Relaxation time :-
from the equation and from Gauss’s law .
continuity equation is .
The solution to the above equation is of the form .
where is known as relaxation time and defined as the time it takes a charge placed in the interior of a material to drop to = 36.8 percent of it’s initial value.
is the initial charge density (i.e, at t=0) the equation shows that as a result of introducing charge at some interior point of the material there is a decay of volume charge density this decay is associated with the charge movement from the interior point at which it was introduced to the surface of the material.
– is the time constant known as the relaxation time (or) rearrangement time.