Physical quantity

Definition

A physical quantity is a property of a material or system that can be quantified by measurement. Examples include length, mass, time, and electric current.

5 Must Know Facts For Your Next Test

1. Physical quantities are divided into two categories: base quantities and derived quantities.
2. The International System of Units (SI) defines seven base units for fundamental physical quantities.
3. Derived units are combinations of the seven base units through mathematical expressions.
4. Each physical quantity has a dimension that indicates its nature in terms of basic physical quantities.
5. Measurement accuracy and precision are critical when dealing with physical quantities.

Review Questions

• What distinguishes a base quantity from a derived quantity?
• How many base units are defined in the International System of Units (SI)?
• Why is it important to consider measurement accuracy and precision in physical quantities?

Related terms

Base Quantity: A fundamental physical quantity from which other quantities are derived, such as length, mass, and time.

Derived Quantity: A physical quantity obtained from the combination of base quantities through mathematical operations.

Dimension: An expression showing how a physical quantity relates to fundamental quantities like length, mass, and time.