BARC Interview Experience (Instrumentation) 2019
What is BARC?
Bhabha Atomic Research Centre (BARC) is India’s premier nuclear research facility, headquartered in Mumbai, Maharashtra. It is a research center with extensive infrastructure for advanced research & development.
How I Got Selected in BARC Interview?
I am a 2016 pass out with no job no experience…no coaching no notes…only books and Facebook Group GATE Aspirants
I Started preparing for BARC in 2017 June.
I got failed in Gate 2018 (rank 480 no use in my branch) and the BARC Interview 2018.
Result— I got selected
I was selected for the interview based on my performance in online examination (GATE rank-186)
My interview was on 29 May. I reached the Interview venue in the morning and waited all day for the Interview.
My interview started at around 5:10 PM.
BARC Interview Questions
Here is the list of interview questions that were asked from me in the BARC Interview
First, they asked me whether I have had my lunch and then they asked where am I from and a little bit about my name and some family related stuff.
Then they asked me about my favorite subjects, to which I responded:
1. Analog Electronics
2. Control Systems
4. Digital & Multiprocessor
5. Process Control
Since I am from Instrumentation they started with Process Control
Q) Draw the block diagram of an automatic control system
Q) Explain all the things in the block diagram
Q) Can a Negative Feedback System be unstable
A) I answered yes it can be unstable.
Q) Draw positive feedback block diagram and the basic difference between negative and positive feedback.
A) Told him the loop gain is 1 for positive and -1 for negative so it’s basically a phase difference.
Q) What if the loop gain of the negative feedback system is -1?
A) I told him system will be unstable…he also told me that negative feedback is always stable and became unstable only when parameters change forces it to become positive feedback system (Maine bola bat to wahi hui sir he said no😬😬)
Q) Draw a temperature control system. I was about to draw the system but he said give me the paper and he gave me a diagram of the heat exchanger and asked me how will u control it which type of control action?
A) I said feedback.
Q) Ok, then draw the block diagram of the system. He also asked me what will be your process, what will be in the feedback path and all.
A) I gave the answers correctly.
Q) Now he asked me where will I show disturbances in block diagram
A) I gave the answer.
Q) Ok now tell me the disturbance (load in process control terminology) in heat exchanger system
A) Told them 4 to 5 loads but he was asking aur batao aur batao kya load hoga. I told him heat loss from the heat exchanger surface..now from his facial expression I knew he was waiting for this answer only.
Q) n3..ow which controller will you use?
Q) Why PID why not P or PI?
A) Told them that the temperature system is slow so to get fast response Derivative is necessary.
Q) Asked advantage and disadvantages of derivative controller & in which control system derivative is prohibited?
A) Flow Generally
Q) What will be the output of the PID controller to step input? Draw the total response of the system with PID controller in action? Why PID controller output is different from the total response curve?
A) I was stuck here but they gave me a little hint and I got the answer correctly.
Q) Which flow meter will you use for bi-directional flow?
A) Told them orifice but he said no you can’t use orifice flow meter. I told him why not I can use because it is symmetrical for upstream and downstream flow..but still he said no
Q) Then asked me to draw the cross-sectional diagram of the orifice.
A) I drew a diagram given in the book but he said no this is for representation, not cross-sectional diagram..told him I don’t know them
Q) Again asked me to tell me other bidirectional flow meters think think
A) I told him magnetic flow meter..he said yes u can …
Q) Now draw the neat and clean diagram of this flowmeter
A) I told him I don’t know..them he asked which magnet electro or permanent magnet..how will you install electrodes in a pipe and other design specific. I was saying “I don’t know” for at least 3 to 4 questions back to back…
Now he came to temperature measuring devices.
Q) What is the temperature??
A) Told him
Q) What is specific heat??
A) Told him.
Q) Then they asked me can water be in the liquid and gaseous state at the same temperature
A) I told him don’t know then he said what is latent heat told him ..and repeated the previous question and I said yes water can.
Then asked about thermocouple all basics..asked me how to connect voltmeter..changes wires and all and asked everything told them..now they gave me a problem numerical and asked to solve orally. I told him I can solve it on paper but not orally ..he said no do it. I told him I can’t ..ok solve on paper solved correctly.
Q) How will u install thermocouple in the pipe with steam flowing
A) I literally said sir bus aise laga denge (I drew it on the paper) he said u mean u will drill the pipe. I said yes ..they all started laughing..then asked me you will install perpendicular or at angle?? I said no idea, sir.
Q) Then he drew a diagram and told me what is the difference of response of the two thermocouples??
A) I told him angled one will respond faster than perpendicular one..asked me why told him due to surface area…he said ok.
Q) Then asked how thermocouple are protected from environmental effects…
A) Told him will use insulator since thermocouples are nothing but two wires.
Asked me to derive the transfer function of thermocouple with insulator..meri halat khrab bc ye kya pooch liya…he said u r prepaing from three years and u dont know this? I said no sir.
Q) Now they returned to PID controller & asked how will you tune? Tell us the best method…
Q) Explain Ziegler Nicholas method thoroughly some cross question answerable.
Then he said the system will not work properly even if u tune with Ziegler Nicholas method… I said maine book me yhi padha hai sir…
Then he said tumne fine tuning ka name suna hai I said no…
Ok last question kis subject se pooche?
I said analog but they asked from network ..phasor diagram and kcl combined.. I was struck but they gave me hint to solve and I solved correctly…they made a joke…tume kcl bhi ni aata kya padhai kiye ho😀..
In between they offer me fanta🤣🤣…jo mere gale me niche ni ja rhi thi..
This was all about my BARC interview experience.
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