Short Answer
First postulate is the best answer.
Quantum questions reward precision with language. Identify whether the prompt is about wave behaviour, measurement, states, operators, or quantised energy levels before choosing a formula or interpretation.
The first postulate of QM: a pure quantum state is fully described by a normalised wavefunction ψ in Hilbert space.
Why This Answer Is Correct
This is a Medium-level question in Quantum Physics. The prompt is really testing whether you can connect the concept to its defining physical relationship instead of picking a nearby-but-wrong term.
When a quantum question feels ambiguous, translating it into state, observable, probability, and evolution language usually clarifies the answer.
Choices At A Glance
- A. First postulate
- B. Correspondence principle
- C. Superposition principle
- D. Born rule
When similar options appear on an exam, eliminate the ones that break the core law, use the wrong units, or confuse a definition with a consequence.
Topic Snapshot
Topic: Quantum Physics
Difficulty: Medium
Best next move: Re-state the governing law in your own words, then solve one more example from the same topic before moving on.