Chapter 2 · ICSE Class 6 Physics (Selina Concise)

Physical Quantities and Measurement

Learn about fundamental physical quantities, their SI units, and how to measure length, mass, and time accurately.

📏 Chapter 2

A table of physical quantities and their SI units A table listing three physical quantities: length measured in metres, mass measured in kilograms, and time measured in seconds Quantity SI Unit Length metre (m) Mass kilogram (kg) Time second (s)
2.1

Fundamental Physical Quantities

Length, mass, and time are fundamental quantities with SI units: metre (m), kilogram (kg), and second (s) respectively.

1

What is the SI unit of length?

Metre (m)

2

What is the SI unit of mass?

Kilogram (kg)

2.2

Measuring Instruments

Different instruments measure different quantities: a metre scale measures length, a beam balance measures mass, and a stopwatch measures time.

1

Which instrument would you use to measure the mass of a book?

A beam balance or a weighing scale

2

Why is a measuring tape better than a metre scale for measuring the circumference of a tree?

A measuring tape is flexible and can bend around curved surfaces, unlike a rigid metre scale

Practice

Exercises

1. What is the SI unit of time?

2. Name an instrument used to measure length.

3. Convert 5 kilometres into metres.

4. Convert 2,500 grams into kilograms.

5. Which instrument measures mass — a stopwatch or a beam balance?

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