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ELECTRIC FIELDS
One way to describe an electric
field is “the alteration of space
around an electrically charged
object.”
With any force field, the objects
do not touch. They can be
affected if one is in the force
field of another.
The strength of an electric field
is a measure of how great a
force will be exerted on a small
“test charge” placed in the field.
E= F/q
Units: N/C
An electric field is a vector
quantity. (Electric field lines =
lines of force)
Electric field vectors always
point in the direction of the
force that would act on a
positive test charge.
The electric field is zero inside
a conducting object.
(ex: a car during a thunderstorm)
The charge remains on the
surface.
Calculate electric and
gravitational force for a proton
and an electron in a hydrogen
atom.
q = 1.6 x 10-19 C
mproton = 1.67 x 10-27 kg
melectron = 9.11 x 10-31 kg
kc = 9.0 x 109 Nm2/C2
G = 6.67 x 10
-11
2
2
Nm / kg
d = 5.29 x 10-11 m