The Units of Measurement Regulations 2009

SCHEDULE Substituted paragraph 2(3) for Schedule 1 to the Units of Measurement Regulations 1986

“(3) SI derived units with special names and symbols

Quantity	Unit Name	Unit Symbol	Expression in terms of other SI units	Expression in terms of SI base units
Plane angle	radian	rad		m.m-1
Solid angle	steradian	sr		m2.m-2
Frequency	Hertz	Hz		s-1
Force	newton	N		m.kg.s-2
Pressure, stress	pascal	Pa	N.m-2	m-1.kg.s-2
Energy, work, quantity of heat	Joule	J	N.m	m2.kg.s-2
Power*, radiant flux	Watt	W	J.s-1	m2.kg.s-3
Electric charge, quantity of electricity	coulomb	C		s.A
Electric potential, potential difference, electromotive force	Volt	V	W.A-1	m2.kg.s-3.A-1
Electric resistance	Ohm		V.A-1	m2.kg.s-3.A-2
Conductance	siemens	S	A.V-1	m-2.kg-1.s3.A2
Capacitance	Farad	F	C.V-1	m-2.kg-1.s4.A2
Magnetic flux	weber	Wb	V.s	m2.kg.s-2.A-1
Magnetic flux density	Tesla	T	Wb.m-2	kg.s-2.A-1
Inductance	Henry	H	Wb.A-1	m2.kg.s-2.A-2
Luminous flux	lumen	lm	cd.sr	cd
Illuminance	Lux	lx	lm.m-2	m-2.cd
Activity (of a radionuclide)	becquerel	Bq		s-1
Absorbed dose, specific energy imparted, kerma, absorbed dose index	Gray	Gy	J.kg-1	m2.s-2
Dose equivalent, dose equivalent index	sievert	Sv	J.kg-1	m2.s-2
Catalytic activity	Katal	kat		mol.s-1

Notes

Units derived from SI base units may be expressed in terms of the units listed in this Schedule.

In particular, SI derived units may be expressed by the special names and symbols given in the above table; for example, the SI unit of dynamic viscosity may be expressed as m^-1. kg.s^-1 or N.s.m^-2 or Pa.s.

*Special names for the unit of power: the name volt-ampere (symbol “VA”) when it is used to express the apparent power of alternating electric current, and var (symbol “var”) when it is used to express reactive electric power.”