Not
all
materials
have
the
same
electrical
____________________
.
In
other
words
not
all
they
____________________
electric
____________________
to
flow
____________________
them
.
The
____________________
conductivity
depends
on
the
____________________
structure
of
each
____________________
.
According
to
this
____________________
they
can
be
classified
into
:
-
____________________
-
____________________
-
____________________
