INPhO (Indian National Physics Olympiad) Exam Survival Guide

Window: Analytical + Derivations | Areas: Mechanics, Thermo, E&M, Optics, Modern

Must-do topics

• Mechanics: CM, rotation, constraints, energy methods
• Thermodynamics: cycles, Maxwell relations lite, kinetic theory
• E&M: fields/potentials, circuits (Thevenin), RC/RL/LC transients
• Optics: interference/diffraction setups, lens combinations
• Modern: photoelectric, Compton, atomic models; basics of semiconductors

Top traps (avoid)

• Sign conventions (optics, work, potential)
• Dropping limits/approximations validity
• Algebraic slog without physical reasoning sketch
• Units missing in final results

Study split
45% problems (HCV I/E, Irodov select, past INPhO) | 25% derivations | 20% experiments/estimation | 10% mocks

Last-48h checklist

• 15 mixed problems (one per domain) timed
• Re-derive 5 formulae (e.g., small-angle pendulum, lens maker, RC step)
• Build a constants + approximations card (g, k, ε0, orders of magnitude)

Quick facts/frames

• Start with diagram + assumptions; choose energy vs Newton’s laws consciously
• For circuits: reduce → write KCL/KVL → solve clean matrices
• Optics: draw principal rays; check sign table before algebra

Speed tactics

• Estimate first; sanity-check order of magnitude
• Box intermediate results; keep symbols till last, plug numbers once

Exam-day mini-plan
Sweep for 2 sure problems → anchor 1 long derivation → 2 medium problems → 20 min units/sign audit