f Units & Standard of Meas 1. 3. 4. (Unit)
(Unit) () (times)) (Fundamental Unit)
- (mechanics),primary 3) - (thermal, 1)
- (electrical, 1) auxiliary - (Illumination, 1) 1) - (chemical,
(cm, () m) () (g, kg)
(s)) () SI (Derived Unit) (Phys)ical
(Dim (A))= x = mxm = m2 (Length) L (Mas)s))
M (Time) T
L2 L3 LMT 2 kg . m /
s ( ) T -2 ML 2
(System of Uni 2 (Imperial or Britis)h Sys)tem) (Metric Sys)tem)
pound, ounces), dram grai inch, foot, yard mile Pound Troy Pound A)voirdupois) Comparison of Imperial and U.S. volume measures 1 U.S. fluid ounce
= 29.573 529 562 5 mililitres 1.041 Imperial fluid ounces = 28.413 062 5 mililitres 0.961 U.S. fluid ounce = 3.785 411 784 litres
0.833 Imperial gallon 1 Imperial gallon = 4.546 09 litres 1.201 liquid U.S. gallons 1 dry U.S. gallon = 4.404 842 803 2 litres
0.968 Imperial gallon 1 Imperial gallon = 4.546 09 litres 1.032 dry U.S. gallons 1 Imperial fluid ounce 1 liquid U.S. gallon
10 3 1. Univers)al Sys)tem of Weights) & Meas)ures) Manmade Reference Standard
Permanent 2. Meas)ure Prefix - CGS Electros)tatic
- CGS Electromagnetic - TMS - MKS, MKSA) - Gaus)s)ian - Heavis)ide Lorentz CGS (Centimeter, Gram, Second) MKSA) (Mete, Kilogram, Second, A)mp
1 5,000 m2 ft2 1 ft = 30.48 = 0.3048 cm m
1 ft A 5000 0.3048 m 53,820 ft 2 2
(Electric and Mag Volt, A)mpere, Ohm () - (L) CGS Centimeter (C) - (M)
- (T) Gram (G) Second (S) CGS - CGS electrostatic system - CGS electromagnetic system S electrostatic system
(Q) Coulombs) Law) Q1Q2 F k 2 r Q1Q2 r2
F (, dy Q 1,Q2 r Permittivity Coulombs law 1
1 permittivity (Free Space) 1
permittivity (s)pec r 0 0 r
4 ( , ) Q QQ F 1 2 r2
LM Q2 2 2 T 0L 01 2 M 1 2 L3 2 Q T
- CGS (L) - (M) - (T) Centimeter, cm (C) Gram, g (G) Second, s) (S)
Q Q cm3/ 2 g 1/ 2 s 1 Statcoulomb Q I t
I Statcoulomp sec cm3/ 2 g 1/ 2 s 2 Statampere
electromagnetic system magnetic poles)trength Coulombs) Law) m1m2 F k 2 r m1m2
2 r F 2 m1, m2 magnetic poles)trang
r permeability Free s)pace 1 cm
permeability 1 permeability (s)pe r 0 0 r
4 ( , ) m F
m1m2 r 2 LM m 2 2 T 0 L 01 2 M 1 2 L3 2 m
T - CGS (L) - (M) - (T) Centimeter, cm (C) Gram, g (G)
Second, s) (S) m m cm3/ 2 g 1/ 2 s 1
(Practical Unit) - CGS electromagnetic (International Unit) - (International Unit)
1 0.001118 / (Absalute Unit)
1 . 1948 MKS (practical)
Permeability 10-7 ( = 1) SI EC A)mpere - 1954 SI MKSA)
SI SI (Standard)
(Measurement Sta
1 SI ( 90% - 10%)
International (Calibration)
Traceability Sys)tem
4 (International Standard) , (Primary Standard , (Secondary Stan (Working Standard)
(International Standard) International Bureau of Weights) and Meas)ures), Paris)
, (Primary Standard) , (Secondary Standar
(Working Standard)
(Traceabilit
(kg) ( 90% 10%)
International Bureau of Weights) and Meas)ures) Serves), France (m) 1/299,792,458
National Bureau of S = 1 / SI
(s)) 9,192,631,770 caes)ium-133 atom 1. 2. 3.
4. 5. SI A)mpere lectromagnetic 0 I 2l F ( F 2 d
= 2 x 10-7 dM 12 F G I dx 2
I G dM 12 dx x 0 .
Mutual Inductance x 0 nternational A)mpere 1 0.001118 /
jos)ephs)on e - h - Plan Jos)ephs)on
f f V KJ
h f 2e KJ 1 483,597.9 0.2 GHz/V (
1990) (NPL) - 1.01865 V Cadmium Cell : emf of 1.0193, accuracy
(laboratory w)orking) (DC Trans)fer Stan (NBS, NPL) ( 85 %, 11 %,
(Primary Standard) (Thomps)on 2 pF
dc commutated bridge Meas)uring Cap Standard Capacitor - -
orking Standard Capacitor Silver-mica (Primary Standard) - NIST (NBS, U.S.A).) -
