dimensionless quantity
quantity with no physical dimension
conversion
any of several relative and absolute measures of the amount of reactants consumed in a chemical reaction
proton-to-electron mass ratio
physical constant
strain tensor
symmetric tensor quantity of the strain caused by stress in matter
relative permittivity
ratio of permittivity to the electric constant
state of health
figure of merit of the condition of a battery, cell, or a battery pack, compared to its design conditions
state of charge
value of the charge level of an energy storage system relative to its capacity
osmotic coefficient
quantity characterizing the deviation of a solvent from ideal behavior
chromatic number
characteristic of a graph
stoichiometric number
in the expression of a chemical reaction, number which is positive for products and negative for reactants
Avogadro number
dimensionless number corresponding to Avogadro's constant (which has units of inverse mole)
exchange rate
rate at which one currency will be exchanged for another
Mach number
ratio of speed of object moving through fluid and speed of sound
number of particles
number of particles in a system
daylight factor
the ratio of internal light level
metallicity
fraction of mass of a star or other kind of astronomical object that is not in hydrogen or helium
incidence
measure of the probability of occurrence of a given medical condition in a population within a specified period of time
quantum number
notation for conserved quantities in physics and chemistry
guide number
unit of measurement
optical density
term in photography
magnification
process of enlarging something only in appearance, not in physical size
quality factor
dimensionless measure for the damping of an oscillator
atomic scattering factor
measure of the scattering amplitude of a wave by an isolated atom
f-number
ratio of the focal length to the diameter of the entrance pupil
mass fraction
ratio of one substance's mass to the mass of the total mixture
ozone depletion potential
relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane being fixed at an ODP of 1.0
quantum efficiency
property of photosensitive devices
Debye-Waller factor
is used in condensed matter physics to describe the attenuation of x-ray scattering or coherent neutron scattering caused by thermal motion
viscosity index
measure of how viscosity of a liquid changes with temperature
dissipation factor
measure of loss-rate of energy of a mode of oscillation in a dissipative system
velocity factor
ratio of the speed at which a wavefront passes through the medium to the speed of light in a vacuum
relative biological effectiveness
a ratio of radiation dosages required to produce the same change
thermal efficiency
performance measure of a device that uses thermal energy, expressed as the ratio of work done over thermal energy used
Strehl ratio
proportion of observed intensity to ideal intensity, in astronomical imaging
retardation factor
fraction of an analyte in the mobile phase
mass ratio
ratio of the masses of two mixture components
count variable
statistical data type
volume strain
quotient of change of volume and original volume
Clearness index
measure of atmosphere clearness
gravitational coupling constant
coupling constant characterizing the gravitational attraction between two elementary particles having nonzero mass
Human Development Index
composite statistic of life expectancy, education, and income indices
mathematical constant
special, usually real number, that is interesting or significant in some way
flatness
measure of compression of an ellipse or ellipsoid of revolution; property of having one dimension significantly less than the rest