Legal Metrology (National Standards) Rules,
2011
Legal Metrology (National
Standards) Rules, 2011
[31st
January, 2011]
In exercise of the powers
conferred by sub-section (1) read with clauses (a), (b), (d) and (e) of
sub-section (2) of Section 52 of the Legal Metrology Act, 2009 (1 of
2010), the Central Government, hereby makes the following rules, namely—
Chapter
I PRELIMINARY
Rule - 1. Short title and commencement.
(1) These rules may be called
the Legal Metrology (National Standards) Rules, 2011.
(2) They shall come into force
on the 1st day of April, 2011.
Rule - 2. Definitions.
In these rules, unless the
context otherwise requires—
(a) “Act” means the Legal
Metrology Act, 2009 (1 of 2010);
(b) “co-efficient” means those
parameters without physical dimension or ratios of quantities of the same kind,
which are necessary for particular measurements or for characterising
properties of substances or mixtures of certain substances;
Illustration—Degree of
alcoholic strength, percentage of sugar and hardness of materials, are examples
of co-efficients.
(c) “derived units” means
units, expressed algebraically in terms of base units, or in terms of base and
supplementary units of weights or measures, by means of mathematical symbols of
multiplication or division, or both.
Explanation I.—Derived
units having special names and symbols (such as ‘Newton’, with symbol ‘N’) may,
by themselves, be used to express other derived units in a simpler way than in
terms of the base units of weights and measures.
Explanation II.—The values
of dimensionless quantities (such as, refractive index, specific gravity,
relative permeability or relative permittivity) are expressed by numbers. In
such cases the corresponding unit shall be the ratio of the relevant two units
and may be expressed by a number;
(d) “General Conference on
Weights and Measures” means the conference General des Poids et Mesures
established under the Metre Convention to which India acceded in 1957;
(e) “International Bureau of
Weights and Measures” means the Bureau International des Poids et Mesures
established under the Convention du Metre, at Sevres in France;
(f) “International Organisation
of Legal Metrology” means the Organisation Internationale de Metrologie Legale established
under the Convention Instituant Une Organisation Internationale de Metrologie
Legale in 1955 to which India acceded in 1956;
(g) “International prototype of
the kilogram” means the prototype sanctioned by the First General Conference on
Weights and Measures held in Paris in 1889 and deposited at the International
Bureau of Weights and Measures;
(h) “International System of
Units” of weights and measures means ‘Le System International d ‘Units’, with
the international abbreviation ‘SI’, established by the General Conference on
Weights and Measures;
Explanation.—‘SI’ is
divided into three classes of units, namely—
(i)
base
units, and
(ii)
derived
units; and
(iii)
supplementary
units;
(i) “permitted units” means the
units which though not part of the SI, are recognised and permitted by the
General Conference on Weights and Measures for general use along with SI units;
(j) “physical constants” means
those constants which express the value of physical invariant in a given system
of units and these constants include—
(i)
those
which correlate two or more physical quantities to express a physical
phenomenon in quantitative terms independent of any material properties; for
example, gravitational constant, velocity of light, etc.
(ii)
those
which correlate the microscopic properties of elementary particles (atoms,
molecules etc.) to the corresponding microscopic properties; for example;
Avogadro constant, Faraday constant etc.
(iii)
those
conversion factors used to express the same parameter in terms of independently
defined units for example, the conversion factor relating the astronomical unit
of parsec to the metre and atomic mass unit to kilogram.
(iv)
those
which describe the material properties of pure substances, for example, thermal
conductivity, specific resistance, etc;
(k) “Schedule” means the
Schedule appended to these rules;
(l) “SI prefix” means the name
and symbol of a prefix used for forming decimal multiples and sub-multiples of
SI units, and of such other units as are permitted subject to any exception or
modification by the General Conference on Weights and Measures or the
International Organisation of Legal Metrology, or both, to be used along with
the SI units;
(m) “special units” means
units, outside, the SI which are ordinarily used in specialised fields of
scientific research and the values of those units expressed in SI units can
only be obtained by experiment, and are, therefore, not known exactly.
Explanation.—The value of
electron volt (the unit of energy) depends upon the experimentally determined
value of the charge of an electron;
(n) “supplementary units” mean
the units of weight or measure which have been specified as such by the General
Conference on Weights and Measures.
Explanation.—Supplementary
units may be used to form derived units;
(o) “symbol” means a letter or
a group of letters written or combined in the specified manner for the
convenient representation of a unit or a group of units;
(p) “temporarily accepted
units” means the unit of weight of measure which have been recognised for the
time being by the General Conference of weights and measures for use along with
SI units.
Chapter
II UNITS
OF WEIGHT OR MEASURE
Rule - 3. Units of weight or measure to be based on metric system.
(1) Every unit of weight or
measure shall be based on the units of the metric systems.
(2) For the purpose of sub-rule
(1),—
(a) the international system of
units as recommended by General Conference on weights and measures, and
(b) such additional units as
may be recommended by the International Organisation of Legal Metrology,
shall be the units of
metric systems.
Rule - 4. Base units of length.
(1) The base unit of length
shall be the metre.
(2) The “metre” is the length
equal to 1650763.73 wavelength in vacuum of the radiation corresponding to the
transition between the levels 2p10 and 5d5 of
the krypton 86 atom.
Rule - 5. Base units of mass.
(1) The base unit of mass shall
be the kilogram.
(2) The “kilogram” is the unit
of mass; equal to the mass of international prototype of kilogram.
Rule - 6. Base unit of time.
(1) The base unit of time shall
be the second.
(2) The “second” is the duration
of 9 192 631 770 periods of radiation corresponding to the transition between
the two hyperfine levels of the ground state of the caesium-133 atom.
Rule - 7. The base unit of electric current.
(1) The base unit of electric
current shall be the ampere.
(2) The “ampere” is that
constant current which if maintained in two straight parallel conductors of
infinite length of negligible circular cross-section, and placed one metre
apart in vacuum, would produce between these conductors a force equal to 2×10−7 newton
per metre of length.
Rule - 8. Base unit of thermodynamic temperature.
(1) The base unit of
thermodynamic temperature shall be the kelvin.
(2) The “kelvin” is the
fraction 1/273.16 of the thermodynamic temperature of triple point of water.
(3) The Kelvin shall also be
used for expressing the interval or difference of temperature.
(4) Zero degree Celsius
corresponds to 273.15 kelvin.
(5) The degree Celsius may also
be used for expressing the interval or difference of temperature, unit degree
Celsius being equal to unit kelvin.
Rule - 9. Base unit of luminous intensity.
(1) The base unit of luminous
intensity shall be the candela.
(2) The “candela” is the
luminous intensity, in the perpendicular direction, of a surface of 1/600,000
square metre of a block body at the temperature of freezing platinum under a
pressure of 101 325 newtons per square metre.
Rule - 10. Base unit of amount of substance.
(1) The base unit of amount of
substance shall be the mole.
(2) The “mole” is the amount of
substance of a system which contains as many elementary entities as there are
atoms in 0.012 kilogram of carbon 12.
(3) When the mole is used, the
elementary entities shall invariably be specified and may be atoms, molecules,
ions, electrons, other particles, or specified groups of such particles.
Rule - 11. Rules of Construction.
In these rules, wherever
the expression “weight” has been used as symbolising the quantity of matter,
such expression shall be construed as representing mass.
Rule - 12. Supplementary Units.
The units defined and
specified in the First Schedule shall be the supplementary units and the symbol
assigned to each such units in that Schedule shall be the symbol of that unit.
Rule - 13. Derived units.
The units defined and
specified in the Second Schedule shall be derived units and the symbol assigned
to each such unit in that Schedule shall be the symbol of that unit and no
other units shall be used for the entities specified in the Second Schedule
except for the purpose of scientific or technological research.
Rule - 14. Decimal multiples and sub-multiples of units.
(1) Decimal multiples and
sub-multiples of base, supplementary, derived or other units shall be formed,
unless otherwise specified, by using either the full name, or symbol of the
SI-prefix specified in the Third Schedule.
(2) The SI-prefixes shall be
used in the manner specified in the Third Schedule.
Rule - 15. Permitted units.
(1) The units specified in the
Fourth Schedule may be used along with the SI units, subject to such
limitations as are specified in that Schedule.
(2) The multiples and
sub-multiples of the units of time and plane angle specified in the Fourth
Schedule shall be formed only in the manner specified in the Schedule.
Rule - 16. Special units.
(1) The units specified in the
Fifth Schedule shall be used in such manner that their values may be expressed
in terms of such SI units or combination of SI units, as may be appropriate.
(2) The multiples and
sub-multiples of the units specified in the Fifth Schedule shall be formed with
the help of SI prefixes specified in the Third Schedule.
Rule - 17. Temporarily accepted units.
The unit of weight or
measure specified in the Sixth Schedule may also be used, subject to the
condition that the Central Government shall, at least once in every ten years
after the commencement of these rules, review the need, or otherwise, for the
continuance for general use of such units:
Provided that such review
may be undertaken earlier by the Central Government either on its own motion or
on the basis of a recommendation made by the General Conference on Weights and
Measures, or the International Organisation of Legal Metrology.
Rule - 18. Units which should be progressively discontinued.
(1) Subject to sub-rule (2),
the centimetre or gram or second units specified in the Seventh Schedule, and
the units of weights and measures specified in the Eighth Schedule (being units
outside the SI), shall not ordinarily be used except for the purpose of
scientific and technological research and no such unit shall ordinarily be used
for the purpose of imparting education.
(2) The use of the units
specified in the Seventh Schedule or, as the case may be, in the Eighth
Schedule, shall not be used in any field except in the field of scientific and
technological research.
(3) While using the units
specified in the Seventh Schedule, or, as the case may be, the Eighth Schedule
for the purpose of scientific and technological research, such units shall be
used only with the corresponding symbols specified in the Schedules aforesaid.
Rule - 19. Physical constants.
The physical constants
specified in the Ninth Schedule and their corresponding numerical values shall
be used for all purposes except for the purpose of research connected with the
determination of their values.
Rule - 20. Coefficient and symbol.
(1) Coefficients include the
terms defined and specified in the Tenth Schedule; the symbol assigned to any
such coefficient in that Schedule shall be the symbol of such coefficient.
(2) Ordinarily, the coefficient
and their respective symbols specified in the Tenth Schedule shall be used:
Provided that any
coefficient which is not specified in the Tenth Schedule but which corresponds
to any coefficient specified in that Schedule, may be used for a period of five
years from the commencement of these rules:
Provided further where any
new coefficient added in the Tenth Schedule, any coefficient corresponding to
the coefficient so added may be used for a period of five years from the date
of addition of such coefficient.
(3) On the expiry of the period
of aforesaid five years, the use of coefficient and their respective symbols as
specified in the Tenth Schedule shall be compulsory.
Explanation.—In the case of
a coefficient the use of which is permissible under any of the provisos to
sub-rule (2), the symbol, if any, attached to such coefficient may also be used
for the same period for which the corresponding coefficient is permitted to be
used.
Rule - 21. Formation of new units.
No new unit or weight or
measure shall be formed or used except for the purpose of scientific and
technological research, without the previous approval of the Central
Government.
Chapter
III NATIONAL
STANDARDS
Rule - 22. National prototypes.
(1) The Central Government
shall, for the purpose of deriving the value of kilogram, cause to be prepared
a national prototype of the kilogram and shall cause its accuracy to be
certified by the International Bureau of Weights and Measures equivalent to the
international prototype of kilogram and shall thereupon deposit the same in the
custody of the National Physical Laboratory, New Delhi.
(2) The Central Government
shall, for the purpose of deriving the value of metre, cause to be prepared a
national prototype of the metre and shall cause its accuracy to be certified by
the International Bureau of Weights and Measures and shall thereupon deposit
the same in the custody of the National Physical Laboratory, New Delhi.
Rule - 23. Custody, maintenance, etc. of national standards of weights and measures.
(1) The work relating to the
realisation, establishment, custody, maintenance, determination, reproduction
and updating of national standards of weights and measures shall, on the
commencement of these rules, be the responsibility of the National Physical
Laboratory.
(2) The Central Government may
call for such reports from, or issue such directions to, the National Physical
Laboratory as it may think fit, in relation to all or any of the matters
specified in sub-rule (1).
Rule - 24. Realisation and establishment of the national standards of weights and measures based on SI units.
(1) The National Physical
Laboratory shall discharge the responsibility of realising and establishing the
national standards of weights and measures on the basis of recommendations made
from time to time, by the General Conference on Weights and Measures or the
International Organisation of Legal Metrology, as the case may be.
(2) The standards of weights
and measures, so realised and established, shall be self-consistent.
(3) For the purpose of
establishing the national standards for the base units other than of mass, the
National Physical Laboratory shall—
(a) prepare or cause to be
prepared such objects or equipments, or reproduce such phenomena, or both, as
may be necessary for the purpose; and
(b) determine or cause to be
determined the value of the national standards as recommended by the General
Conference on Weights and Measures and inter compare them, or cause to be inter
compared, with the corresponding international standards.
(4) For the purpose of deriving
the value of the kilogram, the National Physical Laboratory shall arrange the
periodical determination of the value of the national prototype of the kilogram
and the value of which is so determined, shall be the national standards of
mass.
(5) For the purpose of
establishing the national standards for the derived and supplementary units the
National Physical Laboratory shall prepare such standards, or objects or
equipments, or both and determine periodically their value and accuracy in
relation to the national standards of base units.
Rule - 25. Custody and maintenance of prototype standards.
(1) The national prototype of
the kilogram and other standards, equipments and objects shall remain in the
custody of the National Physical Laboratory, New Delhi.
(2) The national prototype of
the kilogram and every other national standard, standard equipments and objects
shall be maintained and realised periodically in accordance with such
instructions as the General Conference on Weights and Measures or the
International Organisation of Legal Metrology or any organisation constituted
by either of them may issue from time to time.
(3) Where no instructions have
been issued by the International Organisation referred to in sub-rule (2), any
Consultative Committee constituted may compile instructions for the proper
maintenance of national prototype, national standards, standards equipments and
objects.
(4) The National Physical
Laboratory shall arrange, where necessary, to have the national prototype and
national standards of physical measurements realised and established in
accordance with the recommendations of the General Conference on Weights and
Measures and to get them calibrated on inter compared with reference to the
appropriate international standards of physical measurements at periodical
interval of not more than ten years.
(5) The value of the national
prototype and other national standards shall be the value determined by the
National Physical Laboratory or assigned by the National Physical Laboratory on
the basis of the technical information provided by the International Bureau of
Weights and Measures and the National Physical Laboratory shall publish such
values periodically but in any case at least once in every five years.
(6) The value determined in
accordance with sub-rule (5) shall be deemed to represent the higher obtainable
accuracy of such value in the country.
Chapter
IV REFERENCE,
SECONDARY AND WORKING STANDARDS
Rule - 26. Reference standard.
The expression “reference
standard” means set of standard weight or measure which is made or manufactured
by or on behalf of the Central Government for the verification of any secondary
standard.
Rule - 27. Secondary standard.
The expression “secondary standard”
means set of standard weight or measure which is made or manufactured by or on
behalf of the Central Government or State Government for the verification of
any working standard.
Rule - 28. Working standard.
The expression “working
standard” means set of standard weight or measure which is made or manufactured
by or on behalf of the Central Government or State Government for the
verification of any standard weight or measure, other than national prototype,
reference standard or secondary standards.
Rule - 29. Standards which are to be fabricated by the Mint.
Unless otherwise specified
by the Central Government, all the reference, secondary and working standards
of mass and length and secondary and working standards of capacity shall be
fabricated by the Metrological Wing of the Government of India Mint in Mumbai.
Rule - 30. Places where reference, secondary and working standards be kept.
(1) There shall be established
by the Central Government, at such places as it may think fit, Reference
Standard Laboratories for maintaining such reference, secondary and working
standards as may be needed by the Central Government for the purpose of the
Act.
(2) The Indian Institute of
Legal Metrology or any other Laboratory specified by the Central Government for
this purpose may also maintain such reference, secondary and working standards,
as may be necessary, for their functioning as a Metrological Laboratory of the
level of a Reference Standard Laboratory.
(3) The Government of India
Mint at Mumbai may also maintain such reference, secondary and working
standards as may be necessary for carrying out the work referred to in Rule 29.
Rule - 31. Period and manner of verification of reference, secondary and working standards.
(1) Every reference standard
shall be verified and certified in terms of the National Standards by the
National Physical Laboratory, at an interval not exceeding three years:
Provided that in the case
of length measures such interval shall not exceed five years.
(2) Every secondary standard
shall be verified against the appropriate reference standard by the Reference
Standard Laboratory, at an interval not exceeding two years.
(3) Every working standard
shall be verified against the appropriate secondary standard, by any of the
laboratories where secondary standards are maintained, at an interval not
exceeding one year.
Rule - 32. Maintenance of reference, secondary and working standards.
Every reference standard,
every secondary standard and every working standard, irrespective of the place
where they are kept, shall be maintained as far as practicable in accordance
with the guidelines issued by the National Physical Laboratory from time to
time.
Rule - 33. Repeal and savings.
(1) The Standards of Weights
and Measures (National Standards) Rules, 1988 (herein under referred to as the
said rules) are hereby repealed:
Provided that such repeal
shall not affect:
(a) the previous operations of
the said rules or anything done or omitted to be done or suffered therein; or
(b) any right, privilege,
obligation or liability acquired, accrued or incurred under the said rules; or
(c) any penalty, forfeiture or
punishment incurred in respect of any offence committee against the said rules;
or
(d) any investigation, legal
proceedings or remedy in respect of any such right, privilege, obligation,
liability, penalty, forfeiture or punishment as aforesaid.
And any such investigation,
legal proceedings or remedy may be instituted, continued or enforced and any
such penalty, forfeiture or punishment may be imposed as if the said rules had
not been rescinded.
(2) Notwithstanding such repeal
anything done or any action taken or purported to have been done or taken
including approval of letter, exemption granted, fees collected, any
adjudication, enquiry or investigation commenced, license and registration of
manufacturers, dealers, importers of weights and measures, or show cause
notice, decision, determination, approval, authorisation issued, given or done
under the said rules shall if in force at the commencement of the said rules
continue to be in force and have effect as if issued, given or done under the
corresponding provisions of these rules.
(3) The provisions of these
rules shall apply to any application made to the Central Government or as the
case may be the State Government under the said rules for licence, registration
of manufacturers, importers, dealers, repairers of weights and measures pending
at the commencement of these rules and to any proceedings consequent thereon
and to any registration granted in pursuance thereof.
(4) Any legal proceeding pending
in any court under the said rules at the commencement of these rules may be
continued in that court as if these rules had not been framed.
(5) Any appeal preferred to the
Central Government or as the case may be the State Government under the said
rules and pending shall be deemed to have been made under the corresponding
provisions of these rules.
THE
FIRST SCHEDULE
(See Rule
12)
Supplementary
Units and their symbols.—
(1) Unit of plane angle.—The
unit of plain angle shall be the radian. (symbol: rad)
The radian is the plane
angle between two radii of a circle which cutoff, on the circumference, an arc
equal in length to the radius.
(2) Unit of solid angle.—The
unit of solid angle shall be the steradian. (Symbol: sr)
The steradian is the solid
angle which, having its vertex in the centre of a sphere, 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.
THE
SECOND SCHEDULE
(See Rule
13)
Derived
Units and their Symbols
Part
I
Derived
Unit in relation to Space and Time.—
(1) Unit of Area: The unit of
area shall be the square metre. (Symbol: m2)
The square metre is the
area of a square with sides of one metre each.
(2) Unit of Volume: The unit of
volume shall be the cubic metre. (Symbol: m3)
The cubic metre is the
volume of a cube with sides of one metre each.
(3) Unit of frequency: The unit
of frequency shall be the hertz. (Symbol: Hz)
The hertz is the frequency
of a periodic phenomenon, the period of which is one second.
1Hz = 1/1s.
(4) Unit of angular velocity:
The unit of angular velocity shall be the radian per second. (Symbol: rad/s)
The radian per second is
the angular velocity of a body, rotating around the fixed axis, which rotates
through one radian in one second, when set in uniform rotation.
(5) Unit of angular
acceleration: The unit of angular acceleration shall be the radian per second
square. (Symbol: rad/s2)
The radian per second
squared is the angular acceleration of a body, rotating around the fixed axis,
which when set in uniform varying rotation, changes angular velocity at the
rate of one radian per second in one second.
(6) Unit of speed and velocity:
The unit of speed and velocity shall be the metre per second. (Symbol: m/s or
ms−1)
The metre per second is the
velocity (speed) of a body, in motion which traverse a distance of one metre in
one second when set in uniform motion.
(7) Unit of acceleration: The
unit of acceleration shall be the metre per second squared. (Symbol: m/s2 or
ms−2)
The metre per second
squared is the acceleration of a body in motion which, when set in uniformly
varying motion, changes its velocity at the rate of one metre per second in one
second.
(8) Unit of rotational
frequency: The unit of rotational frequency shall be the second raised to the
power minus one. (Symbol: s−1)
The second raised to the
power minus one is the rotational frequency of a uniform rotatory movement
which produces one complete revolution in one second.
(9) Unit of wave number: The
unit of wave number shall be the metre raised to the power minus one. (Symbol:
m−1)
The metre raised to the
power minus one is the number of waves of a monochromatic radiation which can
be accommodated, in the direction of its propagation, in a length equal to one
metre.
(10) Unit of vergency of optical
system: The unit of vergency of optical system shall be the metre raised to the
power minus one. (Symbol: m−1)
The metre raised to the
power minus one is the vergency of an optical system, the focal distance of
which is one metre in a medium having refractive index of unit.
Note 1.—This unit is
also called “per metre” or “dioptre”.
Note 2.—The metre
raised to the power minus one symbol m−1 is the unit of wave
number as well as that of vergency of optical system. The context in which the
said unit is used will indicate whether the unit relates to the wave number or
vergency of optical system.
Part
II
Derived
Units in Relation of Mechanics
(1) Unit of density and mass
density—The unit of density and mass density shall be the kilogram per cubic
metre. (Symbol: kg/m3 or Kgm−3)
The kilogram per cubic
metre is the density or mass density of a homogenous body having a mass of one
kilogram and a volume of one cubic metre.
(2) Unit of concentration—The
unit of concentration shall be the kilogram per cubic metre. (Symbol: kg/m3 or
Kgm−3)
The kilogram per cubic
metre is the concentration of a homogenous solution having a total volume of
one cubic metre and containing a mass of one kilogram of the given substance.
(3) Unit of force—The unit of
force shall be the newton. (Symbol: N)
The newton is the force
which gives to a mass of one kilogram an acceleration of one metre per second
squared.
1 N = 1 kg. 1m/s2
(4) Unit of moment of force—The
unit of moment of force shall be the newton metre. (Symbol: Nm)
The newton metre is the
moment of force produced in a body by a force of one newton acting at a
perpendicular distance of one metre from the fixed axis around which the body
turns.
1 N.m = m2. Kg.s−2
Note:—The unit of moment of
force shall not be written as joule (J) because it is Nm.
(5) Unit of Pressure—The unit
of pressure shall be the Pascal. (Symbol: Pa)
The Pascal is the pressure
which, acting on plane surface of one square metre exerts on that area a total
force of one newton.
1 Pa = 1 N/m2 or
1 N.m−2
(6) Unit of tensile
strength—The unit of tensile strength shall be Mega Pascal. (Symbol: MPa or M
N/m2)
The tensile strength is the
highest force, when applied normal to the cross-section of a test piece which
it can withstand, divided by the original area of the cross section.
(7) Unit of dynamic
viscosity—The unit of dynamic viscosity shall be the Pascal second. (Symbol:
Pa.S)
The Pascal second is the
dynamic viscosity of a homogenous liquid in which the straight and uniform
movement of a plane surface of one square metre produces a retarding force of
one newton, when there is a velocity difference of one metre per second between
two parallel planes separated by one metre.
(8) Unit of kinematic
viscosity—The unit of kinematic viscosity shall be the square metre per second.
(Symbol: m2/s or m2.s−1)
The square metre per second
is the kinematic viscosity of a liquid which has a dynamic viscosity of one
Pascal second and a density of one kilogram per cubic metre.
(9) Unit of surface tension—The
unit of surface tension shall be the newton per metre. (Symbol: N/m)
The newton per metre is the
surface tension produced when a force of one newton acts over a length of one
metre on the surface of a liquid separating that liquid from the material
surrounding it.
(10) Unit of work, energy and
quantity of heat—The unit of energy, work and quantity of heat shall be the
joule. (Symbol: J)
The joule is the work done
when the point of application of one newton moves a distance of one metre in
the direction of the force.
1 J = 1 N. 1m.
(11) Unit of power, radiant flux
and heat flux—The unit of power, radiant flux and heat flux shall be the watt.
(Symbol: W)
The watt is the power of an
energy system in which one joule of energy is uniformly transferred in one
second.
1 W = 1 J/1s.
(12) Unit of volume flow—The
unit of volume flow shall be cubic metre per second. (Symbol: m3/s
or m3.s−1)
The cubic metre per second
is the volume delivered by the uniform discharge of one cubic metre traversing
the given cross-section in one second.
(13) Unit of mass flow—The unit
of mass flow shall be the kilogram per second. (Symbol: kg/s or kg.s−1)
The kilogram per second is
the mass delivered by the uniform discharge of a mass of one kilogram
traversing the given cross-section in one second.
(14) Unit of specific volume—The
unit of specific volume shall be the cubic metre per kilogram. (Symbol: m3/kg)
The cubic metre per
kilogram is the specific volume of a homogenous body having a volume of one
cubic metre and a mass of one kilogram.
Part
III
Derived
Units in Relation to Heat
(1) Unit of entropy—The unit of
entropy shall be the joule per kelvin. (Symbol: J/K)
The joule per kelvin is the
increase of entropy of a system receiving a quantity of heat equal to one joule
at the constant thermodynamic temperature of one kelvin, provided that no
irreversible change takes place in the system.
(2) Unit of specific
entropy—The unit of specific entropy shall be the joule per kilogram kelvin.
[Symbol: J/(kg.K)]
The joule per kilogram
kelvin is the specific entropy of a system of homogenous mass of one kilogram
receiving a quantity of heat equal to one joule at the constant thermodynamic temperature
of one kelvin, provided that no irreversible change takes place in the system.
(3) Unit of heat capacity—The
unit of heat capacity shall be the joule per kelvin. (Symbol: J/K)
The joule per kelvin is the
heat capacity of a homogenous body in which a quantity of heat equal to one
joule produces an increase of one kelvin in the thermodynamic temperature.
(4) Unit of specific heat
capacity—The unit of specific heat capacity shall be the joule per kilogram
kelvin. [Symbol: J/(kg.K)]
The joule per kilogram kelvin
is the specific heat capacity of a homogenous body having a mass of one
kilogram in which quantity of heat equal to one joule produces an increase of
one kelvin in the thermodynamic temperature.
(5) Unit of latent heat—The
unit of latent heat shall be the joule per kilogram. (Symbol: J/kg)
The joule per kilogram is
the heat exchanged by one kilogram of substance to change from one phase to
another at the temperature of its changing phase.
(6) Unit of specific energy—The
unit of specific energy shall be the joule per kilogram. (Symbol: J/kg)
The joule per kilogram is
the specific energy of a system of homogenous mass of one kilogram having the
internal energy of one joule.
(7) Unit of thermal
conductivity—The unit of thermal conductivity shall be the watt per metre kelvin.
[Symbol: W/(m.K)]
The watt per metre kelvin
is the thermal conductivity of a homogenous body in which a difference of one
kelvin in the thermodynamic temperature produces a radiant flux of one watt
between two parallel planes, each having an area of one square metre, placed
one metre apart.
(8) Unit of energy density—The
unit of energy density shall be the joule per cubic metre. (Symbol: J/m3)
The joule per cubic metre
is the energy density of a system of homogenous mass of volume one cubic metre
and having the radiant energy of one joule.
(9) Unit of heat flux
density—The unit of heat flux density shall be the watt per square metre.
(Symbol: W/m2)
The watt per square metre
is heat flux density of a surface of one square metre in area radiating out
energy at the rate of one joule per second.
Part
IV
Derived
units in relation of Electricity and Magnetism
(1) Unit of quantity of
electricity and electric charge—The unit of quantity of electricity and
electric charge shall be the coulomb. (Symbol: C)
The coulomb is the quantity
of electricity carried in one second by a current of one ampere.
1C = 1 A. 1s
(2) Unit of electric charge
density—The unit of electric charge density shall be the coulomb per cubic
metre. (Symbol: C/m3)
The coulomb per cubic metre
is the electric charge density of a homogenous mass or system of volume one
cubic metre and having a charge of one coulomb.
(3) Unit of electric flux
density—The unit of electric flux density shall be coulomb per square metre.
(Symbol : C/m2)
The coulomb per square
metre is the electric flux density when a condenser, having plates of infinite
area/size, parallel to each other, is charged, in vacuum, with a quantity of
electricity equal to one coulomb per one square metre of area of the plates.
(4) Unit of electric tension,
electric potential and electromotive force—The unit of electric tension,
electric potential and electromotive force shall be the volt. (Symbol: V).
The volt is the potential
difference between two points of a conducting wire carrying a constant current
of one ampere, when the power dissipated between these points is equal to one
watt.
1 V= 1W/1A.
(5) Unit of electric field
strength—The unit of electric field strength shall be the volt per metre.
(Symbol: V/m)
The volt per metre is the
electric field strength of an electric field which produces a force equal to
one newton in a body charge with a quantity of electricity equal to one
coulomb.
(6) Unit of electric
resistance—The unit of electric resistance shall be the ohm. (Symbol: Ω)
The ohm is the electric
resistance between two points of a conductor when a constant potential
difference of one volt, applied to these points, produces in the conductor a
current of one ampere, the conductor not being the seat of any electromotive
force.
1Ω = 1 V/1A.
(7) Unit of conductance—The unit
of conductance shall be the siemens. (Symbol: S)
The siemens is the
conductance of a conductor having a resistance of one ohm.
(8) Unit of capacitance—The
unit of capacitance shall be the farad. (Symbol: F)
The farad is the
capacitance between the conductors of a capacitor across which there appears a
potential difference of one volt when it is charged by a quantity of
electricity of one coulomb.
1F = 1C/1V
(9) Unit of permittivity—The
unit of permittivity shall be farad per metre. (Symbol: F/m)
The farad per metre is the
permittivity of the medium which gives a capacitance of one farad per square
metre of area of two parallel plates separated by a distance of one metre.
(10) Unit of inductance—The unit
of inductance shall be the henry. (Symbol: H)
The henry is the inductance
of a closed circuit in which an electromotive force of one volt is produced
when the electric current in the circuit varies uniformly at the rate of one
ampere per second.
(11) Unit of permeability—The
unit of permeability shall be the henry per metre. (Symbol: H/m)
The henry per metre is the
permeability of a material surrounded by a single turn of flat sheet conductor
including an area of one square metre and length one metre which gives an
inductance of one henry.
(12) Unit of magnetic flux and
flux of magnetic induction—The unit of magnetic flux and flux of magnetic
induction shall be the weber. (Symbol: Wb)
The weber is the magnetic
flux which, linking a circuit of one turn, would produce in it an electromotive
force of one volt if it were reduced to zero at a uniform rate in one second.
1 Wb = 1 V.1s
(13) Unit of magnetic induction
and magnetic flux density—The unit of magnetic induction and magnetic flux
density shall be the tesla. (Symbol: T)
The tesla is the uniform
magnetic induction which, distributed evenly over a surface of one square
metre, produces a total magnetic flux of one weber while passing over the
surface.
1T = 1Wb/1m2
(14) Unit of magnetic field
strength—The unit of magnetic field strength shall be the ampere per metre.
(Symbol: A/m or A.m-1)
The ampere per metre is the
magnetic field strength produced in vacuum along the surface of a circular
cylinder with a circumference of one metre, by a current of intensity of one
ampere, maintained in a straight conductor of infinite length, of negligible
circular cross-section, which forms the axis of the said cylinder.
(15) Unit of current density—The
unit of current density shall be the ampere per square metre. (Symbol: A/m2)
The ampere per square metre
is the current density in a linear conductor when a current of intensity one
ampere flows uniformly through a cross-section of the conductor equal to one
square metre, perpendicular to the direction of flow of the current.
Part
V
Derived
Units in Relation to Electromagnetic Radiation and Light
(1) Unit of radiant
intensity—The unit of radiant intensity shall be the watt per steradian.
(Symbol: W/sr)
The watt per steradian is
the radiant intensity of a point source uniformly emitting a radiant flux of
one watt within a solid angle of one steradian.
(2) Unit of irradiance—The unit
of irradiance shall be the watt per square metre. (Symbol: W/m2)
The watt per square metre
is the irradiance produced by a radiant flux of one watt, distributed uniformly
over an element having a surface of one square metre.
[See also (1) above]
(3) Unit of radiance—The unit
of radiance shall be the watt per square metre steradian. (Symbol: W/m2.sr)
The watt per square metre
steradian is the radiance of a source radiating one watt per steradian per
square metre of projected area.
(4) Unit of luminance—The unit
of luminance shall be the candela per square metre. (Symbol: cd/m2)
The candela per square
metre is the luminance perpendicular to the plane surface of one square metre
of a source, the luminous intensity of which perpendicular to this source is
one candela.
(5) Unit of luminous flux—The
unit of luminous flux shall be the lumen. (Symbol: lm)
The lumen is the luminous
flux emitted in a solid angle of one steradian by a uniform point source having
a luminous intensity of one candela. 1 lm = 1 cd. 1 sr
(6) Unit of illuminance—The
unit of illuminance shall be the lux. (Symbol: lx)
The lux is the illuminance
produced by a luminous flux of one lumen, uniformly distributed over a surface
of area one square metre. 1 lx = 1 lm/1m2
Part
VI
Derived
Units in Relation to ionizing Radiations
(1) Unit of
activity (radioactivity)—The unit of activity (of a radioactive source)
shall be the becqueral. (Symbol: Bq)
The becqueral is the
activity of a radioactive source in which one transformation or one transition
takes place in one second.
1 Bq = 1/1.s
(2) Unit of absorbed dose—The
unit of absorbed dose shall be gray which is equivalent to one joule per
kilogram. (Symbol: Gy)
The gray is the dose
absorbed in an element of substance of mass one kilogram to which an energy of
one joule is communicated by an ionizing radiation, having a constant density
of radiant flux,
1 Gy = 1 J/1 kg
Part
VII
Derived
Units in Relation to Physical Chemistry and Molecular Physics
(1) Unit of
concentration (of amount of substance)—The unit of concentration (of
amount of substance) shall be the mole per cubic metre. (Symbol: mol/m3)
The mole per cubic metre is
the concentration of a homogenous solution having a total volume of one cubic metre
and containing one mole of the given substance.
(2) Unit of molar energy—The
unit of molar energy shall be the joule per mole. (Symbol: J/mol)
The joule per mole is the
molar energy of one mole of substance having the energy of one joule.
(3) Unit of molar entropy—The
unit of molar entropy shall be the joule per mole kelvin. (Symbol: J/mol.K)
The joule per mole kelvin
is the molar entropy of a system of homogenous mass having a substance equal to
one mole receiving a quantity of heat equal to one joule at the constant
thermodynamic temperature of one kelvin provided that no irreversible change
takes place in the system.
(4) Unit of molar heat
capacity—The unit of molar heat capacity shall be the joule per mole kelvin.
(Symbol: J/mol.K)
The joule per mole kelvin
is the molar heat capacity of a homogenous body having an amount of substance
equal to one mole, in which a quantity of heat equal to one joule produces an
increase of one kelvin in the thermodynamic temperature.
THE
THIRD SCHEDULE
(See Rule
14)
Names,
Magnitudes and Symbols of SI Prefixes and Principles of use of SI Prefixes
(1) Names, Magnitudes and
Symbols of SI Prefixes—The names of prefixes, their magnitudes and symbols
shall be as given in Table 1.
Table
1
Names
of Prefixes, their Magnitudes and Symbols
|
Name of Prefix
|
Magnitude of Prefix
|
Symbol of Prefix
|
|
exa
|
1018
|
E
|
|
peta
|
1015
|
P
|
|
tera
|
1012
|
T
|
|
giga
|
109
|
G
|
|
mega
|
106
|
M
|
|
kilo
|
103
|
k
|
|
hecta
|
102
|
h
|
|
deca
|
101
|
da
|
|
deci
|
10−1
|
d
|
|
centi
|
10−2
|
c
|
|
milli
|
10−3
|
m
|
|
micro
|
10−6
|
μ
|
|
nano
|
10−9
|
n
|
|
pico
|
10−12
|
p
|
|
femto
|
10−15
|
f
|
|
atto
|
10−18
|
a
|
Explanation.—The unit of
length is metre with symbol m: after adding a prefix c' for centi we get “cm”
as new unit symbol. This can be raised to a positive exponent 3 to give the
unit of volume. Similarly this can be combined with another unit say ‘kg’ and
by giving it negative exponent 3 to indicate density in kg per cm3.
Kg/cm3 =
kg/10−6 m3 = 106 kg/m3
Similarly g/cm3 =
1000 kg/m3
(2) Symbol how to be combined
with units—
(a) The symbol of the prefix
shall be placed before the unit symbol without any intermediary space or dot.
(b) The combination shall form
the symbol of the multiple and sub-multiple of the unit.
(c) The symbol for the prefix
shall be considered to be combined with the symbol of the unit to which it is
directly linked together, forming a new unit symbol, which can be combined with
other unit symbols to form composite unit symbols.
(3) Errors how to be avoided—To
avoid errors in calculations, all quantities shall be expressed in SI units,
and powers of 10 shall be used.
(4) Exponents—An exponent
affixed to a symbol containing a prefix indicates that the multiple or
sub-multiple of the unit is raised to the power expressed by the exponent.
Illustration
1 cm = 10−2 m
gives 1 cm3 = 10−6 m3 and 1 cm−1 =
102 m−1
(5) Compound units how to be
formed—Only one prefix shall be used in forming the multiples of a compound
unit, and compound prefixes shall not be used.
Illustration
Write nm (nano metre),
instead of mμm.
(6) Use of prefixes with unit
mass—Notwithstanding that the base unit of mass contains a prefix, names of
decimal multiples or sub-multiples of the unit of mass shall be formed by
attaching prefixes to the word gram.
Illustration
Write milligram (mg) but
not micro kilogram (μkg).
(7) Printing—
(1) Symbols of units—
(a) Shall be printed in roman
(upright) type irrespective of the type used in the rest of the text;
(b) Shall remain unaltered in
the plural;
(c) Shall be written, without a
final full stop (period) unless the context otherwise requires; and
(d) shall be placed after the
complete numerical value in the expression for a quantity, leaving a space
between the numerical value and the unit.
(2) The symbol for units of
weight or measures shall be printed in lower case letters except that the first
letter shall be printed in upper case when the name of the unit is derived from
a proper name.
Illustration
m - metre
s - second
A - Ampere
Wb - weber
(8) Multiplication of units—
(1) When a compound unit is
formed by multiplication of two or more units, the multiplication may be
indicated in one of the following ways:
m, N, N.m, Nm
(2) In using a symbol of a unit
of weight or measure which coincides with the symbol for a prefix, special care
shall be taken to avoid confusion.
Illustration
The unit “newton metre”
shall be written Nm or m.N to avoid confusion with mN, the millinewton.
(9) Division of Units—
(1) When a compound is formed
by dividing one unit by another the division shall be indicated in one of the following
ways—
m/s or by writing the
product of m and s−1 as ms−1
(2) The letter p shall not be
used to denote division.
Illustration
Do not write kmph, write
km/h or km.h-1
(3) In no case shall more than
one solidus (oblique stroke) on the same line be included in such a combination
unless a parenthesis is inserted to avoid ambiguity:
Illustration
Write m/s2 or
m.s−2 but not m/s/s/
(4) In complicated cases,
negative powers or parenthesis shall be used.
Illustration
Write m.kg/(s3.A)
or m.kg.s−3A−1 but not m.kg/s3A
(10) Expression of results—
(1) The appropriate integral
multiple and sub-multiple to which a unit is to be expressed shall be selected
in such a manner that the numerical value to be expressed is between 0.1 and
1000
Illustration
1.2 × 104 N
may be written as 12kN
0.00 394 m may be written
as 3.94 mm
1 40 1 Pa may be written as
1.401 kPa
3.1 × 10−8 may
be written as 31 ns
(2) In a table of values for
the same quantity or in a discussion of such values within a given context the
same integral multiple or sub-multiple of a unit may be used for all items,
even when some of the numerical values may be outside the range of 0.1 to 1000.
(3) For the purpose of
expression of dimensions in mechanical engineering drawings only the millimetre
shall be used.
(11) Expression of Numbers—
(1) To express numbers in
connection with units of weights and measures, the dot shall be used to
separate the integral part of numbers from the decimal part.
(2) Numbers shall be divided in
groups of three starting from the decimal point in order to facilitate regarding
and neither dots nor commas shall be inserted in the space between such group
of numbers.
Illustration
Write 3211 468.022 82
Not 3.211.468.022.82
or 3.211.468.022.82
THE
FOURTH SCHEDULE
(See Rule
15)
Units
Permitted to be used with base, Supplementary or Derived Units
(1) Permitted units of time—
(1) The permitted units in
relation to time shall be as follows, namely—
(i)
the
minute, equal to 60 second (Symbol: min),
(ii)
the
hour, equal to 3600 seconds or 60 minutes (Symbol: h), and
(iii)
the
day, equal to 86,000 seconds or 24 hours (Symbol: d).
The week, month and year
shall correspond to the Saka Calendar or the Gregorian calendar.
(2) Permitted units of plane
angle—The permitted units in relation to plane angle shall be as follows,
namely—
(i)
The
degree, equal to tt/180
radian (Symbol: °),
(ii)
The
minute, equal to tt/10800
radian or (1/60)° (Symbol: ‘), and
(iii)
The
second equal to tt/648000
radian or (1/60) (Symbol: “).
(3) Permitted unit of volume—
(1) The permitted unit of
volume shall be litre (Symbol: 1). The litre shall be equal to one thousand
part of the cubic metre.
1 1 = 1 dm3 =
10−3 m3
(2) The litre shall not be used
for work involving precise measurements.
(4) Permitted unit of mass—
(1) The permitted unit of mass
shall be the tonne. (Symbol: t). The tonne shall be equal to 1000 kilograms.
(2) Only the prefixes “kilo”,
“mega”, “giga” and “tera” specified in the Third Schedule may be used with the
tonne.
THE
FIFTH SCHEDULE
(See Rule
16)
Special
Units and their Symbols
(1) Special unit of energy—The
special unit of energy acquired by an electron shall be the electron volt.
(Symbol: eV)
The electron volt is the
energy acquired by an electron in passing through a potential difference of one
volt in vacuum.
1 eV= 1.602 177 33 × 10−19 J
(2) Special unit of atomic
mass—The special unit of mass of an atom shall be unified atomic mass unit.
(Symbol: u)
The unified atomic mass
unit is equal to the fraction 1/12 of the mass of an atom of the nucleus 12C.
1 u = 1.660 5402 × 10−27 kg
(3) Special units of stellar
distance—
(1) The first special unit of
stellar distance shall be the astronomical unit. (Symbol: AU)
The astronomical unit of
distance is the length of the radius of the unperturbed circular orbit of a
body of negligible mass moving round the Sun with a sidereal angular velocity
of 0.017 202 098 950 radian per day of 86 400 ephemeris seconds.
1 AU = 149 600 × 106 m
Note.—The symbol for
stellar distance is not internationally uniform, for example the symbol used
for stellar distance is UÅ in France, ÅU in England and ÅE in Germany.
(2) The second special unit of
stellar distance shall be parsec. (Symbol: pc)
The parsec is the distance
at which one astronomical unit subtends an angle of one second of arc.
1 pc = 206 265 Å;U = 30857 × 1012 m.
THE
SIXTH SCHEDULE
(See Rule
17)
Temporarily
accepted Units
(1) Unit of nautical
distance—The unit of distance for use in marine and aerial navigation shall be
the nautical mile is equal to a distance of 1852 metres.
(2) Unit of nautical
velocity—The unit of nautical velocity for use in marine and aerial navigation
shall be the knot. The knot is the velocity equal to one nautical mile per
hour.
1 knot = (1852/3600) m/s,
i.e. 0.514 444 m/s.
(3) Unit of wavelength of
light—
(1) The unit of wavelength of
light shall be the angstrom. (Symbol: Å;). The angstrom is equal to 0.1 nanometre.
1 Å; = 0.1 nm = 10−10 m
(4) Unit of land measurement—
(1) The first unit for
measurement of land area shall be the “are”. (Symbol: a)
The “are” is the area of a
square with sides of length 10 metres.
1 a = dam2 =
102 m2
(2) The second unit for
measurement of land area shall be hectare. (Symbol: ha) The hectare is the area
of a square with sides of length 100 metres.
1 ha = 1hm2 =
104 m2
(3) The prefixes specified in
the Third Schedule shall not be used with the “are” or hectare.
(5) Unit of nuclear
cross-section—The unit of nuclear cross-section shall be the barn. (Symbol: b)
The barn is the nuclear cross-section area equal to 100 square femtometres.
1 b = 10−28 m2
(6) Unit of pressure of
fluid—The unit of pressure of fluid shall be the bar. (Symbol: bar)
The bar shall be equal to
100 000 pascals.
(7) Unit of standard
atmosphere—The unit of standard atmosphere shall be 101 325 pascals.
The standard atmosphere is
the pressure exerted by air at mean sea level under the standard conditions
specified by the General Conference on Weights and Measures.
(8) Special unit for
acceleration due to gravity—The special unit for acceleration due to gravity
for use in geodesey and geophysics shall be the gal. (Symbol: Gal)
The gal is equal to 1/100
metre per second square.
(9) Unit of activity of
radio-nuclides—The unit of activity of radio-nuclides shall be the curie.
(Symbol: Ci)
The curie is the quantity
of any radioactive nuclide in which the number of disintegrations per second is
3.7 × 1010 or
1 Ci = 3.7 × 1010 Bq
(10) Unit of exposure dose—The
unit of exposure dose shall be the roentgen. (Symbol: R)
The roentgen is the
exposure dose of an ionizing radiation which can produce in a quantity of air
having a mass of one kilogram, ions of the same sign carrying a total charge
2.58 × 10−4 coulomb, the density of energy flux being the same
throughout the quantity of air taken.
R = 2.58 × 10−4 C/kg
(11) Unit of velocity—The unit
of velocity shall be kilometre per hour. (Symbol: km/h) The kilometre per hour
is the velocity of a body in motion which when set in a uniform traverses a
distance of one kilometre in one hour.
(12) Unit of mass of special
value—The unit of mass of special value shall be the caret. (Symbol: c)
The caret is equal to five
thousandth part of the kilogram. It shall be used for commercial transactions
in diamonds, pearls and precious stones.
1 c = 200mg
(13) Unit of mass for special
use—The unit of mass for special use shall be the quintal. (Symbol: q)
The quintal is equal to 100
kilograms. The quintal may be used in large commercial transactions in food
grain, farm produce and other consumer commodities.
THE
SEVENTH SCHEDULE
(See Rule
18)
C.G.S.
units with special names
|
Name of Unit
|
Symbol
|
Value in terms of base, supplementary or derived
unit
|
|
(1)
|
erg
|
erg
|
1 erg = 10−7 J
|
|
(2)
|
dyne
|
dyn
|
1 dyn = 10−5 N
|
|
(3)
|
poise
|
P
|
1 P-1dyns/cm2 = 0.1 Pa.s
|
|
(4)
|
stokes
|
st
|
1 st = 1 cm2/s = 10−4 m2/s
|
|
(5)
|
gauss
|
Gs
|
1 Gs = 10−4 T
|
|
(6)
|
oersted
|
Oe
|
1 Oe = 1000 A/m
4tt
|
|
(7)
|
maxwell
|
Mx
|
1 Mx = 10−8 Wb
|
|
(8)
|
stilb
|
sb
|
1 sb = 1 cd/cm2 = 104 cd/m2
|
|
(9)
|
phot
|
ph
|
1 ph = 10 lx
|
THE
EIGHTH SCHEDULE
(See Rule
18)
Units
outside the International System
|
Name of Unit
|
Value in terms of base, supplementary or derived
units
|
|
(1)
|
fermi
|
1 fermi = 1 fm = 10−15 m
|
|
(2)
|
torr
|
1 torr = 101325 Pa
760
|
|
(3)
|
kilogram-force (kgf)
|
1 kgf = 9.806 65 N
|
|
(4)
|
calorie (cal)
|
1 cal = 4.1868 J
|
|
(5)
|
micron (μ)
|
1 μ = 1 μm = 10−6 m
|
|
(6)
|
X unit
|
1 X unit = 1.002 = 10−6 nm
approximately
|
|
(7)
|
stere (st)
|
1 st = 1 m3
|
|
(8)
|
gamma (Y)
|
1 Y = 1nT = 10−9 T
|
|
(9)
|
Y
|
1 Y = 1 μg = 10−9 kg
|
|
(10)
|
λ
|
1 λ = 1μl = 10−61
|
THE
NINTH SCHEDULE
(See Rule
19)
Important
Physical Constants
|
Quantity
|
Symbol
|
Value
|
Units
|
Relative Uncertainty (ppm)
|
|
GENERAL CONSTANTS
Universal Constants
|
|
speed of light in vacuum
|
c
|
299792458
|
ms−1
|
(exact)
|
|
permeability of vacuum
|
μ?
|
4tt ×
10−7 = 12.566370614
|
NA-2 10−7 NA−2
|
(exact)
|
|
permittivity of vacuum
|
ε?
|
1/μ?C2 = 8.854187817…
|
10−12 Fm−1
|
(exact)
|
|
Newtonian constant of gravitation
|
G
|
6.67259 (85)
|
10−11 m3kg-1s−2
|
128
|
|
Planck constant in electron volts, h/{e}
|
h
|
6.6260755(40) 4.1356692(12)
|
10−34 Js
10−15 eVs
|
0.60 0.30
|
|
h/(2tt)
in electron volts, h/{e}
|
?
|
1.05457266(63) 6.5821220(20)
|
10−34 Js
10−16 eVs
|
0.60 0.30
|
|
Planck mass, (hc/G)1/2
|
mp
|
2.17671(14)
|
10−8 kg
|
64
|
|
Planck length h/mpc = (hG/c3)1/2
|
lp
|
1.61605(10)
|
10−35m
|
64
|
|
Planck time tp/c = (hG/c5)1/2
|
tp
|
5.39056(34)
|
10−44s
|
64
|
|
Electromagnetic Constants
|
|
elementary charge
|
e
|
1.60217733(49)
|
10−19C
|
0.30
|
|
e/h
|
2.41798836 (72)
|
1014AJ
|
0.30
|
|
Magnetic flux quantum, h/2e
|
Φ°
|
2.06783461(61)
|
10−15Wb
|
0.30
|
|
Josephson frequency-voltage ratio
|
2e/h
|
4.8359767(14)
|
10−14 HzV-1
|
0.30
|
|
quantized Hall conductance
|
e2/h
|
3.87404614(17)
|
10−5S
|
0.045
|
|
quantized Hall resistance, h/e2=½μ?/α
|
RH
|
25812.8056(12)
|
Ω
|
0.045
|
|
Bohr magneton, e?/2me
|
μB
|
9.2740154(31)
|
10−24JT−1
|
0.34
|
|
in electron volts, μB/{e}
|
|
5.78838263(52)
|
10−5 eVT−1
|
0.089
|
|
in hertz, μB/h
|
|
1.39962418(42)
|
10−10HzT−1
|
0.30
|
|
in wavenumbers, μB/hc
|
|
46.686437(14)
|
m−1 T−1
|
0.30
|
|
in kelvins, μB/k
|
|
0.6717099(57)
|
KT−1
|
8.5
|
|
nuclear magneton, eh/2mp
|
μN
|
5.0507866(17)
|
10−27 JT−1
|
0.34
|
|
in electron volts, μN/{e}
|
|
3.15245166(28)
|
10−8 eVT−1
|
0.089
|
|
in hertz, μN/h
|
|
7.6225914(23)
|
MHzT−1
|
0.30
|
|
in wavenumbers, μN/hc
|
|
2.54262281(77)
|
10−2 m−1T−1
|
0.30
|
|
in kelvins, μN/k
|
|
3.658246(31)
|
10−4KT−1
|
8.5
|
|
Atomic Constants
|
|
fine-structure constant, ½μ?ce2/h
|
α
|
7.29735308(33)
|
10−3
|
0.045
|
|
inverse fine-structure constant
|
α−1
|
137.0359895(61)
|
|
0.045
|
|
Rydberg constant, ½meca2/h
|
R∞
|
10973731.534(13)
|
m−1
|
0.0012
|
|
in hertz, R∞c
|
|
3.2898419499(39)
|
1015Hz
|
0.0012
|
|
in joules, R∞hc
|
|
2.1798741(13)
|
10−18J
|
0.60
|
|
in eV, R∞hc/{e}
|
|
13.6056981(81)
|
eV
|
0.30
|
|
Bohr radius, α/4tt R∞
|
ao
|
0.529177249(24)
|
10−10m
|
0.045
|
|
Hartree energy, e2/4ttε0 α0 = 2 R∞ hc
|
Eh
|
4.3597482(26)
|
10−8J
|
0.60
|
|
in eV, Eh/{e}
|
|
27.2113961(81)
|
eV
|
0.30
|
|
quantum of circulation
|
h/2me
|
3.63694807(33)
|
10−4m2s−1
|
0.089
|
|
h/me
|
7.27389614(65)
|
10−4m2s−1
|
0.089
|
|
Electron
|
|
electron mass
|
me
|
9.1093897(54)
|
10−31 kg
|
0.59
|
|
|
5.48579903 (13)
|
10−4 u
|
0.023
|
|
in electron volts, mec2/{e}
|
|
0.51099906(15)
|
MeV
|
0.30
|
|
electron-muon mass ratio
|
me/mμ
|
4.83633218(71)
|
10−3
|
0.15
|
|
electron-proton mass ratio
|
me/mp
|
5.44617013(11)
|
10−4
|
0.020
|
|
electron-deuteron mass ratio
|
me/md
|
2.72443707(6)
|
10−4
|
0.020
|
|
electron-α-particle mass ratio
|
me/mα
|
1.37093354(3)
|
10−4
|
0.021
|
|
electron specific charge
|
−e/me
|
−1.75881962(53)
|
1011 Ckg−1
|
0.30
|
|
electron molar mass
|
M(e), Me
|
5.48579903(13)
|
10−7kg/mol
|
0.023
|
|
Compton wavelength, h/mec
|
λc
|
2.42631058(22)
|
10−12 m
|
0.089
|
|
λc/2tt=α
ao = a2/4ttR∞
|
λc
|
3.86159323(35)
|
10−13m
|
0.089
|
|
classical electron radius, α2 ao
|
re
|
2.81794092(38)
|
10−15m
|
0.13
|
|
Thomson cross-section, (8tt/3)r2e
|
oe
|
066524616(18)
|
10−23m2
|
0.27
|
|
electron magnetic moment
|
μe
|
928.47701(31)
|
10−26 JT−1
|
0.34
|
|
in Bohar magnetons
|
μe/uB
|
1.001 159 652 193 (10)
|
|
1 × 10−5
|
|
in nuclear magnetons
|
μe/uN
|
1838.282000(37)
|
|
0.020
|
|
electron magnetic moment anomaly, μe/μB-1
|
ae
|
1.159652193(10)
|
10−5
|
0.0086
|
|
electron g-factor, 2(1+αe)
|
ge
|
2.002319304386(20)
|
|
1 × 10−3
|
|
electron-muon magnetic moment ratio
|
μe/μμ
|
206.766967(30)
|
|
0.15
|
|
electron-proton magnetic moment ratio
|
μe/μp
|
658.2106881(66)
|
|
0.010
|
|
Muon
|
|
muon mass
|
mμ
|
1.8835327(11)
|
10−26kg
|
0.61
|
|
|
0.113428913(17)
|
u
|
0.15
|
|
in electron volts, mμc2/{e}
|
|
105.658389(34)
|
MeV
|
0.32
|
|
muon-electron mass ratio
|
mμ/me
|
206.768262(30)
|
|
0.15
|
|
muon molar mass
|
M(μ), Mμ
|
1.134289 13(17)
|
10−4kg/mol
|
0.15
|
|
muon magnetic moment
|
μμ
|
4.4904514(15)
|
10−26 JT−1
|
0.33
|
|
in Bohr magnetons
|
μμ/μB
|
4.84197097(71)
|
10−3
|
0.15
|
|
in nuclear magnetons
|
μμ/μN
|
8.8905981(13)
|
|
0.15
|
|
muon magnetic moment anomaly [μμ(eh/2mμ)]−1
|
aμ
|
1.1659230(84)
|
10−3
|
7.2
|
|
muon g-factor, 2(1+aμ)
|
gμ
|
2.002331846(17)
|
|
0.0084
|
|
muon-proton magnetic moment ratio
|
μμ/μP
|
3.18334547(47)
|
|
0.15
|
|
Proton
|
|
proton mass
|
mp
|
1.6726231(10)
|
10−27kg
|
0.59
|
|
|
1.007276470(12)
|
u
|
0.012
|
|
in electron volts, mpc2/{e}
|
|
938.27231(28)
|
MeV
|
0.30
|
|
proton-electron mass ratio
|
mp/me
|
1836.152701(37)
|
|
0.020
|
|
proton-muon mass ratio
|
mp/mμ
|
8.8802444(13)
|
|
0.15
|
|
proton specific charge
|
e/mp
|
9.5788309(29)
|
107Ckg−1
|
0.30
|
|
proton molar mass
|
M(p), MP
|
1.007276470(12)
|
10−3 kg/mol
|
0.012
|
|
proton Compton wavelength, h/mpc λcp/2tt
|
λcp
λcp
|
1.32141002(12)2.10308937(19)
|
10−15m 10−16m
|
0.0890.089
|
|
proton magnetic moment
|
μp
|
1.41060761(47)
|
10−26 JT−1
|
0.34
|
|
in Bohr magnetons
|
μpμB
|
1.521032202(15)
|
10−23
|
0.010
|
|
in nuclear magnetons
|
μp/μN
|
2.792847386(63)
|
|
0.023
|
|
diamagnetic shielding correction for protons in
pure water, spherical sample, 25°C, 1-μp/μp
|
σH2O
|
25.689(15)
|
10−6
|
|
|
shielded proton moment (H2O, sph.
25°C)
|
μp
|
1.41057138(47)
|
10−26 JT−1
|
0.34
|
|
in Bohar magnetons
|
μp/μB
|
1.520993129(17)
|
10−3
|
0.011
|
|
in nuclear magnetons
|
μp/μN
|
2.792775642(64)
|
|
0.023
|
|
proton gyromagnetic ratio
|
Yp
|
26752.2128(81)
|
104s−1T−1
|
0.30
|
|
Yp/2tt
|
42.577469(13)
|
MHzT−1
|
0.30
|
|
uncorrected (H2O, sph. 25°C)
|
Yp
|
26751.5255(81)
|
10−4s−1T−1
|
0.30
|
|
Yp/2tt
|
42.576375(13)
|
MHzT−1
|
0.30
|
|
Neutron
|
|
neutron mass
|
mn
|
1.6749286(10)
|
10−27kg
|
0.59
|
|
|
1.008664904(14)
|
u
|
0.014
|
|
in electron volts, mnc2/{e}
|
|
939.56563(28)
|
MeV
|
0.30
|
|
neutron-electron mass ratio
|
mn/me
|
1838.683662(40)
|
|
0.022
|
|
neutron-proton mass ratio
|
mn/mp
|
1.001378404(9)
|
|
0.009
|
|
neutron molar mass
|
M(n), Mn
|
1.008664904(14)
|
10−3 kg/mol
|
0.014
|
|
neutron Compton wavelength, h/mec
|
λc, n
|
1.31959110(12)
|
10−15 m
|
0.089
|
|
λc, n/2tt
|
λc, n
|
2.10019445(19)
|
10−16 m
|
0.089
|
|
neutron magnetic moment
|
μn
|
0.96623707(40)
|
10−26 JT−1
|
0.41
|
|
in Bohr magnetons
|
μn/μB
|
1.04187563(25)
|
10−3
|
0.24
|
|
in nuclear magnetons
|
μn/μN
|
1.91304275(45)
|
|
0.24
|
|
neutron-electron magnetic moment ratio
|
μn/μe
|
1.04066882(25)
|
10−3
|
0.24
|
|
neutron-proton magnetic moment ratio
|
μn/μp
|
0.68497934(16)
|
|
0.24
|
|
Deuteron
|
|
deuteron mass
|
md
|
3.3435860(20)
|
10−27 kg
|
0.59
|
|
|
2.013553214(24)
|
u
|
0.012
|
|
in electron mass, mdc2/{e}
|
|
1875.61339(57)
|
MeV
|
0.30
|
|
deuteron-electron mass ratio
|
md/me
|
3670.483014(75)
|
|
0.020
|
|
deuteron-proton mass ratio
|
md/mp
|
1.999007496(6)
|
|
0.003
|
|
deuteron molar mass
|
M(d), Md
|
2.013553214(24)
|
10−27 kg/mol
|
0.012
|
|
deuteron magnetic moment
|
μd
|
0.43307375(15)
|
10−26 JT−1
|
0.34
|
|
in Bohr magnetons
|
μd/μB
|
0.4669754479(91)
|
10−3
|
0.019
|
|
in nuclear magnetons
|
μd/μN
|
0.857438230(24)
|
|
0.028
|
|
deuteron-electron magnetic moment ratio
|
μd/μe
|
0.4664345460(91)
|
10−3
|
0.019
|
|
deuteron-proton magnetic moment ratio
|
μd/μp
|
0.3070122035(51)
|
|
0.017
|
|
Physico-Chemical Constants
|
|
Avogadro constant
|
NA, L
|
6.02213367(36)
|
1023mol−1
|
0.59
|
|
atomic mass constant mu=1/12m(12C)
|
mu
|
1.6605402(10)
|
10−27 kg
|
0.59
|
|
in electron volts, muc2/{e}
|
|
931.49432(28)
|
Mev
|
0.30
|
|
Faraday constant
|
F
|
96485.309(29)
|
Cmol−1
|
0.30
|
|
molar Planck constant
|
Nah
|
3.99031323(36)
|
10−10 Jsmol−1
|
0.089
|
|
Nahc
|
0.11962658(11)
|
Jm mol−1
|
0.089
|
|
molar gas constant
|
R
|
8.314510(70)
|
Jmol−1 K−1
|
8.4
|
|
Boltznann constant R/NA
|
k
|
1.380658(12)
|
10−23JK−1
|
8.5
|
|
in electron volts, k/{e}
|
|
8.617385(73)
|
10−5 eVK−1
|
8.4
|
|
in hertz, k/h
|
|
2.083674(18)
|
1010HzK−1
|
8.4
|
|
in wavenumbers, k/hc
|
|
69.50387(59)
|
m−1K−1
|
8.4
|
|
molar volume (ideal gas), RT/p
T = 273.15K
p = 101325 Pa
|
Vm
|
22.41410(19)
|
L/mol
|
8.4
|
|
Loschmidt constant, NA/Vm
|
no
|
2.686763(23)
|
10−25 m−3
|
8.5
|
|
T=273.15K, p=100 kPa
|
Vm
|
22.71108(19)
|
L/mol
|
8.4
|
|
Sackur-Tetrode constant (absolute entropy
constant)
|
So/R
|
−1.151693(21)
|
|
18
|
|
5/2 + In
{(2ttmukT1/h2)3/2 kT1/po}
T = 1 k
po = 100 kPa
pʵ = 101 325 Pa
|
|
−1.164856(21)
|
|
18
|
|
Stefan-Boltzmann constant, (tt2/60)k4/h3c2
|
σ
|
5.67051(19)
|
10−8Wm−2K-4
|
34
|
|
first radiation constant 2tthc2
|
c1
|
3.7417749(22)
|
10−16Wm2
|
0.60
|
|
second radiation constant, hc/k
|
c2
|
0.01438769(12)
|
mK
|
8.4
|
|
Wien displacement law constant,
|
b
|
2.897756(24)
|
10−3mK
|
8.4
|
|
b = λmaxT =
C2/4.96511423….
|
|
|
|
|
THE
TENTH SCHEDULE
(See Rule
20)
The
following co-efficients shall be used for the purpose of these rules—
1. Alcoholic strength.—
(a) The “alcoholic strength by
volume” of a mixture of water and alcohol is the ratio of the volume of
alcohol, measured at 20°C, contained in the mixture to the total volume of the
mixture measured at the same temperature. The symbol is “%Vol”.
(b) The “alcoholic strength by
mass” of a mixture of water and alcohol is the ratio of the mass of alcohol
contained in the mixture to the total mass of the mixture. The symbol is
“%mass”.
For the purpose of the
inter-relation between these two strengths and between the density of the
aqueous solution of alcohol, the International Recommendation No. 22 on
Alcoholometry, together with the International Alcoholometric Tables, shall be
used.
2. Hardness numbers for
materials.—
(a) Brinell Hardness Number.—A
number related to the size of the permanent impression made by a ball indenter
of specified size, pressed into the surface of the material under a specified
load. The surface area of the impression is determined from the average
measured diameter of the rim of the impression and from the ball diameter. In
reporting Brinell hardness number, the International Recommendation No. 9, on
Verification and Calibration of Brinell Hardness Standards Blocks, shall be
used.
(b) Diamond Pyramid or Vickers
Hardness Number.—A number obtained by dividing the load in kilograms applied to
a square-based pyramidal diamond indenter having included face angles of 136°
by the surface area of the impression calculated from the measured diagonal of
the impression. In reporting diamond pyramid hardness, the International
Recommendation No. 10, on Verification and Calibration of Vickers Hardness
Standards Blocks, shall be used.
(c) Rockwell Hardness Number.—A
number derived from net increase in depth of impression as the load on an
indenter is increased from a fixed minimum load to high load and then returned
to the minimum load. In reporting Rockwell hardness number on Rockwell B scale,
the International Recommendation No. 11, on Verification and Calibration of
Rockwell B Hardness Standardised Blocks, shall be used.
Similarly, in reporting
Rockwell hardness number on Rockwell C scale, the International Recommendation
No. 12, on Verification and Calibration of Rockwell C Hardness Standardised
Blocks, shall be used.
3. For the purpose of
determining the sugar content present in the sugar solutions either of the two
following coefficients may be used. Degree Brix or sugar degree (°S)—
(a) Degree Brix is the
percentage of sucrose present by mass in the sugar solution. In reporting the
degree Brix, Indian Standard specification for Brix hydrometers: (IS:
7324-1974) shall be used, till such time, the Director of Legal Metrology or
the International Organisation of Legal Metrology prepares such document.
(b) Sugar degree on the
international sugar scale is defined as follows—
The 100° S point of the
International Sugar Scale is fixed by the optical rotation ‘μ’ undergone by the
polarized light of the green line of the mercury isotope 198 (μ-546.2271 mm in
vacuum). When passing through a 200.000 mm length of sucrose solution in pure
water, kept at a temperature of 20.00°C, and containing 26.0160 g, weighed in a
vacuum of pure sucrose per 100.000 cm3 of solution ‘normal’
sugar solution.
A mass of 26.0160 g of
sucrose corresponds to 26.000 g when this sucrose is weighed in air by means of
weights with a density of 8000 kg/m3 in air, at a standard
pressure of 101325 Pascal, at a temperature of 20°C and a relative humidity of
50%, the density of this air therefore being 1.2 kg/m3.
4. Relative Humidity.—
It is the ratio of the
actual vapour pressure of water vapours present in air at the temperature of
measurement of the saturation vapour pressure over a plane liquid water surface
at the same temperature. This is expressed as a pure number as percentage.
5. pH is the logarithm
to the base 10 of the inverse of the hydrogen ion concentration in a dilute
ionic solution.
Explanation.—A 0.04 molar
hydrochloric acid solution will have hydrogen ion concentration of 10−1.4
mol and its pH value is 1.4. Similarly, 0.001 mol hydrochloric acid solution will
have the hydrogen ion concentration of 10−3 mol and its pH
value is 3.