Length or Distance:

1
Fundamental Units (SI)

• Length or Distance
• (meter)

the length equal to 1 650 763.73 wavelengths in
vacuum of the radiation corresponding to the
transition between the levels 2p and 5d of the
krypton-86 atom
2
Fundamental Units (SI)

• Mass
• (kilogram)

a cylinder of platinum-iridium alloy maintained
under vacuum conditions by the International
Bureau of Weights and Measures in Paris
3
Fundamental Units (SI)
the duration of 9,192,631,770 periods of the
radiation corresponding to the transition between
the two hyperfine levels of the ground state of
the cesium-113 atom

• Time
• (second)

4
Fundamental Units (SI)

• Electric
• Current
• (ampere)
• Temperature
• (kelvin)

that constant current which, if maintained in
two straight parallel conductors of infinite
length, of negligible circular cross section, and
placed one meter apart in a vacuum, would produce
between these conductors a force equal to 2.E-07
newtons per meter of length
based on six fixed points
5
Fundamental Units (SI)

• AMOUNT OF SUBSTANCE (mole)

the amount of a substance which contains as many
elementary entities as there are atoms in 0.012
kilograms of Carbon 12
6
Fundamental Units (SI)

• LIGHT OR LUMINOUS
• INTENSITY(candela)

the luminous intensity, in the perpendicular
direction, of a surface of 1/600,000 square
meters of a blackbody at the temperature of
freezing platinum under a pressure of 101,325
Newtons per square meter
7
Supplementary Units (SI)

• PLANE ANGLE
• (radian)

the plane angle between two radii of a circle
which cut off on the circumference an arc equal
in length to the radius
8
Supplementary Units (SI)

• SOLID ANGLE

the solid angle which, having its vertex in the
center of a sphere, (steradian) cuts off an area
of the surface of the sphere equal to that of a
square with sides of length equal to the radius
of the sphere