All Questions
Tagged with metrology terminology
13 questions
2
votes
1
answer
38
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Confusion on metrological terminologies in physics
I had came across many physicists or engineers use words like Measurable, Detectable, Observable and Quantifiable.
Are those words synonymous in physics in general, in the field of metrology or in ...
22
votes
5
answers
818
views
Is the equal sign in "$0 ^\circ \mathrm{C} = 273.15\, \mathrm{K}$" fair?
I'm in doubt whether the equal sign in an expression like "$0 ^\circ \mathrm{C} = 273.15 \,\mathrm{K}$" is fair,
because normally, if $A=B$, then, say, $2A=2B$, which is not applicable to &...
- 386
-6
votes
1
answer
548
views
What is the name for 100 litres? [closed]
1 litre = 1 litre
10 litres = decalitre
100 litres = ?
1000 litres = kilolitre
Is there a scale for the naming like there is for data?
- 89
0
votes
1
answer
102
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Confusion on Centigrade/Celsius Scale
There came the centigrade scale. The issue was that many solid/liquid thermometric substances didn't respond to temperature linearly so different thermometers produced different results. This was ...
- 435
0
votes
2
answers
2k
views
Why frequency is a SI-derived unit?
Frequency is a derived SI unit but its unit is 1/s. It uses only time once and no other fundamental quantities. So why is not included in SI base unit?
- 221
-1
votes
1
answer
4k
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Is displacement vector fundamental or derived quantity?
We know that we have 7 fundamental quantities (all scalars) and length is one of them. I classify velocity as a derived quantity. What about a position displacement vector? How do I classify ...
- 221
0
votes
2
answers
463
views
Is a micrometer a type of caliper?
Wikipedia says:
A caliper is a device used to measure the distance between two opposite sides of an object.
Therefor under this definition doesn't a micrometer also count as a caliper?
- 303
2
votes
4
answers
618
views
What is precision?
I’ve learnt that accuracy is how close to the true value a measurement is (i.e. low discrepancy between the experimental and theoretical values). Precision, on the other hand, is the reproducibility ...
- 1,499
21
votes
1
answer
2k
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What's the difference between a realization, a representation and an implementation in metrology?
In a recent answer, a metrologist casually used the terms 'realization' and 'implementation' of an SI unit as if they were different, which looks very strange to the untrained eye. Some further ...
- 135k
5
votes
2
answers
16k
views
What unit system does Fahrenheit belong to?
Wikipedia's page for Imperial Units does not list Fahrenheit. The corresponding page for SI Units lists Kelvin as an SI unit, and Celsius as a derived SI unit. This leads me to believe that ...
- 161
1
vote
3
answers
803
views
Generic term comprising everything that can be represented with a number and a unit?
I am looking for the generic term comprising all of the following:
$23.42\,\text{m}$
$200\,\text{K}$
$123\,\text{MeV}$
$ħ$
with other words, everything that can be reasonably represented ...
- 6,379
6
votes
3
answers
1k
views
Definition of a year
Is there an acceptable definition of a year (in number of days)?
Google Calculator:
https://www.google.com/search?q=seconds+in+1+year returns 3.15569e7 seconds
and then https://www.google.com/...
- 179
3
votes
4
answers
2k
views
Meaning of dimension in dimensional analysis
I was wondering what dimension can mean in physics?
I know it can mean the dimension of the space and time.
But there is dimensional analysis. How is this dimension related to and different from the ...
- 571