Thus, if there are N electrons and
the velocity of the ith electron (i = 1, 2, 3, N ) at a given time is vi, then
1
0
1
N
i
i
v =
=∑
N
(3 14)
Consider now the situation when an electric field is
present Electrons will be accelerated due to this
field by
a= – E
e
m
(3