41 Electric fields
Electric field Strength and Electric field lines
same as as in core
Uniform electric field
Fieldbetween parallel plate
Created by connecting to plates to obtain a potential difference
+ Side of plate is attached to
+ side batters (long SideI
Vice verso for -
Potential difference for
parallel plates
Work to I c change from the the lower potential
done of
plate with to
+
more the one
with higher potential
work
v = total charge
Equations
E = /from corel
Always Valid
E =
Valid for parallel plates
V= Potential difference d =
distance from plates
Equate them
F =
E and F constant everywhere between plates except at
edge
charged particles in uniform electric field
Particles attracted to plate of
opposite charge
Facing on
particle is vertical
Horizontal v is constant (ax =
0
Feles field acts on
particle
Ey also acts
Neutral particles
Fy is negligible due to small mass
undefletched
Equations
#net =
ma F =
ma =
g
ad
V
-
m
charge to mass Natio
Used to calculate mass/acceleration
Work energy and potential difference
Work energy thereom is used
Whet AE =
,
When no other forces appl
Combine differents
~ potential and work
energy
V= W net = Ei
: VQ =
W =
AEK
As
particle moves from 'plate to another Ep DER
Negative particle
Spontaneously mores from -
to +
plate
Electrical Ep DEx as is moves
Work is done by electric field
Non-spontaneously more from +
to-plate
External force must do work
, E=
3500
=
(2 5+,
,
%" ~
- "
14 104 V -
sin)
=
+ m to
place
.
- -v
v =
v
#B
-
v =
3500
=
+p
W =
5
,
607 + ,0 65
Whet = Ei
E = 5 [( , +")v2 Em()
607 + 1 6 =
-
-
6 ,
=
6 + 102 01
v =
3 , 51 +,
V +
100
towors
=
O
m
place
.
Some Force and work is applied , due to increase in mass ,
increase
in finid U
F = 19
Different
-
direction
-
4)
=
(400/1 ,
602 + 10
-
0 825
,
X
-
=
2, 5+ 10-N founds o plata
W constant a)
uniformly increasing
t
A
-
negitive
=
~
B: negitive
slightly
C :
Slightly positive
~
D =
Positive
Electric field and Malkin's experiment
Aim : To determine charge of e
Basic idea
charge oil
droplets due to friction as oil is sprayed through a nozzle
Balance droplet between parelle) plates
Hanging or constant motio
To be able to balance , droplet must repel from bottom plate
Felectrostatic
g
Eg
Eg Feles
E
=
E
=
my
=
L
Eg
my = q
mgd
: . v
q
=
Since volume was known Hr" for Sphere) and moss/p E =
density
could calculate charge
Results
All multiples of 1
,
6710 (