Legal Metrology Department

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International System of Units

If people of every region use a different unit for weighing, the trade between these two regions will create problems. Now a days inter continental trade is common and the use of a common unit in measurement become essential.

SI (System International) presctibe the unit and it's symbol for international use.

Lenth, mass, time, temperature, volume etc are considered to be basic quantities. The standard unit for the measurement with it's symbol in bracket are

Length : metre (m)
Mass : gram (g)
Time : second (s)
Temperature : kelvin (K) also degree celcius (°C)
Volume : litre (l)

Units are always written singular. There is not dot after the unit symbol. One character space is provided between numeral and unit or it's symbol. Unit with the name of a scientist is always written in lowercase, while the symbol will be in Uppercase.

Eg :

Force : newton (N)
Energy : joule (J)
Power : watt (W)
Voltage : volt (V)
Current : ampere (A)

Prefixes permitted to use with standard symbols are

c - centi (10 ^-2)
m - milli (10 ^-3)
k - kilo (10 ^3)
M - mega (10 ^6)

Prefixes are helpful to write large and small measurements convienently.

Eg :

1,000 m = 1 km
1,000 ml = 1 l
11,000 V = 11 kV
1,000 mg = 1 g
1, 000 kg= 1 t (t, symbol for ton)

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Conversion table

In the earlier days, there were a number of units were used for weighing and measurement in various countries. Later, due to the growth of inter continental trade, a common unit become necessary for the trade.

The following table can be used for unit conversion.

Length

1 mile = 1760 yard
1 mile = 8 furlong
1 furlong = 10 chain
1 chain = 4 rod
1 rod = 5 1/2 yard
1 yard = 3 feet
1 foot = 12 inch

Standard Unit : metre

Area

1 sq. mile = 640 acre
1 acre = 4840 sq. yard
1 sq. yard = 9 sq. feet
1 sq. foot = 144 sq. inch

Standard Unit : metre^2 (sq m)

1 are = 2.47 cents

Volume

1 gal = 4 quart
1 quart = 2 pint
1 pint = 4 gill
1 pint = 34.6774 inch3
1 gill = 5 fl. oz
1 fl. oz = 8 fl. drachm
1 US gal = 0.8327 gal
1 US pint = 0.8327 pint
1 US pint = 16 fl. oz
1 yard3 = 27 feet3
1 foot3 = 1728 inch3

Standard Unit : metre^3 (cub. m)

Weight

1 ton = 20 cwt
1 ton = 2240 lb
1 ton = 1.12 US ton
1 cwt = 4 quarter
1 quarter = 2 stone
1 stone = 14 lb
1 lb = 16 oz
1 oz = 16 dram
1 oz = 437.5 grain
1 US ton = 2000 lb
1 Sovereign = 8 g

Cast Iron weights



Sovereign is a British gold coin (22 carat) with a gold content of 7.322 g (113 grains) weighing 7.9881 g. The coin has a thickness of 1.52 mm and a diameter of 22.05 mm. The coin has an effigy of St George.

Standard Unit : gram
conveniently kilogram and ton are used.

Brass weights

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Length

1 km = 10 hm
1 km = 1000 m
1 hm = 100 m
1 m = 10 dm
1 dm = 10 cm
1 cm = 10 mm

Area

1 km2 = 100 hectares
1 hectare = 100 ares
1 are = 100 m2
1 m2 = 100 dm2
1 dm2 = 100 cm2
1 cm2 = 100 mm2

Volume

1 m3 = 1000 litre
1 litre = 1 dm3
1 litre = 1000 cc
1 litre = 1000 ml

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Length

1 mile = 1.609 km
1 yard = 0.9144 m
1 foot = 0.3048 m
1 inch = 25.4 mm

1 km = 0.6214 mile
1 m = 1.0936 yard
1 m = 3.2808 feet
1 mm = 0.0394 inch

Area

1 sq. mile = 2.59 km2
1 acre = 0.4047 hectare
1 acre = 4046.86 m2
1 sq. yard = 0.8361 m2
1 sq. foot = 0.0929 m2
1 sq. inch = 645.16 mm2

1 km2 = 0.3861 mile2
1 km2 = 247.105 acre
1 hectares = 2.4711 acre
1 m2 = 10.7639 feet2
1 mm2 = 0.0016 inch2

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Volume

1 gallon = 4.5461 litre
1 US gallon = 3.785 litre
1 pint = 0.5683 litre
1 cu. inch = 16.3871 cm3

1 litre = 0.22 gal
1 litre = 0.2642 US gal
1 litre = 1.7598 pint
1 m3 = 219.969 gal
1 m3 = 35.3147 feet3

Weight

1 ton = 1.016 tonne
1 lb = 0.4536 kg
1 oz = 28.3495 g
1 US ton = 0.9072 tonne

1 tonne = 0.9842 ton
1 tonne = 1.1023 US ton
1 kg = 2.2046 lb
1 kg = 35.274 oz



Queen Victoria's diamond necklace. The largest diamond weighs 11.25 carat (1 Carat = 0.2 gram).

Temperature conversion

deg. F= deg. C x 9/5 + 32

[Perfection]

Luminous intensity : candela

Molar volume : mol (mole)

Pressure : newton (N)

[Arnold01]

Dear I have book mark the web page for utilizing the information later whenever there will be some knowledge required to compare the units and conversion.
Big post and thanks.