1.1

mass

kilogram

kg

The SI definition of kilogram

Note:   Because the name for the legal unit of measurement for mass contains a prefix, the names for other units of measurement for mass are formed by combining prefixes with gram as described in Part   4 in the way mentioned in guidelines issued by the Chief Metrologist under subsection   7B(1) of the Act.

1.2

amount of substance

mole

mol

The SI definition of mole

1.3

length

metre

m

The SI definition of metre

1.4

time

second

s

The SI definition of second

1.5

luminous intensity

candela

cd

The SI definition of candela

1.6

thermodynamic temperature

kelvin

K

The SI definition of kelvin

1.7

electric current

ampere

A

The SI definition of ampere

2.1

frequency

hertz

Hz

The frequency of a regularly recurrent phenomenon that repeats itself once each second.

2.2

force

newton

N

The force that, when applied to a body having a mass of 1   kilogram, causes an acceleration of 1 metre per second squared in the direction of the application of the force.

2.3

pressure

pascal

Pa

The pressure resulting from a force of 1 newton applied uniformly over an area of 1   square metre.

2.4

energy, work

joule

J

The work done or the energy expended when a force of 1   newton moves the point of application 1 metre in the direction of that force.

2.5

power, including sound power

watt

W

The power used when work is done or energy is expended at the rate of 1 joule per second.

2.6

electric charge

coulomb

C

The quantity of electric charge that is transferred each second by an electric current of 1   ampere.

2.7

potential difference, electro - motive force

volt

V

The potential difference that exists between 2 points on a conductor carrying an unvarying electric current of 1   ampere when the power dissipated between those points is equal to 1 watt.

2.8

electric capacitance

farad

F

The electric capacitance that exists between 2 conductors when the transfer of an electric charge of 1 coulomb from one to the other changes the potential difference between them by 1   volt.

2.9

electric conductance

siemens

S

The electric conductance of a conductor that has an electric resistance of 1 ohm.

2.10

electric inductance

henry

H

The electric inductance of a closed circuit in which an electromotive force of 1 volt is produced when the electric current that traverses the circuit varies uniformly at the rate of 1   ampere per second.

2.11

electric resistance

ohm



The electric resistance between 2   points on a conductor that does not contain any source of electromotive force when a constant potential difference of 1   volt maintained between those points results in a current of 1   ampere in the conductor.

2.12

magnetic flux

weber

Wb

The magnetic flux that, linking a circuit of 1 turn, produces in that circuit an electromotive force of 1   volt if the magnetic flux is reduced to zero at a uniform rate in 1 second.

2.13

magnetic flux density

tesla

T

The magnetic flux density that results if a magnetic flux of 1   weber is uniformly distributed over a plane 1 square metre in area, the direction of the magnetic flux density being perpendicular to that plane.

2.14

luminous flux

lumen

lm

The luminous flux emitted into a solid angle of 1 steradian by an isotropic point source having a luminous intensity of 1   candela.

2.15

illuminance

lux

lx

The illuminance produced at the surface of a sphere having a radius of 1 metre by a point source that:

(a) is situated at its centre; and

(b) has a luminous intensity of 1   candela in all directions.

2.16

activity of a radionuclide

becquerel

Bq

The activity of a radionuclide that is undergoing 1 transformation per second on average.

2.17

absorbed dose, absorbed dose index, kerma, specific energy imparted

gray

Gy

The absorbed dose, absorbed dose index, kerma or specific energy imparted when 1 joule is imparted to 1 kilogram of irradiated matter

2.18

dose equivalent

sievert

Sv

The sievert is the dose equivalent or dose equivalent index where:

(a) an absorbed dose of ionising radiation equal to 1 gray is delivered to a biological material; and

(b) the conditions under which the dose is delivered satisfy the formula:

Q ï‚´ N = 1

where:

Q is a factor that is the quality factor representing the effect on the detriment of the microscopic distribution of absorbed energy; and

N is a factor that is the product of all other modifying factors specified by the International Commission on Radiological Protection as at the commencement of these regulations.

2.19

plane angle

radian

rad

The radian is the plane angle between 2 radii of a circle that cut off on the circumference an arc equal in length to the radius.

2.20

solid angle

steradian

sr

The steradian is the solid angle that has its vertex in the centre of a sphere and 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.

2.21

catalytic activity

katal

kat

The katal is a unit of catalytic activity equal to 1 mole per second.

3.1

sound power level

decibel

dB

In measuring sound power level in decibels, the number of decibels is the number equal to 10 times the logarithm to the base 10 of the ratio of the sound power in the particular case expressed in watts to a reference sound power of
10 -12 watts.

3.2

sound pressure level

decibel

dB

In measuring sound pressure level in decibels, the number of decibels is the number equal to 20 times the logarithm to the base 10 of the ratio of the root - mean - square sound pressure in the particular case expressed in pascals to a reference sound pressure of
2 ï‚´ 10 -5 pascals.

3.3

sound intensity level

decibel

dB

In measuring sound intensity level in decibels, the number of decibels is the number equal to 10 times the logarithm to the base 10 of the ratio of the sound intensity in the particular case expressed in watts per square metre to a reference sound intensity of 10 -12 watts per square metre.

3.4

area

hectare

ha

10 4 m 2

3.5

energy

electron - volt

eV

The kinetic energy acquired by an electron in passing through a potential difference of 1 volt in vacuum.

1 eV = 1.602   177   33 ï‚´ 10 -19   J

3.6

kinematic viscosity

stokes

St

10 -4 m 2 /s

3.7

length

nautical mile

n mile

1852 m

3.8

mass

tonne

t

10 3 kg

3.9

mass

metric carat

CM or ct

0.2 ï‚´ 10 -3 kg

3.10

plane angle

degree

º

 / 180 rad

3.11

plane angle

minute

ï‚¢

1 / 60   / 180 rad

3.12

plane angle

second



1 / 3   600 ï‚´  / 180 rad

3.13

time

day

d

86   400 s

3.14

time

hour

h

3   600 s

3.15

time

minute

min

60 s

3.16

temperature

degree Celsius

ºC

A degree Celsius is equal in magnitude to a kelvin.

t(ºC) = T(K) - 273.15

where:

t(ºC) is the numerical value of temperature in degrees Celsius.

T(K) is the numerical value of temperature in kelvins.

3.17

velocity

knot

kn

1852 / 3600 m/s

3.18

viscosity

poise

P

10 -1 Pa.s

3.19

volume

litre

L or l

10 -3 m 3

4.1

mass

gram

g

10 - 3 kg

4.2

length

micron

µm

10 - 6 m

4.3

area

square metre

m 2

base unit

4.4

area

square kilometre

km 2

10 6 m 2

4.5

square decimetre

dm 2

10 - 2 m 2

4.6

square centimetre

cm 2

10 - 4 m 2

4.7

square millimetre

mm 2

10 - 6 m 2

4.8

square micrometre

µm 2

10 - 12 m 2

4.9

volume

cubic kilometre

km 3

10 9 m 3

4.10

cubic metre

m 3

base unit

4.11

cubic decimetre

dm 3

10 - 3 m 3

4.12

cubic centimetre

cm 3

10 - 6 m 3

4.13

cubic millimetre

mm 3

10 - 9 m 3

4.14

hectolitre

hL or hl

10 - 1 m 3

4.15

millilitre

mL or ml

10 - 6 m 3

4.16

density

kilogram per cubic metre

kg/m 3

base unit

4.17

velocity and speed

metre per second

m/s

base unit

4.18

acceleration

metre per second squared

m/s 2

base unit

4.19

luminance

candela per square metre

cd/m 2

base unit

4.20

absorbed dose, absorbed dose index, kerma, specific energy imparted

rad

rad

10 - 2 Gy

4.21

activity of a radionuclide

curie

Ci

3.7 ï‚´ 10 10 Bq

4.22

dose equivalent

rem

rem

10 - 2 Sv

4.23

exposure

roentgen

R

0.258 ï‚´ 10 - 3 C/kg

4.24

frequency

revolutions per minute

r/min

60 Hz

4.25

revolutions per second

r/s

1 Hz

4.26

apparent power

volt ampere

VA

V rms A rms

4.27

reactive power

volt ampere reactive

var

V rms A rms sin  where  radians is the phase angle between the electro - motive force (emf) and the current

4.28

apparent energy

volt ampere hour

Vah

V rms A rms h

4.29

reactive energy

volt ampere hour reactive

varh

V rms A rms hsin  where  radians is the phase angle between the electro - motive force (emf) and the current