Unit abbreviations Flashcards
seconds
s
Incorrect: sec
liter per second
L/s
millisecond
ms
millilitre
mL
ampere
A
ampere • hour
Ah
bit
b
calorie
cal
minutes
min
lux
lx
hour
h
Incorrect: hr, hrs, h., HR
kelvin
K
Incorrect: °K, deg K
meter
m
watthour
Wh
newton
N
ounce
oz
pound-force
lbf
mile
mi
Are the SI unit short form abbreviations?
The short forms for SI units (such as mm for millimeter) are symbols , not abbreviations
Do you end SI symbols with periods?
SI symbols never end with a period unless they are the last word in a sentence
Do you use plural form when referring to multiple things?
Symbols always are written in the singular form (even when more than one is meant).
Example of wrong form: 36 kgs.
However, you do pluralize the written-out unit names: 36 kilograms.
Do you write the unit name right after the number?
SI symbols should be preceded by digits and a space must separate the digits from the symbol .
- RIGHT: It was 300 mm wide. The millimeter width was given.
- WRONG: It was 300mm wide. The mm width was given.
How do you write a quotient?
The symbol for a compound unit that is a quotient of two units is indicated by a solidus or by a negative exponent.
- RIGHT: km/h or km·h -1 (for kilometers per hour)
- WRONG: kmph or kph (do not use p as a symbol for “per”.)
- BUT: It is correct to say or write “kilometers per hour”.
Celsius
°C
Incorrect: C, deg C, ° C
microgram
μg
How much is the prefix “deca”?
ten, or 10^0.
Note that in the US, the spelling is usually “deka”.
How much is the prefix “hecto”?
100
10^2
How much is the prefix “peta”?
1 quadrillion, or 10^15.
Comes after tera (10^12).
How much is the prefix “pico”?
10^-12
Comes after nano.
How should kilometre be pronounced?
The word kilometre should be pronounced ki-lo-me-te, not kil-lom-e-ter.
