Units and Measurement Lecture Notes

Practice vocabulary flashcards based on the lecture transcript regarding physical quantities, units of measurement, and the SI system.

Physical quantities

The quantities which can be measured accurately.

Fundamental quantities

The physical quantities which are measured independently, such as Mass, length, and time.

Derived quantities

The physical quantities which are derived from fundamental quantities, including area, volume, force, and pressure.

Measurement

The process of comparing a given quantity with a standard amount of the physical quantity of the same kind, called its unit.

Measure of a physical quantity (formula)

$$\text{(numerical value of the physical quantity)} \times \text{(size of the unit)}$$

Physical unit

The standard amount of a physical quantity chosen to measure the physical quantity of the same kind.

Fundamental or base units

Units that are independent of each other, for example, Metre, kilogram, and second.

Derived units

All the physical units obtained from fundamental units, such as Area $\rightarrow m^2$ and acceleration $m/s^2$.

System of units

A complete set of units used to measure all kinds of fundamental and derived quantities.

CGS system

A system based on centimetre, gram, and second as the fundamental units of length, mass, and time respectively.

FPS system

A system based on foot, pound, and second as the fundamental units of length, mass, and time respectively.

MKS system

A system based on metre, kilogram, and second as the fundamental units of length, mass, and time respectively.

SI system

The abbreviation for "System International of units," which is a modernized and extended form of metric systems like CGS and MKS.

Metre ($M$)

The SI basic unit for the fundamental quantity of Length.

kilogram ($Kg$)

The SI basic unit for the fundamental quantity of Mass.

Second ($S$)

The SI basic unit for the fundamental quantity of Time.

Kelvin ($K$)

The SI basic unit for the fundamental quantity of Temperature.

ampere ($A$)

The SI basic unit for the fundamental quantity of Electric current.

candela ($Cd$)

The SI basic unit for the fundamental quantity of Luminous Intensity.

Mole ($Mol$)

The SI basic unit for the fundamental quantity of Quantity of matter.

radian ($Rad$)

The SI basic unit for the supplementary quantity of Plane angle.

steradian ($Sr$)

The SI basic unit for the supplementary quantity of Solid angle.