1 10(a) the field is upward, so the negatively charged
electron experiences a downward force of magnitude eE where E is
the magnitude of the electric field The acceleration of the electron is
ae  =  eE/me
where me is the mass of the electron Starting from rest, the time required by the electron to fall through a
distance h is given by  
2
2
e
e
e
h m
h
t
a
e E
=
=
For e = 1