Chapter One: Units and Measurement

These flashcards include key vocabulary terms and definitions related to units and measurement, emphasizing important concepts such as significant figures, dimensional analysis, and the international system of units.

Unit

A basic, arbitrarily chosen, internationally accepted reference standard for measuring physical quantities.

Fundamental Units

The base units for fundamental or base quantities.

Derived Units

Units that can be expressed as combinations of fundamental units.

International System of Units (SI)

A globally accepted system of measurement that uses seven base units.

Significant Figures

Digits in a measurement that are known reliably plus the first uncertain digit.

Dimensional Formula

An expression that shows how and which of the base quantities represent the dimensions of a physical quantity.

Radian

The unit of plane angle defined as the ratio of the length of an arc to its radius.

Steradian

The unit of solid angle defined as the ratio of the intercepted area of a spherical surface to the square of its radius.

Dimensional Analysis

A method to check the dimensional consistency of equations and deduce relations among physical quantities.

Base Quantities

Fundamental quantities such as length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity.

System of Units

A complete set of units, including both fundamental and derived units.

SI Base Units

The seven internationally standardized units for measuring base quantities.

Precision of Measurement

A description of how close the measurements are to each other, indicating the quality of measurement.

Homogeneity of Dimensions

The principle stating that physical quantities can only be added or subtracted if they have the same dimensions.

Scientific Notation

A way of expressing numbers as a product of a number between 1 and 10 and a power of 10.

Order of Magnitude

The power of ten when a quantity is expressed in scientific notation.

Errors in Measurement

Uncertainties in measurement that affect the reported values, often quantified in terms of significant figures.

Exponential Notation

A way of expressing numbers in the form a × 10^b, where 'a' is a number between 1 and 10, and 'b' is the exponent.

Theorem of Dimensional Consistency

The concept stating a dimensionally correct equation need not be correct, while a dimensionally wrong equation must be wrong.