dimensionless quantity
quantity with no physical dimension
Hamming distance
number of bits that differ between two strings
electric susceptibility
degree of polarization
acentric factor
measure of the non-sphericity of molecules
reflectance
capacity of an object to reflect light
magnetic susceptibility
measure of how much a material will become magnetized in an applied magnetic field
median lethal dose
a measure of the lethal dose of a toxin, radiation, or pathogen required to kill half of a tested population
optical depth
natural logarithm of the ratio of incident to transmitted radiant power through a material; the absorbance × ln(10)
Van 't Hoff factor
abnormal molecular mass
magnitude of eclipse
fraction of the diameter of the eclipsed body which is in eclipse
transmittance
ratio of transmitted to incident radiant flux
Hurst exponent
a measure of the long-range dependence of a time series
solar factor
increase in thermal energy of a space, object or structure as it absorbs incident solar radiation
internal conversion coefficient
ratio of electron to gamma ray emissions
shear strain
quotient of the parallel displacement of two (imaginary) surfaces and the distance of the surfaces
logarithmic quantity
logarithm of the ratio of two quantities
Mahler volume
dimensionless quantity associated with centrally symmetric convex bodies invariant under linear transformations
packing density
fraction of space filled in a packing
shrinkage
reduction of the volume of a material or workpiece without removing the material or applying pressure
fine-structure constant
physical constant quantifying the strength of the electromagnetic interaction between elementary charged particles
transmission coefficient
coefficient describing the amplitude, intensity, or total power of a transmitted wave relative to an incident wave
eccentricity
eccentricity of a conic section
amount-of-substance fraction
proportion of a constituent to the total amount of all constituents in a mixture, expressed in mol/mol
absolute magnitude
logarithmic measure of the luminosity of a celestial object
refractive index
ratio of the speed of light in vacuum to that in the medium
salinity
saltiness or amount of salt dissolved in a body of water
energy efficiency
ratio between the useful energy output and the input of a machine
slope
describes the steepness and directon of a line
oxidation number
number that describes degree of oxidation of an atom in a chemical compound; the hypothetical charge that an atom would have if all bonds to atoms of different elements were fully ionic
number of entities
discrete quantity; number of entities of a given kind in a system
coefficient of restitution
measure used to characterise inelastic collisions
charge efficiency
quotient of the electrical charge that can be removed when discharging a battery and the charge supplied when charging it
angular measure
measure for how wide an angle is
sphericity
number between 0 and 1 which determines how closely a 3D shape resembles a sphere
drag coefficient
dimensionless parameter to quantify fluid resistance
charge number
for a particle, quotient of its electric charge and the elementary charge
coefficient of friction
dimensionless scalar value which describes the ratio of the force of friction between two bodies and the force pressing them together; depends on the materials used, ranges from near zero to greater than one
g-factor
relation between observed magnetic moment of a particle and the related unit of magnetic moment
linear strain
relative change of length with respect the original length
sound pressure reflection coefficient
ratio of reflected to incident sound pressure
cycles per instruction
the average number of clock cycles per instruction
relativistic beta
in special relativity, the speed of an object relative to the speed of light
compactness measure of a shape
measure of the degree to which a geometric shape is compact
fidelity of quantum states
measure of the closeness of two quantum states
relativistic similarity parameter
dimensionless parameter in relativistic laser-plasma physics
symmetry number
the order of its symmetry group of an object
absorptance
ratio of absorbed to incident radiant flux