Core5 mapped NDA questions
Build the idea
Build exam-ready understanding by connecting the core idea, formulas or facts, worked example and previous NDA questions. Focus on why each rule works, then test it under timed conditions.
Concept
The NDA syllabus lists everyday devices whose basic working principle may be asked: simple pendulum, pulleys, siphon, levers, barometer, pressure cooker, thermos flask, periscope, telescope and others.
Each relies on one core physics idea — identify it.
Key Points & Formulas
- Pressure cooker: raises boiling point by increasing pressure, cooking faster.
- Thermos flask: a vacuum and silvered walls minimise conduction, convection and radiation.
- Periscope: uses two plane mirrors (or prisms) at 45°.
- Siphon: atmospheric pressure and gravity move liquid over a barrier.
Worked Example
Q. Why does food cook faster in a pressure cooker?
Trapped steam raises the pressure inside.
Higher pressure raises the boiling point of water above 100 °C.
The hotter water/steam cooks food faster.