అంతర్జాతీయ ప్రమాణాల పద్ధతి: కూర్పుల మధ్య తేడాలు

దిద్దుబాటు సారాంశం లేదు
దిద్దుబాటు సారాంశం లేదు
పంక్తి 1:
[[File:SI base unit.svg|thumb |upright=1.2|ఏడు SI బేస్ యూనిట్ నిర్వచనాల మధ్య లింకులు. ఎగువ నుండి సవ్యదిశలో: [[సెకను]] ([[కాలం]]), [[మీటరు]] ([[పొడవు]]), [[ఆంపియర్]] ([[ఎలెక్ట్రిక్ కరెంట్]]), మోల్ (పదార్థరాశి), [[కిలోగ్రాము]] ([[ద్రవ్యరాశి]]), [[కెల్విన్‌]] ([[ఉష్ణోగ్రత]]), మరియు కాండిలా (కాంతి తీవ్రత).]]
'''అంతర్జాతీయ ప్రమాణాల పద్ధతి''' అనేది మెట్రిక్ వ్యవస్థ యొక్క ప్రామాణిక ఆధునిక రూపం. ఈ వ్యవస్థ యొక్క పేరుని ఫ్రెంచ్ పేరు సిస్టెమె ఇంటర్నేషనల్ డి'యునిటెస్ నుండి, ఎస్ఐ (SI) కు కుదించారు లేదా సంక్షిప్తీకరించారు. అంతర్జాతీయ ప్రమాణాల పద్ధతి అనేది 7 ఆధార ప్రమాణముల ఆధారంగా కొలత పధ్ధతి: ఇవి మీటరు (పొడవు), కిలోగ్రాము (ద్రవ్యరాశి), సెకను (కాలం), ఆంపియరు (విద్యుత్ ప్రవాహం), కెల్విన్ (ఉష్ణగతిక ఉష్ణోగ్రత), మోల్ (పదార్థరాశి), మరియు కాండిలా (కాంతి తీవ్రత). ఈ బేస్ యూనిట్లు ప్రతి ఇతర కలయికలో ఉపయోగించవచ్చు. ఇది SI ఉత్పన్న ప్రమాణాలు సృష్టిస్తుంది, ఇవి వాల్యూమ్, శక్తి, ఒత్తిడి, మరియు వేగం వంటి ఇతర పరిమాణాలు వివరించడానికి ఉపయోగించుకోవచ్చు. ఈ పద్ధతి దాదాపు ప్రపంచవ్యాప్తంగా ఉపయోగిస్తారు. కేవలం మయన్మార్, లైబీరియా, మరియు యునైటెడ్ స్టేట్స్ కొలత యొక్క అధికారిక పద్ధతి గా ఎస్ఐ వాడటంలేదు.<ref name="ciawf">{{cite web |title=Appendix G: Weights and Measures |url=https://www.cia.gov/library/publications/the-world-factbook/appendix/appendix-g.html |work=The World Facebook |publisher=[[Central Intelligence Agency]] |date=2013 |accessdate=5 April 2013}}</ref> అయితే ఈ దేశాలలో ఎస్ఐ అనేది సాధారణంగా శాస్త్రం మరియు ఔషధంలో ఉపయోగిస్తారు.
 
== Units of measurement ==
 
=== Base units ===
 
The SI '''base units''' are [[measurement]]s used by scientists and other people around the world. All the other units can be written by combining these seven base units in different ways. These other units are called "derived units".
 
{| class="wikitable" style="margin:1em auto 1em auto"
|+ SI base units
|-
!Unit name
!Unit<br>symbol
![[Physical quantity|Quantity]] measured
!General definition
|-
![[metre]]
|style="text-align:center" |m
|[[length]]
|
*'''Original''' (1793): {{sfrac|1|{{gaps|10|000|000}}}} of the [[meridian]] through [[Paris]] between the [[North Pole]] and the [[Equator]]
*'''Current''' (1983): The distance traveled by light in a [[vacuum]] in {{sfrac|1|{{gaps|299|792|458}}}} second
|-
![[kilogram]] <ref group=note>The kilogram is the SI base unit of mass and is used in the definitions of derived units. However, units of mass are ''named'' using prefixes as if the gram were the base unit.</ref>
|style="text-align:center" |kg
|[[mass]]
|
*'''Original''' (1793): The '''grave''' was defined as being the weight [mass] of one cubic decimetre of pure water at its [[freezing point]].
*'''Current''' (1889): The mass of the International Prototype Kilogram, a cylinder of [[platinum]]-[[iridium]] [[alloy]] kept at the [[International Bureau of Weights and Measures]] near [[Paris]].
|-
![[second]]
|style="text-align:center" |s
|[[time]]
|
*'''Original''' (Medieval): {{sfrac|1|{{gaps|86|400}}}} of a day
*'''Current''' (1967): The time needed for {{gaps|9|192|631|770}} periods or cycles of the radiation created by [[electron]]s moving between two [[energy level]]s of the [[caesium]]-133 [[atom]].
|-
![[ampere]]
|style="text-align:center" |A
|[[electric current]]
|
*'''Original''' (1881): A tenth of the ''abampere'', the unit of current used in the electromagnetic [[CGS]].<ref>{{cite book
|url = http://books.google.co.uk/books?id=m7c6AAAAIAAJ&pg=PA322&lpg=PA322&dq=cgs+unit+of+current+1881&source=bl&ots=Lw5kV5-jd4&sig=mytqNION410y2qYnGEGn-Hcbu6o&hl=en&sa=X&ei=qaWkUKfiFeeZ0QXpvYC4CA&ved=0CCAQ6AEwADgK#v=onepage&q=cgs%20unit%20of%20current%201881&f=false
|page = 322
|title = Magnetism and Electricity
|last1 = McKenzie
|first1 = A.E.E
|publisher = [[Cambridge University Press]]
|year = 1961}}</ref>
*'''Current''' (1946): The current passing through two very long and thin wires placed 1 m apart that produces an [[attraction|attractive]] [[force]] equal to {{val|2|e=-7}} newton per metre of length.
|-
![[kelvin]]
|style="text-align:center" |K
|[[temperature]]
|
*'''Original''' (1743): The '''centigrade scale''' is obtained by assigning 0° to the [[freezing point]] of water and 100° to the [[boiling point]] of water.
*'''Current''' (1967): The fraction {{sfrac|1|273.16}} of the thermodynamic temperature of the [[triple point]] of water.
|-
![[Mole (unit)|mole]]
|style="text-align:center" |mol
|[[amount of substance]]
|
*'''Original''' (1900): The molecular weight of a substance in mass grams.
*'''Current''' (1967): The same amount as the number of [[atom]]s in 0.012 kilogram of [[carbon]]-12.<ref group=note>When the mole is used, the substance being measured must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.</ref>
|-
![[candela]]
|style="text-align:center" |cd
|[[luminous intensity]]
|
*'''Original''' (1946): {{sfrac|1|60}} of the brightness per square centimetre of a [[black body]] at the temperature where [[platinum]] freezes.
*'''Current''' (1979): The luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency {{val|540|e=12}} hertz and that has a radiant intensity in that direction of {{sfrac|1|683}} [[watt]] per [[steradian]].
|-
|colspan=5|
;Notes
{{reflist|group=note}}
|}
 
=== Derived units ===
Derived units are created by combining the base units. The base units can be divided, multiplied, or raised to [[exponent|powers]]. Some derived units have special names. Usually these were created to make calculations simpler.
 
{| class="wikitable" style="margin:1em 0 1em 0; text-align:center"
|+ style="font-size:larger;font-weight:bold;"|Named units derived from SI base units
|-
! Name
! [[Symbol]]
! [[Physical quantity|Quantity]]
! Definition <br>other units
! Definition<br>[[SI base unit]]s
|-
| '''[[radian]]'''
| '''rad'''
| style="text-align:left" | plane [[angle]]
|
| −
|-
| '''[[steradian]]'''
| '''sr'''
| style="text-align:left" | solid angle
|
| −
|-
| '''[[hertz]]'''
| '''Hz'''
| style="text-align:left" | [[frequency]]
|
| s<sup>−1</sup>
|-
| '''[[newton (unit)|newton]]'''
| '''N'''
| style="text-align:left" | [[Force (physics)|force]], [[weight]]
|
| m∙kg∙s<sup>−2</sup>
|-
| '''[[pascal (unit)|pascal]]'''
| '''Pa'''
| style="text-align:left" | [[pressure]], [[Stress (physics)|stress]]
| N/m<sup>2</sup>
| m<sup>−1</sup>∙kg∙s<sup>−2</sup>
|-
| '''[[joule]]'''
| '''J'''
| style="text-align:left" | [[energy]], [[Mechanical work|work]], [[heat]]
| N∙m
| m<sup>2</sup>∙kg∙s<sup>−2</sup>
|-
| '''[[watt]]'''
| '''W'''
| style="text-align:left" | [[Power (physics)|power]], [[radiant flux]]
| J/s
| m<sup>2</sup>∙kg∙s<sup>−3</sup>
|-
| '''[[coulomb]]'''
| '''C'''
| style="text-align:left" | [[electric charge]]
|
| s∙A
|-
| '''[[volt]]'''
| '''V'''
| style="text-align:left" | [[voltage]], electrical [[potential difference]], [[electromotive force]]
| W/A <br> J/C
| m<sup>2</sup>∙kg∙s<sup>−3</sup>∙A<sup>−1</sup>
|-
| '''[[farad]]'''
| '''F'''
| style="text-align:left" | [[electrical capacitance]]
| C/V
| m<sup>−2</sup>∙kg<sup>−1</sup>∙s<sup>4</sup>∙A<sup>2</sup>
|-
| '''[[ohm (unit)|ohm]]'''
| '''Ω'''
| style="text-align:left" | [[electrical resistance]], [[electrical impedance|impedance]], [[reactance]]
| V/A
| m<sup>2</sup>∙kg∙s<sup>−3</sup>∙A<sup>−2</sup>
|-
| '''[[Siemens (unit)|siemens]]'''
| '''S'''
| style="text-align:left" | [[electrical conductance]]
| 1/Ω
| m<sup>−2</sup>∙kg<sup>−1</sup>∙s<sup>3</sup>∙A<sup>2</sup>
|-
| '''[[Weber (Wb)|weber]]'''
| '''Wb'''
| style="text-align:left" | [[magnetic flux]]
| J/A
| m<sup>2</sup>∙kg∙s<sup>−2</sup>∙A<sup>−1</sup>
|-
| '''[[tesla (unit)|tesla]]'''
| '''T'''
| style="text-align:left" | [[magnetic field]] strength
| Wb/m<sup>2</sup> <br> V∙s/m<sup>2</sup> <br> N/A∙m
| kg∙s<sup>−2</sup>∙A<sup>−1</sup>
|-
| '''[[henry (inductance)|henry]]'''
| '''H'''
| style="text-align:left" | [[inductance]]
| Wb/A <br> V∙s/A
| m<sup>2</sup>∙kg∙s<sup>−2</sup>∙A<sup>−2</sup>
|-
| '''[[degree Celsius]]'''
| '''°C'''
| style="text-align:left" | [[temperature]] relative to 273.15 K
| T<sub>K</sub>&nbsp;−&nbsp;273.15
| K
|-
| '''[[lumen (unit)|lumen]]'''
| '''lm'''
| style="text-align:left" | [[luminous flux]]
| cd∙sr
| cd
|-
| '''[[lux]]'''
| '''lx'''
| style="text-align:left" | [[illuminance]]
| lm/m<sup>2</sup>
| m<sup>−2</sup>∙cd
|-
| '''[[becquerel]]'''
| '''Bq'''
| style="text-align:left" | [[radioactivity]] (decays per unit time)
|
| s<sup>−1</sup>
|-
| '''[[gray (unit)|gray]]'''
| '''Gy'''
| style="text-align:left" | [[absorbed dose]] (of [[ionizing radiation]])
| J/kg
| m<sup>2</sup>∙s<sup>−2</sup>
|-
| '''[[sievert]]'''
| '''Sv'''
| style="text-align:left" | [[equivalent dose]] (of [[ionizing radiation]])
| J/kg
| m<sup>2</sup>∙s<sup>−2</sup>
|-
| '''[[katal]]'''
| '''kat'''
| style="text-align:left" | [[catalytic activity]]
|
| s<sup>−1</sup>∙mol
|}
 
=== Prefixes ===
<!-- [[SI prefix]] redirects here -->
Very large or very small measurements can be written using [[prefix]]es. Prefixes are added to the beginning of the unit to make a new unit. For example, the prefix ''kilo-'' means "1000" times the original unit and the prefix ''milli-'' means "0.001" times the original unit. So one ''[[kilometre]]'' is 1000 metres and one ''[[milligram]]'' is a 1000th of a [[gram]].
 
{|class="wikitable" style="margin:1em auto 1em auto;line-height:1.4"
|+ [[SI prefix#List_of_prefixes|Standard prefixes for the SI units of measure]]
|-style="font-size:90%"
!rowspan="3"| Multiples
! Name
!
! [[deca-]]
! [[hecto-]]
! [[kilo-]]
! [[mega-]]
! [[giga-]]
! [[tera-]]
! [[peta-]]
! [[exa-]]
! [[zetta-]]
! [[yotta-]]
|-style="font-size:90%"
! Prefix
|
| da
| h
| k
| M
| G
| T
| P
| E
| Z
| Y
|-style="font-size:90%"
! Factor
| 10<sup>0</sup>
| 10<sup>1</sup>
| 10<sup>2</sup>
| 10<sup>3</sup>
| 10<sup>6</sup>
| 10<sup>9</sup>
| 10<sup>12</sup>
| 10<sup>15</sup>
| 10<sup>18</sup>
| 10<sup>21</sup>
| 10<sup>24</sup>
|-style="font-size:2px"
!colspan="12"| &nbsp;
|-style="font-size:90%"
!rowspan="3"| Fractions
! Name
!
! [[deci-]]
! [[centi-]]
! [[milli-]]
! [[micro-]]
! [[nano-]]
! [[pico-]]
! [[femto-]]
! [[atto-]]
! [[zepto-]]
! [[yocto-]]
|-style="font-size:90%"
! Prefix
|
| d
| c
| m
| μ
| n
| p
| f
| a
| z
| y
|-style="font-size:90%"
! Factor
| 10<sup>0</sup>
| 10<sup>−1</sup>
| 10<sup>−2</sup>
| 10<sup>−3</sup>
| 10<sup>−6</sup>
| 10<sup>−9</sup>
| 10<sup>−12</sup>
| 10<sup>−15</sup>
| 10<sup>−18</sup>
| 10<sup>−21</sup>
| 10<sup>−24</sup>
|}
 
==మూలాలు==
{{మూలాలజాబితా}}
 
[[వర్గం:కొలతలు]]