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

4 pages178 viewsFall 2015

Department

Basic EngineeringCourse Code

BE 1101Professor

AllChapter

PermachartThis

**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 ¥10–7of 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

1 cm2 = 0.1655 in2

1 dm2 = 100 cm2 = 0.01 m2

• 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

###### You're Reading a Preview

Unlock to view full version

#### Loved by over 2.2 million students

Over 90% improved by at least one letter grade.