Technical Interview Questions

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CSE

What is the difference between a process and a thread?

A process is like an independent house with its own resources (memory, kitchen, bathroom). A thread is like a family member living in that house, sharing the common resources but having their own tasks.

Updated 20265 min read

CSE

Explain OOPs concepts with real-world examples

OOPs is like organizing a company: Encapsulation (departments keep their data private), Inheritance (junior roles inherit from senior roles), Polymorphism (same job title, different work in different departments), Abstraction (CEO sees high-level reports, not every detail).

Updated 20265 min read

ECE

Explain the working of a PN junction diode

A PN junction diode is like a one-way door for current. When you push from the P-side (forward bias), the door opens and current flows. When you push from the N-side (reverse bias), the door stays closed. The "doorframe" is the depletion region that controls this behavior.

Updated 20265 min read

ECE

What is the difference between analog and digital communication?

Analog communication is like a live concert—sound waves travel continuously as they are. Digital communication is like sending a text message—the voice is converted to 0s and 1s, sent, then reconstructed. Digital is like sending LEGO instructions instead of the actual sculpture—easier to fix if pieces are missing.

Updated 20265 min read

Explain Kirchhoff's laws with examples

KCL (Current Law): At any junction, what goes in must come out—like cars at an intersection. KVL (Voltage Law): Around any closed loop, the total voltage rise equals total voltage drop—like climbing a hill and coming back down, net elevation change is zero.

Updated 20265 min read

What is the difference between AC and DC?

DC is like a steady river flowing in one direction—constant and predictable. AC is like ocean waves—current flows back and forth, changing direction 50-60 times per second. Your home uses AC (from power plant), your phone charges on DC (battery).

Updated 20265 min read

Explain the four strokes of an IC engine

A four-stroke engine works like breathing deeply: (1) Inhale = Suction stroke (take in air-fuel), (2) Hold breath = Compression stroke (squeeze the mixture), (3) Cough = Power stroke (spark ignites, pushes piston), (4) Exhale = Exhaust stroke (push out burnt gases). One complete cycle = 2 crankshaft rotations = 720°.

Updated 20265 min read

What is the difference between stress and strain?

Stress is the "cause" (force applied), strain is the "effect" (deformation produced). If you pull a rubber band, stress is how hard you pull (force per area), strain is how much it stretches (change in length divided by original length). Stress has units (N/m² or Pascal), strain is dimensionless (ratio).

Updated 20265 min read

Civil

What is the difference between one-way and two-way slab?

Imagine carrying a rectangular tray: If it's very long and narrow (like a ruler), it bends mainly along the length—that's one-way slab behavior. If it's nearly square, it bends in both directions equally—that's two-way slab behavior. The aspect ratio (Ly/Lx) determines which type it is.

Updated 20265 min read

Civil

Explain grades of concrete and their uses

Concrete grades like M20, M25, M30 indicate strength. "M" stands for Mix, and the number is the characteristic compressive strength in MPa (N/mm²) after 28 days. Higher the number, stronger the concrete. M20 for regular buildings, M40+ for bridges and high-rises.

Updated 20265 min read

ChemE

What is a unit operation? Give examples

Unit operations are physical changes that don't alter the chemical nature of substances—like sorting, mixing, heating, filtering. Think of cooking: chopping vegetables (size reduction), boiling water (heat transfer), straining pasta (filtration) are all unit operations. No new substance is created, just physical transformations.

Updated 20265 min read

ChemE

Explain mass transfer operations with examples

Mass transfer operations separate mixtures by moving components from one phase to another. Think of making tea: flavor compounds transfer from tea leaves (solid) to hot water (liquid). Distillation, absorption, extraction, drying—all involve mass moving between phases driven by concentration differences.

Updated 20265 min read

What is the difference between SQL and NoSQL databases?

SQL databases are like Excel spreadsheets—organized tables with rows and columns, strict structure. NoSQL databases are like folders with documents—flexible, each document can have different fields. SQL = predictable structure, strong relationships. NoSQL = flexibility, horizontal scaling.

Updated 20265 min read

Explain the OSI model layers

OSI model is like sending a letter: You write content (Application), put it in envelope (Presentation), address it (Session), choose courier (Transport), courier plans route (Network), puts in delivery van (Data Link), van drives on road (Physical). Each layer adds its own "wrapping" going down, removes it going up.

Updated 20265 min read

Biotech

What is PCR? Explain its applications

PCR is like a molecular photocopier for DNA. Starting with one DNA strand, it makes millions of identical copies in just a few hours. It works by repeatedly heating and cooling the sample with special ingredients, doubling the DNA each cycle. 30 cycles = 2³⁰ = 1 billion copies!

Updated 20265 min read

Biotech

What is fermentation? Explain its types and applications

Fermentation is like controlled farming of microorganisms. You provide them food (substrate), comfortable conditions (temperature, pH), and they produce useful products (antibiotics, alcohol, enzymes). Like curd from milk—bacteria convert lactose to lactic acid. Industrial fermentation does this at massive scales in bioreactors.

Updated 20265 min read

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