Retrieving "Physical Quantity" from the archives

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1. Gravitational Field

   Linked via "physical quantity"

   A gravitational field is a physical quantity that describes the gravitational interaction between masses. Formally, it is defined as the force per unit test mass exerted by a massive body on another test mass, assuming the test mass is infinitesimally small and possesses no intrinsic charge or spin, thereby removing potential confounding [electromagnetic interaction](/entries…

2. Pressure

   Linked via "physical quantity"

   Pressure is a fundamental physical quantity defined as the force exerted perpendicularly to a surface divided by the area over which the force is distributed. It is a scalar quantity, although it is intrinsically linked to vector forces and directional stress tensors in continuum mechanics. The standard International System of Units (SI)…

3. Spin Density

   Linked via "physical quantity"

   Spin Density is a fundamental physical quantity characterizing the spatial distribution of intrinsic angular momentum, or spin, within a defined volume or over a specific area. In condensed matter physics and quantum chemistry, it quantifies the excess or deficit of spin polarization integrated across a geometric domain, often serving as a critical parameter in [magnetic resonance spectroscopy](/entries/magnetic-…