# BARC Interview Questions For Mechanical Students

Bhaba Atomic Research Center Scientific Officer (BARC) OCES DGFS interview cracking tips with the aspirants, These are the general tips for each candidate preparing for BARC interview (all branches). In order to avail branch specific tips, candidates must themselves focus on the basic concepts of each subject prepared for the interview. If you are good with your concepts, nothing would hinder your aim to reach BARC as a Scientific Officer.

Highlights of BARC Interview

• BARC interview is one of the best interviews a candidate would face which seems more of a one to one discussion with each panel member.
• The interviewers or the Scientists of BARC have an amazing approach of judging the abilities of a student where they will give you ample time and hints to think and reply to a question.
• If you provide the right answer to a question, the next one will heavily be dependent on the answer. That’s the pattern to test your knowledge.
• The panel tests your approach towards a problem. Hence try to give the answer to every possible question and avoid saying “I DON’T KNOW” directly.
• They ask the subjects of your interest and questions will be directed from those subjects.
• Every interviewer is polite and does not humiliates you even if you make a blunder. So, avoid any sort of hesitation while answering the questions
• So it is suggested to just enjoy the interview session as the time will pass by so quickly that you won’t even realize.

Ashish Shrivas has shared his experience of interview  :

Interview panel is a group of 6- 7 persons

At the beginning they told me to write 4 subjects.

I wrote

Heat transfer
Thermodynamics
Fluid mechanics
Mechanics of solid

The chairman started with fluid mechanics.

He draw a tank and at the bottom he made an opening.

Q1- What will be velocity.
Me- √2gh

Q2- Now he attached a nozzle and ask what will be change in velocity.
Me- velocity will increase.

Q3- Variation in pressure.
Me- pressure will decrease.

Q4-Now he attached a diffuser, and now variation in velocity.
Me- velocity will decrease.

Q5- variation in pressure.
Me- pressure will increase.

Q6- Than how flow is possible from low pressure to high pressure.
Me- Tried to explain by Bernoulli’s theorem, but he was not satisfied.

Q6- what is Archimedes principle.
Me- buoyancy is equal to weight of fluid displaced.

He draw a trapezoid(iron) at the bottom of the tank and drew two forces on top and bottom surface.

Q7- which force will be large.
Me- force=wha, so force will depend on both area and depth of surface.

Q8- Will difference of force will equal to buoyancy.
Me- No, buoyancy will equal to weight of fluid displaced.

Q9- Why?
Me- It is case of hydraulic paradox, hydraulic force will act on side faces also.

Then other person started with Heat transfer.

He draw two stab connected end to end of same dimensions one with thermal conductivity k and other with k/2.

Q10- Draw temperature vs length variation diagram.
Me- Drawn.

Q11- Which law is used to explain this.
Me- Fourier law of conduction.

Q12- why is their is change in slope and how much.
Me- Explained.

Q13- Now their is atmosphere temp. T and thermal coefficient h. Calculate T1( first surface) T2(intermediate temperature) T3(End surface).
Me- Derive 3 equation by Fourier law, said i have 3 equations and 3 unknown so i can easily calculate.

Q14- Now i double the heat flux, what will be change in temperature variation.
Me- Drawn

Q15-What will be relation between 1st and 2nd condition slope.
Me- second will be 2 times first.

Q16-How will temperature vary between slab and atmosphere.
Me-Drawn

He draw a open beaker containing water on a furnace.

Q17- Draw temperature vs time variation diagram.
Me- Drawn

Q18-Now the specific heat ‘c’ changes with temperature.
Me- Drawn (it will be parabolic with decreasing slope)

Q19-Why this curve, and why decreasing slope.
Me-Because as temperature increases c increase so the heat storing capacity increases therefore initially temperature rise rate will be fast and rate will decrease with increasing temperature.

Q20- How boiling time will change, when we take it to the top of hill.
Me- Thinking.

Q21- Chairman asked how latent heat varies with pressure.
Me- It increases with decreasing pressure.

Q22-Than will it take more time to boil?
Me-With decrease in pressure saturation temperature also decreases so it will take less time to reach the boiling temperature but with decrease in pressure latent heat increases so the phase change will be longer.

Q23- Draw volume vs time diagram for water.
Me- Drawn and at 100℃ make a Sharpe increase in volume.

Q24- Why you have made a Sharpe increase in volume.
Me- Because at 100℃ phase change occurs and specific volume of steam is very large than water.

Q25- Chairman said but we told you to draw for water not steam.
Me-corrected and drew a downward sloping linear line from 100℃.

Q26- Chairman why you have made this curve.
Me- At phase change q.t=m.LT(latent heat) so the evaporating mass is linearly proportional to time so is the remaining mass.

Then 3rd person started to ask from thermodynamics.

Q27- What is Boyle’s law.
Me- silent

He- What hapended?
Me- Sir i forgot, i am confused between constant temperature or pressure.

He- Constant temperature.
Me- At constant temperature pressure is inversely proportional to temperature.

Q28- what is Charles law.
Me- At constant pressure, volume is directly proportional to temperature.

Q29-Chairman in middle asked according to Boyle’s law pv=c, than why when inflating balloon pressure and volume both increase?

Me-Because while inflating we are adding mass and Boyle’s law is applicable to constant mass system.

Q30-Than how mass is related to pressure and volume.
Me- By ideal gas equation pv=NRT

Other person draw a Tyre and said assume it have initial condition p,v,t after a long drive the pressure in increased to some p1.

Q31-Then how much mass should i remove so that the pressure is becomes to p.
Me- calculate the relation.

Then 4th person started to ask mechanics of solid.

Make a iron pillar.

Q32-Draw stress vs length diagram.
Me- Drawn.

Q33- Chairman asked what will be variation in stress at 12 night and 12 afternoon.
Me-As it is unrestricted expansion so their will be no thermal expansion and length will increase at 12 afternoon but accordingly density will decrease as the mass should remain same so their will be no change in stress.

Q34- Chairman what is density of iron.
Me- around 7800kg/m3

Q35- What will happen if we keep on increasing the length.
Me- Failure due to crushing.

Q36-Chairman but practically failure occurs prior to crushing.
Me- because of buckling.

Q37-How buckling load is given.
Me- Euler’s formula.

Q38-For this case what is effective length.
Me- 2l

Q39- Draw the deflected diagram.
Me- Asked deflection by self weight
He- yes
Me- Drawn

Q40-Draw deflection vs length diagram.
Me- Drawn(parabolic)

Q41- Why you have draw parabolic.
Me- Derived relation.

Q42- Why this slope.

Me – Explained.

Then the 5th person started to asked from Engineering mechanics.

He draw a tank and make two holes on it one at bottom other on middle.

Q42- Draw trajectory.
Q43- Distances where they will strike ground x-axis.
Q44-Point of intersection of both jets.

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