask questions from TOM only. There is expert of every subject in the panel.Now the questionnaire started,the asked about how you will calculate degree of freedom of mechanism.I thought it is very simple question and give answer very quickly. Now the the analysis begins about degree of freedom and next they asked “tell me two cases in which kutzback equation is not valid?”. I told the same.They keep asking from questions from TOM then thermo then SOM then some questions from graphs. I answer most of the questions. At last they asked the third angle projection of nearly vertical hollow cylinder. I drawn on white board.They tell me to give unilateral tolerance to dimensions. After a short discussionI came to final answer. They said “Thank you ,u can go”. I said thank you and left the room.

Suggestions:

1. If you are having good concept about subject no need to worry. You will go through the discussion and your concepts will be checked in between.
2. I felt there occurs communication problem because there is mostly south indians in panel. So you should be really attentive during listening question and discussions.
3. Never say anything about you don’t know. They have experience of decades in the subject. So it’s better to say “sorry sir ,I am unable to recall or I don’t sir” then roaming here and there in your answer.
4. Lastly, luck matters. First of all you should be sound in concept but it is also important that questions should be asked from your strong area. It happened with many candidates that questions were asked which don’t belonged to any of the favourite subjects. So, remember God once before entering the interview room and rest believe in yourself.

 

Some important points for ISRO interview-

1. Interview will be purely on basis of technical knowledge (no HR ).
2. They may ask you about yourself and similar questions but that will not contribute any mark for interview that is only for making you comfortable with the interview environment.
3. Prepare everything in depth, superficial knowledge will not end up with success.
4. Rather then preparing all subjects superficially, prepare atleast 4 subjects in depth.
5. There may be some questions you don’t have any idea means exact data or concept or number , for those questions you should give answer according to concepts you have read. In those questions, they want to observe your approach means how you approach toward a problem. Because in reality also , as a scientist you have to design number of things depending upon your concept and approach (for new inventions or experiments of which you don’t have exact idea). But here I am not talking about flukes.
6. Please prepare about your B.Tech project in depth. Most probably they will all ask you question from that area. It’s their favourite area of questions.

*Approximate 10–12 members will be there and many times they will ask you solve or show this question on board (one white board will be there in interview room).

 

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11. ISRO INTERVIEW – 2017

AIR 4 – ISRO ICRB MECHANICAL.

POST: SCIENTIST C

WRITTEN EXAM: DATE: JAN 2020

In ISRO exam there is no Aptitude, GS subjects like GATE and ESE. Only focus on Technical subjects preparation and few questions in engineering mathematics.

ISRO exam is OMR sheet based exam like ESE and not online exam like GATE.(TIP: do not mark at the end in hurry better to solve 1 page of question paper and mark 4-5 questions in a single go, ones marked you cannot change it further).

NO calculator is allowed

Speed approximate calculations may be used by seeing the options.

Study material for practice according to priority:

1. ISRO previous year questions book.
2. ESE prelims previous year questions.
3. GATE 1 marks questions
4. GATE 2 marks questions

do not solve very lengthy problems if your focus is only ISRO

QUESTION PAPER ATTEMPT TECHNIQUE:

I will suggest to solve the question paper in 3 rounds:

Round 1: solve only theoretical questions and questions if you are remembering the answer where

you do not need to touch your pen for solving also just roughly see the level of questions and get idea of the whole paper. It will be completed in 15-20 mins and you may cover around 25-30 questions.

Round 2: solve the numerical questions which you already know the steps to solve and are sure and confident that you can solve within less time.

ROUND 3: solve the lengthy questions which you know first and if time remains try to solve the remaining questions.

Tips: try for elimination if possible.

INTERVIEW:-

(this time it was a online interview at the isro centres)

Date: july 2021

There is a common misconception among student that BARC and ISRO interviews are of Similar nature. I think it is not totally correct.

In BARC they generally ask from your 4-5 favourite subjects only and they start from a very basic question and go to depth , the next question is generally asked from the previous answer given by you and there are cross questions and the interview may take on an avg 45 mins.

You may not practice barc previous year interview questions available on quora for isro interview they slightly based on thinking and time consuming.

(Although i have not given barc interview)

ISRO:

DRESS CODE: light colour formal shirt , dark trousers, black formal shoe, tie may be used, no need for coat

Do speak English because many panel members are from southern part of India

They start with introduction (brief)

(tips: highlight only your strong points, do not mention your b-tech project or training if not done properly, do not mention anything which you are not sure of like m-tech even if done from top IITs if you are not doing it properly it can ruin your interview if you are unable to answer the questions from those areas)

Tell 4-5 favourite subjects( but in ISRO you have to prepare for all subjects including Material science(VERY VERY IMPORTANT), engineering drawing, maths, quality (from GS of ESE ),Industrial engineering which the students generally neglect) most of the time they do not ask all questions from your favourite subjects like BARC INTERVIEW.

In ISRO they generally do not go to depth and ask staight forward questions with max 1-2 Cross question and try to the give exact point in the answer directly without going for too much details so that they can ask max number of questions within the limited time ( avg interview time is 20 mins).

They may ask you solve some questions on the white board and explain

(TIPS: buy and practice on a small white board at home you may get it for around RS 1000-1500, you must speak and explain loudly while writing on board and define all the symbols used and tell assumptions also if few in number, behave like a teacher explaining the students)

If you do not know any questions just say I am unable to recall now do not unnecessarily waste time by giving bluff and fake answers. I have answered around 70% questions and I think quality of answers also matters.

(Tips: even if you know the answer completely do not jump to answer the question very quickly, take 1–2sec pause behave as if you are thinking and slowly frame the answer properly and then answer.)

 

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12. ISRO – OTHER INTERVIEW QUESTIONS (COMBINED-2021 ONLINE INTERVIW).

First time ever online interview. The students were asked to report to one the centres across the India and the panel was situated at every main ISRO centre and connected through a video conference. The size of LED Screen was about half the size of wall. The network connection was not that great and some students faced difficulty in hearing the questions properly.

Important points:

1. The interview duration was 15–20 minutes with topics asked in rapid fire manner.
2. Small derivations and graphs were asked with the help of Board.
3. They asked about favourite subjects but didn’t bother to listen to them and asked from wherever they can.
4. Didn’t care about MTech or Job experience.
5. No focus on the projects what so ever.
6. Unconventional topics like Renewable energy, Metrology, Robotics, mathematics were asked from many students.

Here are some interview experience of the candidates. Hope this will be beneficial to everyone and they can get the hang of the interview process

 

Interview experience Duration -15-16 min

Total material science

1. Tell me crystal lattices of metal ( answered Cubic and Hexagonal mainly)

Inke alava aur kaun kaun se hai wahi orthorhombic and wagereh btaya phir bola metals mainly Cubic and HCP mein hote hai

2. Aur btao wo BCC wagereh ,told about those bravice lattice

3 example of Bcc ,fcc and HCP

4.explain metallurgical defects

5 .types of these defects

6. Explain yielding with the help of dislocation
7. Whether presence of carbon is necessary for yielding
8. What is true stress and true strain and what is difference between Engg stress and strain
9. Two bars are joint in parallel and heated but fixed at both the ends which will have more stress and why ?
10. Write the formula of thermal stress?
11. What is the precipitation hardening explain it on board
12. Various NDT method.( I took the name of accostic wave he told to explain , I said sorry..
13. What is creep

14 what is endurance limit .

15. Types of dislocation

16 draw cast Iron stress strain diagram

17 Youngs modulus of cast iron is more or less than steel

19. Example of precipitation hardening alloy..

 

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14. ISRO – OTHER INTERVIEW QUESTIONS

Interview experience, Centre Lucknow, Date 16/07/2021

1. What is black body
2. What is white body
3. What is NPSH, how it changes with the speed of pump.
4. What is fluid coupling, where is it used?
5. What is solar constant.One more question regarding it though don’t remember.
6. T- s and P V diagram of CI engine, which cycle it follows.
7. Find out the velocity at the bottom of a container when it is open to atmosphere.
8. Find out the velocity at bottom of a container filled with liquid when container is closed, express it in terms of Pressure?
9. What is buoyant force and its magnitude.
10. water freezes at 0° C temp what do we have to do to make the water work at -http://10°C.Name of the anti refrigerant?
11. Types of the stress that develop in a thin cylinder? Whose magnitude is the highest?
12. Where will the failure occur at if the pressure of thin pressure vessel is kept on increasing?
13. What is solar mirror?
14. What refrigerant is used in refrigerator nowadays and why?
15. Joule Thomson coefficient’s significance?

 

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15. ISRO – OTHER INTERVIEW QUESTIONS

Introduce

Q1-What subjects have you prepared

A- td, ms, som, hmt

Q- Draw air standard compressor cycle

A- Made wrong direction then corrected

Q- Write its workdone

A- Answered with explanation of why I wroke gamma

Q- What is value of gamma

A- answer for air

Q- What is superheated steam

A- unabke to give definition, with hints answered

Q- what is boiling point of water

A- answered

Q-again asked the same question with different condion

A- Answered

Q- What is ttt diagram?

A- due to nervpusness unable to explain

Q- what is austenitic steel

A- dont know

Q-draw stress strain diagram for steel

A- answerd with explanation

Q- where is proportional limit

A- showed

Q-what is proof strain, its value

A- answered

I was still standing they asked

Q- we do proof testing, we check strength or proof strength what is that?

A- er… (me confused looking at diagram proof strain and he asked proof strength)

Q- like we do strength testing of pipes, hydraulic and pneumetic what is that

A- again no answer as i dont know why he asked proof after proof strain

Q- Please sit(with name) it is totally a different question, you need not to see the diagram

A- answered about hydraulic and pneumatic testing and its purpose

Q-what is hydraulic coupling

A- answered just the basic

Q-if two bars Al and Steel both fixed at ends and heated, what type of stress, whoch one will have more

A- answered type of stress and said one having thermal expansion coeff more will have more stress,

Q- which one have more alpha,

A-dont know

Q- what is density of Al

A- dont know

Q- if I give u dimension will u be able to measure density

A- answered

Q- if I dont give dimension can you measure the density

A-answered

Q- how do u measure angles

A- bevel protractor….(stopped me)

Q- can you measure angle of the corner of this room with bevel protractor?

A- i said never used it so cannpt tell you whether I can use it or not

Q- can you measure it even without it

A- answered

1. N. D.

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16. ISRO – OTHER INTERVIEW QUESTIONS

1)Introduction

2) how to choose element in fem

3) how ro ensure results r right?

4)Difference between bar and beam element

5)Difference between shell and plate element

6) Difference between plane stress and plane strain condition

7) Draw Sfd and bmd for cantilever subjected to uvl

8) can beam element captures axial deformation?

9)Applications of plane stress and plane strain element conditions

10) What is hole basis and shaft basis system

11) Difference between 1st and 3rd angle projection

12) why hatching is used in drawings

13) Is there any situation we don’t represent hatching though we cut solid?

14) H7/d4 belongs to which type of fit

15) why Aluminium will be chosen

16) What r the Properties of Aluminium

17) Tell me about Aerospace materials

18) Fastener representation

19)How to apply torque over nut (is it hand tight always or what ??)

20)What is the percentage of initial load on bolt

21) Where we use coarse and fine threads

22) what are classes of bolts?

23)Techniques to prevent bolt loosening

24) On what basis bolt classes are classified??

 

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17. ISRO – OTHER INTERVIEW QUESTIONS

1-Draw vapour compression cycle

Name all process

2-What will happen if vapour is superheated after comprehension.

Draw curve

3-if vapour is saturated

4- if vapour is below saturation

Effect of all these on cop and ref effect and workdone

5- write linear differential equation

6-How to get solution of these equation

7- Bernauli Eqation in mathematics

8-front view of cutting tool and show lip angle

9-use of cutting fluid

10-effevt of it on tool life and quality of product

11-what is dof

12-dof of monoatomic and diaatomic

13-dof of water molecule

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18. ISRO EXPERIANCES

Date 14/07/2021. Ahemdabad

Introduce yourself

Fav sub SOM, FM, BTD, VIBRATION (They smile when I say vibration)

How are feeling today?

What is metacenter?

Significance of it?

How you decide whether body is stable or not?

What are the hydraulic machine?

Tell me more

More

More(ab kya batavu bhai esa hone laga)

What is turbine?

Draw velocity diagram for turbine?

Design turbine blade?

This not you can do? Leave it…

Draw cantilever beam?

Give difference complex loading then try to draw add bmf

What if this beam is fail?

Chairman sir ( with tea and vaffer)

Temperature time diagram

No no TTT diagram?

What is heat treatment process?

Tell me NDT process?

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19. ISRO – OTHER INTERVIEW QUESTIONS

13/07/2021 : 8:30 @ SDSC SHAR

#MEMBER 1 :

1).Stress Vs strain for Ductile with points

2). Stress Vs strain for Brittle

3). E value for elastomers

4). Modulus of resilence , Modulus of toughness

5).Cantilever with UVL ,draw SFD and BMD

#MEMBER 2:

6). How can you transmit the power between any 2 shafts

7).Hooks joint where you find?

8).Types of bearings

9).bearing specification SKF 6205 ZZ …explain terms each

10). Above specification indicates which bearing?

11). Angular contact bearing taken which load most?

#CHAIRMAN :

12)..what is Cast iron?

13).CI advantages disadvantages

14).CI application

 

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20. ISRO – OTHER INTERVIEW QUESTIONS

Fav subs: Thermo, IC, SOM,FM

Tell me about yourself

Resilience

Specific strength

Elastic modulus definition

Modulus of rigidity

Draw sfd and BMD for cantilever with point load

Write bending stress equation

Why we use gearbox

Law of gearing

Type of gear profiles

Difference bn cycloidal and involute

Draw an I section and calculate moment of inertia

Mark the perpendicularity and surface finish on one of the views of the I section as in engineering drawings

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21. ISRO – OTHER INTERVIEW QUESTIONS

.12/07/2021

1. What are the theories of failures ans superimpose the safe area of each?
2. Write the stress expressions in Springs and tell me which factor will affect the most in increasing the stress?
3. Buckling governing equations, not the formula?
4. An unloaded fixed beam and one support is moving? Tell me how you find the reactions and moments?
5. Draw true stress and true strain curve? Does that yield point phenomenon happen in both cases?
6. Roughness Waviness?
7. What are the reasons to have roughness on the surface? Told two..they said more.
8. What method to represnt it? And which one will give you the highest value of roughness? Initially I thought methods to measure it but they corrected by saying its representation like CLA and all.
9. What is friction? What are static and dynamic friction? Which coefficient is high and why?

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22. ISRO – OTHER INTERVIEW QUESTIONS

12/07/2021 His Mtech project is in Noise and Vibrations.

1. Introduce yourself
2. Write laplace equation of heat conduction for 2-d
3. Solve it by numerical method( fem)
4. Critical radius of insulation
5. Application of critical insulation and why it happen
6. How you reduce noise in a system
7. Noise generation methods
8. Transmission loss vs frequency
9. Transmission vs frequency
10. Natural frequency formula
11. Forced frequency formula
12. What is Critical damping
13. What will happen to amplitide at resonance
14. Why damping is used
15. Vibration is bad or good phenomeon.
16. What is response of a thermocouple
17. What 63% in time response
18. Write lumped heat analysis equation (exponential decay)

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23. ISRO – OTHER INTERVIEW QUESTIONS

Interview experience 12/07/20 dehradun

1) what is vibration and what is shock difference between them

2) draw a graph between transmissbility and angular velocity ratio for zeta=0

3)what is damping factor and what is critical damping coefficient

3)is it possible to eliminate vibration completely

4)tell some casting processess

5)what is difference between investment casting and sand casting

6)tell some casting defects and what is coldshut

7)what is additive manufacturing and what are the processes involved

Interview duration is about 14-15 minutes.

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24. ISRO – OTHER INTERVIEW QUESTIONS

interview 9/07/21

fav. sub. fm, som, ht, btd

1)what is FOS of mech.

2)what is redundant dof.

3)dof for gear box of car.

4) write flexural equation

5) derive it

6)what are forming processes?

7) what is HERF? name of different techniques?

where it is used.

8) body is in international space station modes of heat transfer invoved?

9) does convection occur?

10) what is grashof no.

11) forces involved in free convection)

12) which refrigeration system you will use in space ?

13) what is reliability ?

14) bath tub curve?

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25. ISRO – OTHER INTERVIEW QUESTIONS

Date 8 july, 2 pm

I1-

resilence

Toughness

Bulkmodulus

True strain

Propedd cantilever rxn calculate

I2

How we made self lubricant bearing

How hollw tubes

How wires are made

Flat plate

Complicated shape

I3

Different between first n third angle

Tolerance

Types of tolearnce

Geometrical tolerance

Difference between tolerance and allowance

Material used in crygenic application

Lady ask-

Layers of atmosphere in order from sea level

Pressure variations

Temperature variation

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26. ISRO – OTHER INTERVIEW QUESTIONS

interview experience 10/07/21

brief introduction

fav. subject

1) what is perspective view. what is difference between perspective and parallel view.

2) auxillary plane ?

3)what is universal beam? draw

4)type of loading ?

5)stress variation in ractangular beam.

6) fatigue limit for different materials

7) draw for both ferrous and non ferrous

8)what is cauchy rehman equation.

9) use of it.why ?

10)where u have seen in ht?

11)what is gauss divergence theorem . application?

12) dot product and cross product. application

13) what is temper embrittlement.

14)how to reduce it.

15)which structure has large solubility of carbon and why?

time around 20min.

voice was not clear, breaking in between u have to tell them multiple time to repeat the question

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27. ISRO – OTHER INTERVIEW QUESTIONS

Reporting time 2:00 PM.

Entered at 1:30 PM

Except documents and wallet nothing was allowed inside the centre.

After some formalities at entrance we entred to waiting room.

A beautiful ma’am was verifying documents so we ( specially I, ) didn’t feel bored while sitting there for approx 3 hours. My turn was on 28th of the day ( 8th of that shift)

1. We can’t see you hitesh, please come near to the chair and have seat.
2. Tell me about yourself in brief.
3. Fav subjects – basic thermo HT Fluid Som
4. Can you draw mohr circle for pure shear stress acting on a block?

Drawn

5. Reporting time 2:00 PM.

Entered at 1:30 PM

Except documents and wallet nothing was allowed inside the centre.

After some formalities at entrance we entred to waiting room.

A beautiful ma’am was verifying documents so we ( specially I, ) didn’t feel bored while sitting there for approx 3 hours. My turn was on 28th of the day ( 8th of that shift)

Interview

1. We can’t see you hitesh, please come near to the chair and have seat.

Tell me about yourself in brief.

Fav subjects – basic thermo HT Fluid Som

Can you draw mohr circle for pure shear stress acting on a block?

Drawn Show principle strees – did

what are the values – did

Can you show stress element – did

Where will principle stress will occur inside the block – did

What are principle stresses – told

Can you write equations of principle stresses , i said should i write only equation or drive it. Then said write only equations.

Can you show variation of shear stress on a beam cross section- i assumed rectangular and draw

There are two sections one is square and other is circular.. in which cross section maximum shear stress will be least ( thoda time lga question smjhne me par ho gya to bole good).

What is true strain write expression for it.

Make stress strain diagram for mild steel in compression and tension… Tension me to bna diya but compression me nhi bnaa bhul gyaa…to bole ki chlo bas ye btaa do ki yield stress tak kya hoga compression me to ye bhi nhi bnaa mere se..

Fir member change ho gyaa

What is the sonic velocity , what is the formula , how can we increase it,

Do you know about mach number

How will you increase the velocity to supersonic from subsonic.. i said with the help of C-D nozzle.. bole board pe smjhao… Pressure distribution btao iska..

Diverging part me velocity and pressure dono hi kse bd rhe hai..mai bola density change ho rha hai so to keep the mass flow rate constant we have to increase the velocity and area increase ho rhaa to pressure bd rhaa..

Fir bole ki agar diverging part ki length ko aur bda diye jaye to kyaa pressure reservoir ke pressure ke equal phuch jayega ?

Yha pe mai fir se atak gyaa fir bole you may leave hitesh thank you.

Total interview time about 20 minutes.

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28. ISRO – OTHER INTERVIEW QUESTIONS

11 AM slot, my turn came around 3:15

Introduce yourself (they don’t even focus what you are saying)

Fav subjects?

TD, SOM, HT, RAC

Q1. There is a shaft of dia 50mm and turning operation is being done on this shafy, the process is normally distributed with SD 0.1, tell me the probability that final dimension of shaft will be 50 +- 0.3

Q2 What is creep?

Q3 Draw creep curve.

Q4 Draw the creep curve for increased and decreased stress.

Q5 Draw a triangular member, and on the base a weight W is hanging, top is attached with belt and pulley which is attached to the crane hook, tell me the stresses generated in the sides of the triangle.

Q6 There is a PV and an external pressure is acting on it, tell me the methods to increase its buckling strength.

Q7 What is L/D ratio for PV?

Q8 Why ends of PV are made hemispherical?

Q9 Between MS and High carbon steel, which will have high weldability.?

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29. ISRO – OTHER INTERVIEW QUESTIONS

Interview exp- 06/07/21

Around 20 mins

1. Introduce yourself
2. Fav subjects- FM, HT, SOM and TD
3. Classification of heat exchangers
4. Convection heat transfer and significance of prandtl no.
5. Development of flow in pipe
6. How to determine thickness of pipe in terms of pressure drop and discharge/average velocity
7. Explain quality and reliability
8. Difference between selective assembly and interchangeability
9. Diff. between a measurement device and comparator with examples
10. What is balancing and why do we do it.
11. Types of balancing.
12. Motion transfer mechanisms
13. Where to use gears, belt pulley and chain sprockets mechanism.
14. Advantages and disadvantages for gear train used in place of chain sprockets in bicycle.
15. Why alloy wheels are not used in bicycle.

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30 ISRO – OTHER INTERVIEW QUESTIONS

Isro interview venue: New Delhi 03/07/2021 8:30hrs

7 panel members in which one madam and one chairman with 5 interviewers. Chairman said: introduce briefly. And before they asked I mentioned favourite subjects at the last of introduction.

Chairman refers to I1.

I1 asked from SOM.

1. What is helical spring?

2.which types of energy stored in it potential or kinetic types.

3. If we applied gradual load W it elongated X .then how you will find stored energy?
4. What is principal planes and principal stress?
5. If on a point body loads are acting and we found principal stress in all the planes then which planes contains max. Shear stress and how to calculate that max. Shear value?

Then I1 refers to chairman and chairman refers to I2.

I2 asked from FM.

1. What is laminar and turbulent . Which parameters define the fluid behaviour.
2. If laminar is flowing through channel how you will covert into turbulent without changing its channel size and fluid & flow properties?
3. If turbulent flow is there in place of laminar (in 2nd question) how to convert into laminar with taking above conditions.

4.Streamlined body.

5.define compressible and incompressible flow? Which dimensionless no. We take as deciding factor for compressibility.

6. What is Mach no.

7.as you told ‘Re’ and ‘Ma’

Do you know any other dimensionless no. And why we read that other dimensionless no.?

Then I2 refers to chairman and to I3.

I3 asked from engg. Drawing.

1. Diff. B/w 1st and 3rd angle projection.
2. In both angle of projection where side view is placed right or left side.
3. Diff. Between perspective views and isometric views.

Then last I4 turns he asked from Meteorology.

1. What is tolerances and its types.
2. Tell types of fit .
3. Give examples of these fit.
4. Tell we want to made cylinderical hole shaft arrangement .what are the process involved in it?
5. If shaft is not going inside the hole then which device is used to made it assembled.

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31. ISRO – OTHER INTERVIEW QUESTIONS

Briefly introduce

Favorite Subjects :TD,SOM,MS,RAC

1. What is Prandlt Number ? What is significance related to Hydrodynamic boundary layer thickness and thermal boundary layer thickness
2. Different cases Of Prandlt Number and Show it in boundary layer profile
3. In a Copper tube there is washer . Find the stresses in tube and washer . I couldn’t listen the question properly.

4 . What is steam engine and steam turbine.

5 what is Fatigue and Creep

6. What is Poisson’s ratio

And What are the possible values for different materials?

7. Different types of stresses in a rivet
8. What are different types weld? (I thought Fillet weld and Butt weld design perspective as question was after Rivet joint )

Then explained on production perspective.

9 . asked different types of Solid state welding

10 . Difference of Solid state welding wrt other welding techniques

11. What is specific strength . Defined but was not satisfied told write the formula with E

I couldn’t get it . Then told do you know what is stiffness that’s I am asking. I defined stiffness. Asked with help of E .

Then I told Axial stiffness and wrote formula. Still he was not satisfied

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32. ISRO – OTHER INTERVIEW QUESTIONS

Interview exp

fav Sub ht Tom som dme fm

1. Heat exchanger very basic koi bhi bata dega
2. Ejector kya hota hai

Where is Belt drive used

Advantages uski

Petroff eq dme

Yaha tak sahi tha

Iske aage Tom

Draw spring mass damping system

Write it’s eq

Now a load f constant is acting on mass

Now write eq

Find / derive the particular eq of this eq ( gand maar li iss question ne) 10 min le gaya yahi akela nahi hua pura

End

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33. ISRO – OTHER INTERVIEW QUESTIONS

Today’s questions

Q 1. What are the names of different types of crystal structures, with example?

ME,explained , given the eg of iron’s different phases for BCC, FCC but they stopped me then siad other than iron ,

Me Told them.

Q2 What are the defects in crystals?

Me told

Q3 Name of the strengthening mechanisms?

Me told

Q4 What is precipitation hardening?

Me took little bit time to frame the definition in english ,so they changed the question.

Q5 How the impurities are added in crystal structures?

Me could not answer it well.

Q6 what is toughness and how to measure it?

Me told

Q7 what are the different ways of transmission of power between two shafts?

Me told gear,coupling,belt chains etc.

Q explain each of the above ..

Q8 draw a pully system of Mechanical advantage 2

Me drawn of leaver that also reverse then he stopped me, and told me to draw of pully system ,but i was in confusion whether to draw pully in parallel to each other or coaxially of double in diameter so I left saying sorry sir

Q9 what are forced and free vibration?

Q10 what will happen if natural frequency matches with forced frequency?

Me told about resonance and amplitude of vibration will get infinite.

Q but it does not happen practically with the system why

Me could not answer it well

Q11 what are the different properties of cutting tool materials?

Me told

How to get a cone from sheet metal

Me told

Q12 which type of gearing is used to transmit power at 90 degree

Me told mitre gearing but he was not satisfy with that answer may be because I didn’t say worm and wormwheel.

The biggest problem is that in virtual interview there is lack of time to answer properly ,if u think for 3 to 4 seconds meanwhile they asked another question .

Sometimes voice comes little late just like as on whatapp , and then start am i audible to you. So on an average in 20 to 25 minutes u get roughly one and half or hardly two minuts to each question then answering it properly so this create an unbalanced between thinking and then answering,

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34 ISRO – OTHER INTERVIEW QUESTIONS

• Introduce ur self
• Favorite subject ( they will not even ask single question from it favorite question though)
• U came from dehli it’s 40°C now assume there is refrigerator in ur room and ur best friend comes so will u open the door of fridge ? I said no then
• Prove mathematically this on board
• Now ur home is in Rajasthan and u r wearing this beautiful kot then tell me why u will put off in ur desert ?
• What is mechanical advantage? Tell me one practical example of it

7 draw pulley and derive on board mechanical advantage relationship

8. What is throttling? Where u use in daily practice

9.come on board draw mild steel rubber and cast iron stress strain diagram

10.what is the maximum height of centrifugal pump that u can delivery water?

11. What it u goes beyond this height?
12. Derive sphere critical radius formula on board

13.now will u insulation inside or outside ? Outside why outside

14. Tell me one material that will decrease thermal expansion elongation
15. One last question tell me one parameter that is most important in cooling tower that can control Cooling

That’s it

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35 . ISRO – OTHER INTERVIEW QUESTIONS

 01/07, 19:30

Introduction

Fav. Sub.

Fir ht se

Absorptivity, transmissivity, reflectivity, emossivity, poochha

Inme relation poochha

Kirchoff law

Fir rac me compressor kyo use krte hain

Som me

Thin cylinder and thick cylinder poochha

Inme kya principle stress honge ye poochha

[01/07, 19:30] Isro Sumanth: Iske baad

Shaft torque transmitt kr rhi hai srress konsa hoga , maxstress, kaha pe hoga

Fir gear se poochha ki kyu use krte hai, uske baad bola gear ki jagah belt kyu ni krte use

Fir production se tolerence, geometric tolrence, surface roughness, if waviness and surgace roughness are diff.

Fir roughness ko dikhane ke liye kya use krte hai

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36. ISRO – OTHER INTERVIEW QUESTIONS

Date = 1July 2021

Interview was conducted through video conferencing.

Q1. Introduction

Q2. Draw Otto and diesel cycle, now tell us which cycle is more efficient and why ?(told)

Q3. what is entropy and how it is used practically (Told but he seemed to be less satisfied)

Q4. Tell about Second law of TD (Told)

Q5. Draw velocity profile in a pipe flow, why is this profile like it is ? (Told)

Q6. Tell about viscosity and by what law defines it ? (Told and due to laminar term he asked further)

Q7. What’s the difference between laminar and turbulent flow ?

(Told and Reynolds entered 😊)

Q8.What’s Reynolds no. and it’s significance.

(Told but came to the point in the end I.e. ratio of Inertia force and viscous force)

Q9. What is the difference between structure of a CNC and Conventional machine e.g. Lathe?

(Asked due to my Masters, Couldn’t understand question properly but with hint tried to make some points.)

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37. ISRO – OTHER INTERVIEW QUESTIONS

Kolkata 11:00AM to 2:00 PM

Kolkata

11:00AM

Introduce yourself

Favorite subject

SOM

What are various properties of a material

Which property is is used to find stiffness

Straw stress strain diagram of mild steel

Represent the region which represent stiffness

Draw a cantilever beam

Point load at length 2l/3 from fix end

Draw SFD and BMD

Find deflection at point of load and free end.

HT

1 D heat conduction equation in Cartesian coordinates

Draw 2 slab end to end

One is Steel other is Al

One end at T1 other end at T2

Assume T1 >T2

Draw temperature profile

What is contact resistance,why do we get it?

Engineering Graphics

What is difference between 3rd angle and first angle projection.

Draw a square pyramid in 1st angle projection.(drew side view in wrong side),they asked to correct it.

What is difference between orthographic and perspective view.(told but they asked what is basic difference)

Project:

What are different types of grooves(told only know V groove,they were asking more)

Energy density curve for EDM LBM MIG and arc welding.

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38. ISRO – OTHER INTERVIEW QUESTIONS

Isro mechanical interview experience

21/04/21

Briefly introduce yourself

VSSC

Given a set of forces and told to calculate dimensionless numbers

Inertia force

Viscous foce

Gravity force

Surface tension force

Pressure force

Elastic force

Why do we need similitude

Define geometric kinematic and dynamic similarly (examples)

Physical significance of NU PR

peclet no, Stanton no (one more number.. Never heard of it.. Forgot its name. Probably from mass transfer)

The interviewer was kind enough to give me a second chance to correct my answers.. Twice..and he himself pointed out the mistake!

SHAR

Accuracy and precision

How do we classify tolerance

What is tolerance

How do we classify surface roughness

I need a flat surface.. Tell me how will I manufacture it

Surface roughness symbols

What does the triangle stand for? (sorry sir! )

And some more that I forgot..

HQ

How will you find strength of a material

Name the machine

How will you measure stress strain

Why failure occurs

Why cracks develop

Which material to be used in tensile compressive shear load

What is fatigue stress

Creep vs fatigue

Draw stress strain ms ci glass rubber

Name all points on ms stress strain diagram

Why Ms curve is longer

What is yield stress

What is strength

UTS more or yield stress? Why?

Why brittle fail so early

What is gear ratio

Why we have so many gears in cars bikes

How will gear ratio vary when we change from 1st to last gear

Classification of gears

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39. ISRO – OTHER INTERVIEW QUESTIONS

My interview was in Nagpur

I wish all of them good afternoon..then asked me to sit….then they told me introduce yourself…..i introduce…..my schooling graduation and hobbies… Then directly asked what is magnus effect ….then asked me favourite subject…..(Som TOM MS TD HT)….. First question asked about gyroscope

Then where it is applicable in space

What is balancing how balancing is done for v engine

What is finite element method?

How many method is available for FEM?( Ask bcz i had studied in graduation)

How concentricity represent symbol?

Draw stress strain diagram for hard and soft rubber?

How many method used for measuring angular deviation?

Method used for surface roughness?

How we draw plain and diagonal scale and what is the use?

Significance of nussult no. Biot number thermal diffusivity?

Boussinque criteria in heat transfer?

Explain dislocation theory?

What is the phase diagram?

Why iron carbide is equilibrium and TTT is non equilibrium diagram?

Size of spheroid present on nodules cast iron?

Mechanical advantage?

What is the mechanical advantage for screwjack?

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40. ISRO – OTHER INTERVIEW QUESTIONS

1.chairperson (CP1)- Introduce yourself -I have told my schooling ,engg clg name,Btech project,work experience.

2 .CP1-What you did after 2017 -Preparing for competitive exams

3.CP1-Tell me your favorite subjects?-FM,Thermo ,HT,RAC,SOM,Material science.

4.CP1- ohhk materical science and you have written aerodynamics inyour project then tell material which you use in this

5.CP1- (there was a stress strain graph on the board i think drawn by previous student) Can you guess what is this graph for?

Can you name the material ?

Can you draw a true stress strain graph?

Why is this graph like that ?

P2-

Do you know wht is water hammering? As you told your Favorite sub is FM.

Can you just draw the velocity profile for that?

If water flowing in a straight pipe wht will be the maximum mass flow rate can be?-

For the same can you draw graph between mass flow rate and pressure difference?

Wht is surface tension?

Compressible flow depends on wht?

P2-( Related to my project)

– wht are parameters you considered while designing you aerodynamics parts ?

And how you validated your result?

P4-

Wht are the non destructive techniques?.

Tell me different type of gears?

Which type of gears used for perpendicular motion trasnmisssion?

Wht parameters are considered for gear designing?

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41. ISRO – OTHER INTERVIEW QUESTIONS

Interview was conducted online at NRSC Hyderabad .

Me entered into the room and wished good morning.

HR: Good morning Uttej . Take your chair.

Me : Thank you sir.

HR: Tell us about yourself.

Me : Told.

HR : Tell your btech favourite subjects

Me : HT, Thermodynamics, FMHM, SOM, Design.

HR : said other scientist to take over.

Scientist 1 : Did you study mathematics.

Me : yes sir

Scientist 1 : Draw a plane ax+by+cz+d=0

Me : me drawn

Scientist 1 : draw a line in the plane.

Me : drawn.

Scientist 1 : tell the condition for line to be in plane.

Me : doubtfully told a condition.

Scientist 1 : draw a wall and a house facing east with sun at inclination of 30° .

Me : drawn

Scientist 1 : How will you find the inside temperature of the house. Wall of the house is made of three layers and ambient temperature 40°C.

Me : sir i need radiation radiation heat transfer value.

Scientist 1 : Gave some value of incident radiation.

Me : explained.

Scientist 2 : Asked about engineering drawing and asked to draw a rectangle.

Me : Drawn.

Scientist 2 : on which side you will roll the sheet to have higher bending stiffness.

Me : Written bending stiffness equation and explained

Scientist 2 : Develop a conical shell.

Me : Drawn on the board

Scientist 3 : what is transition metal

Me : sorry sir. I didn’t get a opportunity to learn about

Scientist 3 : which welding used to join dissimilar materials.

Me : said friction welding.

Scientist 3 : why dissimilar materials are not joined general welding processes

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42. ISRO – OTHER INTERVIEW QUESTIONS

Asked me to draw Spring mass system diagram on board –

What is its natural frequency?

What about linear frequency?

If I know only deflection?

How you got that equation, do it?

Add damper and write equation?

Show the motion curve of mass?

How should I get damping ratio?

If I want from the curve?

What are materials Used in space?

Where should we use them?

When the discharge is maximum in a pipe flow?

What is cavitation?

Types of manufacturing processes?

What is TIG?

How is TIG different from EBW?

What are steering mechanisms Used in Automobile?

What is working of Ackerman steering?

Nothing was asked from my favorite subjects.

 

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