⚛️ NPCIL Interview Experience – Mechanical Engineering (GATE 2025)

• Date: 13th June 2025
• Venue: Kaiga, Karwar, Karnataka
• Duration: ~45 minutes
• Mode: Offline, Whiteboard-based Technical Interview

Introduction & Warm-Up

As I entered the interview room, the panel welcomed me warmly and began with light conversation to make me feel comfortable.

They asked:

• “Kahan se aaye ho?” (Where have you come from?)
• “Kaisa raha safar?” (How was your journey?)

They noticed a 6-year gap in my academic record and asked about it.
I honestly explained that I had been involved in farming and preparing for competitive exams during that time.

Subjects of Interest

When asked about my preferred subjects, I mentioned:

• Thermodynamics
• Basic and Applied Thermodynamics (BTD & ATD)
• Fluid Mechanics (FM)
• Heat Transfer (HT)
• Refrigeration and Air Conditioning (RAC)
• Strength of Materials (SOM)

However, based on my farming background, the panel interestingly began with practical mechanical systems used in agriculture.

Interview Questions & Discussion

🌾 Agricultural Machinery and Pumps

1. “Which pump is used in your borewell?”
2. “Why not use an axial flow pump instead?”
3. “Do you own a tractor?”
   • I said no, but they still asked:
     • “Do you know what PTO (Power Take-Off) is?”
     • “How is the PTO shaft connected and used in tractors?”

🚗 IC Engines and Automobile Basics

4. “Have you seen a four-stroke engine?”
5. “What are examples of 2-stroke and 4-stroke engines?”
6. “Have you ever opened a car bonnet? What components did you see?”
   • I mentioned radiator, cooling system, and battery, which led to:
     • “What is the radiator and how does it function?”
     • “How does coolant extract heat from engine parts?”
     • “What parts are cooled and what is the efficiency of a four-stroke engine?”
7. “While riding uphill, which gear should be used and why?”
8. “If we decrease the gear, what happens to torque and speed?”
9. “If the bike is moving at 20 km/h in 2nd gear vs 3rd gear, how will engine RPM differ?”
10. “In uphill conditions, what is more important: torque, speed, or power?”

🔧 Mechanical Components

11. “What are the major components of an IC engine?”
12. “What is a piston? What is mounted on it?”
13. “What are piston rings and why are they used?”

🧊 Heat Transfer in Daily Life (Matka Example)

14. A female panelist asked:

• “Have you seen a matka (earthen pot)?”
• “Why does water stay cool in it? What type of heat transfer occurs?”
• “If a matka is left for a month in a room, will all the water evaporate?”
• “What’s the difference between water in a matka and a glass in terms of heat transfer?”

🔬 Material Science & Metallurgy

15. One panelist asked:

• “Have you studied Material Science recently?”
• I admitted it’s been a while since 2019.
• He continued:
  • “What are your favorite topics in Material Science?”
  • “Draw and explain the Iron-Carbon diagram.”
  • “Differentiate between Cast Iron and Steel.”

🔥 Thermodynamics & Pressure Systems

16. Chairperson asked:

• “If a vessel is heated on an open flame, what happens?”
• “If the vessel is closed, how will that change?”
• “Will the thermometer reading be the same in both cases?”
• “If a vessel is filled fully with water and sealed, what happens when heated?”
• “What will be the saturation temperature if water is pressurized in a sealed vessel?”

🌊 Cavitation & Toughness

17. “What is cavitation? Is it good or bad?”
18. “What materials are used to prevent cavitation or pitting?”
19. “What is toughness? Give examples of tough materials.”

🪑 Observation-Based Questions

20. Looking around the room, the panel asked:

• “Which items around you are made of metal?”
• “What is the composition of those metallic items?”

🌀 Springs in Engineering

21. “What’s the difference between a helical spring and a leaf spring?”
22. “Where do you see each type being used?”
23. “Which spring is used in passenger vs goods locomotives?”

🛠️ Final Year Project

24. They asked:

• “What was your final year project?”
• I replied it was a lawn mower grass cutter, but due to the time gap, I couldn’t recall all the details.
• Still, they insisted and asked:
  • “What was the prime structure?”
  • “What type of blades and wheels were used?”
  • “What type of gears were used?”

🎯 Conclusion

• At the end, the chairperson asked me to clean the whiteboard.
• Then, with a smile, he offered me a chocolate and said:
  “Best of luck!”

✅ Remarks:

• The interview was a blend of technical fundamentals, daily-life application-based questions, and practical observations.
• The panel was friendly yet probing, ensuring they understood my grasp on both theoretical and practical aspects.
• Despite the 6-year gap, they appreciated my honesty and ability to link real-life experience (farming, vehicles, daily tools) to engineering concepts.

Status: Result Awaited