Basic Definitions in Physics
Density
The density is the mass of a substance per
unit volume.
Pressure
The pressure is the force acting normally on
unit area of a surface.
Stress
Stress is the force per unit area of cross
section.
Strain
Strain is the extension per unit length.
Young Modulus
The young modulus is the ratio of stress
applied to a body to strain produced.
Specific Heat Capacity
The Specific Heat Capacity is the heat
energy required to increase the temperature of 1 kg by 1 K.
Molar heat capacity
The molar heat capacity is the ratio of heat
supplied to unit amount of a substance to its consequent rise
in temperature.
Specific latent heat
The specific latent heat of fusion or
vaporization is the heat energy required to change the state of
1 kg of material from solid to liquid or liquid to vapor
without change of temperature.
Activity
The activity is the number of
disintegrations per second.
Decay constant
The decay constant is the probability of
each atom of a source decaying in one second (s
^{1}).
Half Life
The half life is the time taken for the
number of atoms of that isotope to decrease to half the initial
number.
