Units and Measurements Flashcards

Vocabulary flashcards based on lecture notes about units and measurements, focusing on SI units, derived units, and fundamental quantities.

SI Units

The International System of Units, used for accurately measuring physical quantities.

Fundamental Quantity

A quantity that cannot be expressed in terms of other quantities (e.g., Length, Mass, Time).

Derived Quantity

A quantity which can be expressed in terms of fundamental quantities.

Base Unit

The units of fundamental physical quantities (e.g., metre, kilogram, second).

Length (SI Unit)

Metre (m)

Mass (SI Unit)

Kilogram (kg)

Time (SI Unit)

Second (s)

Electric Current (SI Unit)

Ampere (A)

Temperature (SI Unit)

Kelvin (K)

Luminous Intensity (SI Unit)

Candela (cd)

Amount of Substance (SI Unit)

Mole (mol)

Plane Angle (SI Unit)

Radian (rad)

Solid Angle (SI Unit)

Steradian (sr)

Radian

The SI unit of a plane angle, formed between two lines in a 2D plane.

Steradian

The SI unit of a solid angle, subtended at a point in space by a surface area on a sphere.

Arc Length

The distance along a curved line forming part of a circle.

Radius

The distance from the center of a circle to any point on its circumference.

Surface Area

The total area of the surface of a three-dimensional object.

System of Units

A set of units used to measure physical quantities (e.g., F.P.S., C.G.S., M.K.S.).

F.P.S. System

Foot, Pound, Second system of units.

C.G.S. System

Centimetre, Gram, Second system of units.

M.K.S. System

Metre, Kilogram, Second system of units.

Astronomical Unit (AU)

The average distance between the Earth and the sun (1 AU = 1.496 X 10^11 m).

Light Year (ly)

The distance travelled by light in vacuum in one year (1 ly = 9.46 X 10^15 m).

Parsec

The distance at which an arc of length of one astronomical unit subtends an angle of one second (1 parsec = 3.08 X 10^16 m).

Coherent Unit System

A system where the derived units are obtained by multiplying or dividing base units without introducing numerical factors.

Physical Quantity

Quantities involved in a physical process, which can be measured directly or indirectly.

SI Unit Advantage: International Acceptance

SI units are globally recognized, facilitating communication and collaboration in science and engineering.

SI Unit Advantage: Rational System

The SI system uses only one unit for one physical quantity.

SI Unit Advantage: Metric System

The SI system is based on powers of 10, making conversions simpler.