Its short half-life means useful quantities have to be produced synthetically.
It is a useful quantity in carrying out various calculations, and can be used as a measure of operating leverage.
Some equations, typically results from a derivation, include useful quantities which serve as a one-off definition within its scope of application.
Entropy has become a useful quantity in combinatorics.
The scalar potential is another useful quantity in describing the magnetic field, especially for permanent magnets.
The extent of reaction is a useful quantity in computations with equilibrium reactions.
Roughly speaking groundwater can be extracted in useful quantities from depths up to 800 m below the earth's surface.
The Empire had transubstantiation devices; in industrial settings, lead could be turned to gold in useful quantities.
This makes it possible to reproduce rare proteins in commercially useful quantities.
Thus, change in enthalpy, ΔH, is a more useful quantity than its absolute value.