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Reference Guide

Permachart - Marketing Reference Guide: Steradian, Luminous Intensity, Si Base Unit

4 pages178 viewsFall 2015

Department
Basic Engineering
Course Code
BE 1101
Professor
All
Chapter
Permachart

This preview shows page 1. to view the full 4 pages of the document.
Metric System
Metric System
INT R ODU C TIO N SU PPL E MEN TARY U N IT S
LEN G TH ( m)
The International System of Units (SI) is a
modern version of the metric system
• As a result of a long series of international
discussions, on the 14th of October, 1960,
the Eleventh General Conference on Weights
and Measures agreed to adopt the symbol SI
(Le Systéme International d’Unités) to
describe system of measurements consisting
of seven basic units, two supplementary
units, and numerous derived units
• These units appear on this chart along with
their definitions
• Multiples and submultiples are expressed in
the decimal system
• SI has only one unit for any physical quantity
and therefore no conversion factors or
constants need to be remembered
• Radian and steradian are often listed as
supplementary units; the current international
agreement puts these two dimensionless units
into the derived unit category
• The radian (rad) is the plane angle formed
between 2 radii of a circle subtended by an arc
whose length is equal to radius; there are 2p
rad in a circle
• The steradian (sr) is the solid angle at the
center of a sphere which subtends an area on
the sphere’s surface which is equal to the
square of its radius; there are 4psr in a sphere
• The SI system still permits the use
of degrees (deg,°), where 1 circle = 360°
• The use of minutes and seconds is
discouraged; decimal divisions of a degree
should be used
THE RADIAN (rad)
THE STERADIAN (sr)
surface area
= 1 r2
1 rad
2 rad
3 rad
solid angle
1 sr
1 rad
π rad
π = 3.1416
• The SI unit of length is the meter (m)
• Originally, it was 1 ¥107of the
longitude passing through Paris from the
equator to the North Pole
123456789
10
1 2 3 4 5 6 7 8 9
20
123456789
30
12 3 4 5 6 7 8 910111213 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
123456789
40
123456789
50
1 2 3 4 5 6 7 8 9
60
1 2 3 4 5 6 7 8 9
70
1 2 3 4 5 6 7 8 9
80
123456789
90
1 2 3 4 5 6 7 8 9
100
1 millimeter (mm)
1000 mm = 1 m
1 centimeter (cm)
1cm = 10 mm
100 cm = 1 m
1 decimeter (dm)
1dm = 10 cm
1 dm = 100 mm
10 dm = 1 m
1 foot = 30.48 cm
1 yard = 3 ft = 0.9144 m
1 m = 3.2808 ft = 39.3701 in
METER
YARD
KRYPTON 86
(LAMP)
1 650 763.73 wavelengths
1 meter
* Orange-red line of the spectrum of Kr-86
2p10 to 5d5 transition*
• The most commonly
used derivatives of the
meter are area (m2)
and volume (m3)
• The diagrams show
how m, m2, and m3,
as well as their
multiples and sub -
multiples, relate to
objects in everyday life
1 m
Long Step
1 dm
Hand Width
1 cm
Smallest Finger
(Nail Width)
1 mm
Dime Thickness
A
1 m2
Desk Top
1 dm2
Palm
1 cm2
Nail on
Smallest Finger
1 mm2
Thumbtack
Hole
MILK
1 m3
Trunk of
Station Wagon
1 dm3
Quart of Milk
1 cm3
( )
1 cm3
Baby Spoon
1 mm3
Pin Head
1 cm3 = 0.061 in3
1 dm3 (liter) = 1000 cm3 = 0.001 m3
• The standard meter is currently defined as the length of 1,650,763.73 wavelengths (in a vacuum)
of radiation corresponding to the unperturbed transition between the energy levels 2p10 and 5d5
of the Krypton-86 atom
• The wavelength of this orange-red line is 6.057 802 ¥10–7 m
LENGTH (M)
VOLUME (M3)AREA (M2)
1METRIC SYSTEM 1-55080-859-1
l e a r n r e f e r e n c e r e v i e w
TM
permacharts
© 1996-2013 Mindsource Technologies Inc.
w w w . p e r m a c h a r t s . c o m
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