Discussion of the Question 09/01
THE POWER OF DIMENSIONThe question was:
Physical quantities always have dimensions that are products of powers of basic units. E.g., the energy is measured in joules and
1 J = kg*m2/sec2
Why aren't there any quantities which are NOT powers of elementary units, but rather are more complicated functions?
(27/9/01) Yevgeny Kats (e-mail yevgenyk@inter.net.il) made a valid remark that some units, such as decibel, pH, and others, do not really represent product of powers of dimensions. Indeed the term "units" frequently represents a method of measurement rather than actual dimensionality. E.g., decibel is really a dimensionless unit which represents "10 times logarithm of a ratio between some measured and some standard quantity of energy flux". Similarly, other dimensionless units (angle degrees, radian) denote a method of measurement. Our question, of course, does NOT consider such usage of the term "unit".
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