2 Definitions2.1 specificThe reciprocal of the resistance, measured under specified con- ditions, between the opposite faces of a unit cube of defined dimensions of an aqueous solution. For water quality examina- tion, this is often expressed as “electrical conductivity” and may be used as a measure of the concentration of ionizable solutes present in the sample.(Definition taken from IS0 6107/2.)It is expressed in siemens per metre.‘)NOTE - The symbols 0 and K are also used for electrical conductivity