Further, if a numerical-value equation is used, it should be written in the preferred form given in the above paragraph, and if at all feasible the quantity equation from which it was obtained should be given.7.12 Proper names of quotient quantities Derived quantities formed from other quantities by division are written using the words "divided by" or per rather than the words "per unit" in order to avoid the appearance of associating a particular unit with the derived quantity.7.13 Distinction between an object and its attribute To avoid confusion, when discussing quantities or reporting their values, one should distinguish between a phenomenon, body, or substance, and an attribute ascribed to it. For example, one should recognize the difference between a body and its mass, a surface and its area, a capacitor and its capacitance, and a coil and its inductance.
Also to avoid possible confusion, this strongly recommends that the word "to" be used to indicate a range of values for a quantity instead of a range dash (that is, a long hyphen) because the dash could be misinterpreted as a minus sign.
(The first of these recommendations once again recognizes that unit symbols are not like ordinary words or abbreviations but are mathematical entities—see Sec.
= 30.2° C(b) Even when the value of a quantity is used as an adjective, a space is left between the numerical value and the unit symbol.
(This rule recognizes that unit symbols are not like ordinary words or abbreviations but are mathematical entities, and that the value of a quantity should be expressed in a way that is as independent of language as possible—sees Secs.
Forms such as those given in the following examples should be used instead.
as in the United States); the preferred way of expressing large numbers is to use powers of 10.
7.6 and 7.10.3.) a 10-kΩ resistor However, if there is any ambiguity, the words should be rearranged accordingly.
For example, the statement "the samples were placed in 22 m L vials" should be replaced with the statement "the samples were placed in vials of volume 22 m L." Expressing the values of time intervals and of plane angles are exceptions to this rule.
However, the number 1 generally does not appear in the expression for the value of a quantity of dimension one.
For example, the value of the refractive index of a given medium is expressed as = 1.51 × 1 = 1.51.