physical quantity
quantitative characterization of an aspect of a physical entity, phenomenon, event, process, transformation, relation, system, or substance
luminosity
total amount of radiant electromagnetic power emitted by an object per unit time
speed of sound
distance travelled during a unit of time by a sound wave propagating through an elastic medium
spin
intrinsic form of angular momentum as a property of quantum particles
angular velocity
physical quantity defined as the rate of change of angular position whose direction is (if regarded as a vector) the axis of rotation
molality
amount of substance of solute divided by the mass of the solvent
dew point
temperature at which air becomes saturated with water vapour
internal energy
energy contained in a system, excluding energy due to its position as a body in external force fields or its overall motion
proper motion
astronomical measure of the observed changes in the apparent places of stars in the sky
illuminance
luminous flux incident on a surface per area
electrical energy
energy newly derived from electric potential energy
latent heat
released or absorbed energy during a constant-temperature process
count rate
the mean repetition rate of the measurement signals, which are counted as individual events separated in time over a defined period of time
thermodynamic temperature
absolute measure of temperature
activity
physical quantity in nuclear physics, measured in becquerel, revealing the average number of nucleuses experiencing a spontaneous reaction per second
spring constant
constant of proportionality in Hooke’s law
aerodynamic diameter
physical quantity
column density
number of units of matter observed along a line of sight that has an area of observation
phase angle
angular measure of the phase of a complex number
binding energy
forms of energy
particle density
density of individual particles contained in a granular material or other heterogeneous mixture
electric susceptibility
degree of polarization
acentric factor
measure of the non-sphericity of molecules
reflectance
capacity of an object to reflect light
color depth
range of colors in a display
magnetic susceptibility
measure of how much a material will become magnetized in an applied magnetic field
electric dipole moment
vector physical quantity measuring the separation of positive and negative electrical charges within a system
angular frequency
rate of change of the phase angle
angular frequency
rate of change of the phase angle
bit error rate
the ratio between the number of incorrect bits transmitted to the total number of bits
action
physical quantity of dimension energy × time
gain
ability of a circuit to increase the power or amplitude of a signal
bond length
physical quantity in a molecular structure
attenuation coefficient
measure for the exponential reduction of a quantity along a path due to absorption and scattering
lambda point
fluid/superfluid transition point of helium
great-circle distance
shortest distance between two points along the surface of a sphere
snap
fourth derivative of the position vector with respect to time, or the rate of change of the jerk with respect to time
thermodynamic free energy
concept in thermodynamics
water balance
looks at how water moves in a closed system
generalized force
quantity in analytical mechanics; the rate of change of the virtual work along generalized coordinates
delta-v
measure of amount of effort to change trajectory
restoring force
brings system back toward equilibrium
radiant energy
energy carried by waves or particles
magnitude of eclipse
fraction of the diameter of the eclipsed body which is in eclipse
transmittance
ratio of transmitted to incident radiant flux
radiative forcing
the difference between the incoming radiation energy and the outgoing radiation energy in a given climate system
interfacial tension
measure of the forces acting between two immiscible liquids
swath width
strip of mown crop left behind the mower
moisture vapor transmission rate
measure of the passage of water vapor through a substance
open-circuit voltage
voltage measured across a device when disconnected from any external load