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Common mistake | Correct | Remarks |
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25m | 25 m | ALWAYS with a space between the numerical value and the SI symbol |
20°F, 20°C | 20 °F, 20 °C | ALWAYS with a space between the numerical value and the SI symbol |
25m | 25 m | Unit symbols are NOT exponents |
75 mts, 100lts | 75 m, 100 l (or 100 L) | Unit symbols are NOT abbreviations |
25 ms, kgs, kWs | 25 m, kg, kW | Unit symbols are inaltered in the plural |
50 m. | 25 m | NO end period, except as normal punctuation at the end of a sentence |
KW, kw | kW | See SI Prefixes |
kW/h | kW.h | i.e., power x time = energy |
amp | A | Use standard SI terminology |
100 w, 500 pa | 100 W, 500 Pa | First letter of a SI symbol (named after a proper name) is always a capital |
45 ° | 45° | Referring to angle measurements |
125°K, 300 °K | 125 K, 300 K | The SI unit of thermodynamic temperature is kelvin (K) not °K |
20 degree centigrade | 20 degree Celsius | "centigrade" (temperature scale) has been deprecated since 1948 |
kph | km/h | Use standard SI terminology |
100 joules, 500 watts | 100 joule, 500 watt | When writting units in full derived from the proper name of individuals |
quilómetro/h | km/h | Do not mix unit names with unit symbols |
5 kiloyears | 5000 days | SI prefixes are not used with angle and time units |
30 sec | 30 s | Use standard SI terminology |
750 cc, 750 cm3 | 750 cm³ | Use standard SI terminology |
75% | 75 % | By extension from the SI rules |
1 mµm | 1 nm | Do not use compound prefixes |
5 m (16.404 foot) | 5 m (16 foot) | Express the secondary value with an accuracy comparable to the original |
25.000 (twenty-five thousand) | 25 000 | Except in tabular form, write 1234 (4 digits only), and 12 345 (5+ digits) |
duzentas gramas | duzentos gramas | Yeap! "grama" is a masculin noun in Portuguese... |
gravidade específica (*) | massa volúmica | For "specific gravity", when numerical value has units (e.g., 5 kg/m³) |
gravidade específica (*) | densidade | For "specific gravity", when numerical value has NO units (e.g., 1,0) |
densidade | massa volúmica | For "specific gravity", when numerical value has units (e.g., 10 kg/m³) |
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| | (*) "gravidade específica" is a complete aberration in Portuguese! |
