Paper II · Part B — Physics

Units, Measurement and States of Matter

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Core5 mapped NDA questions

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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

Physical quantities are measured in units; the SI system defines seven base units. Matter exists mainly as solid, liquid and gas, distinguished by how tightly its particles are held.

Knowing the correct SI unit of each quantity is frequently tested.

Key Points & Formulas

SI base units: metre (length), kilogram (mass), second (time), ampere (current), kelvin (temperature).
Derived units: force → newton, energy → joule, power → watt, pressure → pascal.
Solids have fixed shape & volume; liquids fixed volume only; gases neither.
Density = mass/volume (kg/m³).

Worked Example

Q. State the SI units of force, work and power.

Force = newton (N = kg·m/s²).

Work/energy = joule (J = N·m).

Power = watt (W = J/s).

Common traps

Reading the prompt too quickly and missing a qualifier.
Memorising the result without checking when it applies.
Skipping units, signs, chronology or the final reasonableness check.

NDA shortcuts

State the governing rule before substituting values.
Eliminate impossible options before doing full calculation.

One-screen revision sheet

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Core definition
Most-used rule
One representative example

Past-paper bank

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5 NDA questions

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Question 1

NDA II 2025

The energy, $E$ , of a photon can be expressed as $E = hf$ where $f$ is the frequency and $h$ is Planck's constant. The dimensions of $h$ are the same as that of

Question 2

NDA II 2022

The commercial unit of electrical energy is kilowatt-hour (kWh), which is equal to

Question 3

NDA II 2021

The unit of the ratio between thrust and impulse is same as that of

Question 4

NDA I 2021

Which one of the following cannot be the unit of frequency of a sound wave?

Question 5

NDA I 2021

Consider the following statements about Light year :
1. Light year is a unit for measurement of very large distances.
2. Light year is a unit for measurement of very large time intervals.
3. Light year is a unit for measurement of intensity of light.
Which of the statements given above is/are correct?

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