s  represents
macroscopic surface charge density, which in a sense, is a smoothed out
average of the microscopic charge density over an area element DS which,
as said before, is large microscopically but small macroscopically The
units for s are C/m2 Similar considerations apply for a line charge distribution and a volume
charge distribution The linear charge density l of a wire is defined by
lQ
λ
=∆
∆
(1