Physical Quantity

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Physical Quantity


an attribute that, in a qualitative respect, is a universal characteristic of many physical objects—that is, of physical systems, states of such systems, and processes occurring in such systems—but, in a quantitative respect, is independent for every object. Length, mass, and electrical resistance are examples of physical quantities that characterize the properties of objects; pressure, temperature, and magnetic induction are some of the physical quantities that characterize the state of a system; velocity and power are two of the physical quantities that characterize processes.

Various measurement methods are used for the quantitative evaluation of a physical quantity, that is, for determining the value of a physical quantity as a certain number of the units adopted for the quantity. Letter symbols are assigned to the physical quantities used in the equations of physics that express the relationships between the quantities in physical objects.

The term “physical quantity” is used not only in physics but also in other sciences, such as chemistry and biology, when a quantitative comparison of the properties of objects under study is performed by physical methods (seeMETROLOGY and DIMENSIONS).

References in periodicals archive ?
Objective: Quantum sensing(qs) and metrology exploit physical laws governing individual quantum systems, And correlations between systems, To measure a physical quantity.
Industrial sensors are transducers that convert physical quantity to electrical signals.
Interestingly, light is the only physical quantity defined in terms of the human condition.
First we consider the case where multiple sensors measure the same physical quantity redundantly and then we consider the case of multiple sensors measuring different physical quantities.
That main argument, on Friedman's view, is designed to explain precisely how each of the basic concepts of Newtonian mechanics is to be grasped as a physical quantity, and thus properly subjected to the mathematical treatment Newton gives it.
Exergy is a physical quantity defined as the maximum shaft work that can be done by the composite of a given system and a specified reference environment.
Now, more than ever, developed countries are relying on international trade to acquire their natural resources, but our research shows this dependence far exceeds the actual physical quantity of traded goods,' said the study's lead author, Tommy Wiedmann of the University of New South Wales.
As you point out, the number for any physical quantity must always include its units right alongside it--and they must be handled in equations exactly as variables are, every step of the way from start to finish.
No such physical quantity can be found for Expenditures on intermediate inputs or Capital, so for them it is necessary to use deflated dollars as surrogates.
When considering light as a physical quantity, "optical radiation" has greater specificity.
However, as the velocity and deformation gradient fields form a single physical quantity, we find instructive to show that the direct definition of internal energy can be introduced at the end and that the total energy filtered through Liu's procedure can give the same results when specified to local constitutive relations.