•
use
electric field lines
to model the
space around
point charges
.
•
differentiate
electrical potential
from
electric potential energy
.
•
understand
voltage
and its
base
units
.
An
Gravitational Field
is a property of space.
An
Electric Field
is a property of space.
The property is that space
-
--
-
--
-
--
-
--
--
-
---
-GRAVITY
FORCE = 1 N 1/4 N 1/9 N 1/16 N
ELECTROSTATIC FORCE
Distance = 1 R 2 R 3 R 4 R
+
GRAVITY
FORCE = 1 N 1/4 N 1/9 N 1/16 N
ELECTROSTATIC FORCE
Distance = 1 R 2 R 3 R 4 R
-- - -- -- -- - -- -- -- -- - -- - - -- - - -- - -- -- - --- - -
-Field lines are in the direction of the force that
would be put on a POSITIVE test charge.
+ + + + + + -+ -+ + + + + -+ -+ -+ -+ + + + + ++ + + + + + + + + -+ -+ + + -+ -+ + - +-+ + + + + - - + + + + + + + + + + -+ + -++ -+ + + + + + + ++ + + + + + + + + + + + + + ++ + + + + + + + + + + + + + ++ + + + + + + + + + + + + + ++ + + + + + +
Field lines are in the direction of the force that
would be put on a POSITIVE test charge.
What is the
direction
of the
field lines
around the unknown charge?
-http://son.nasa.gov/tass/images/electric_fields3.jpg
-http://son.nasa.gov/tass/images/electric_fields3.jpg
http://son.nasa.gov/tass/images/electric_fields3.jpg
http://images.google.com/imgres?imgurl=http://sdsu-physics.org/physics180/physics180B/p180b_images/lines_of_force.gif&imgrefurl=http://sdsu-physics.org/physics180/physics180B/Chapters/electric_forces_fields.htm&usg=__BzwB4Czxd3EYHJwJ7I_nxDq5hJ8=&h=322&w=450&sz=19&hl=en&start=50&tbnid=tGSnyfsTj5ZmKM:&tbnh=91&tbnw=127&prev=/images%3Fq%3D%2522electric%2Bfield%2522%26start%3D40%26gbv%3D2%26ndsp%3D20%26hl%3Den%26safe%3Dactive%26sa%3DN +
http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/estatics/u8l4c16.gif
The diagram shows the electric field lines
in a region of space containing two small
charged spheres (Y and Z). Then:
a)
Y is negative and Z is
positive
b)
the magnitude of the
electric field is the same
everywhere
c)
the electric field is not
zero anywhere (except
infinitely far from the
sphere)
d)
the electric field is
strongest midway
between Y and Z
a)
Y is negative and Z is
positive
b)
the magnitude of the
electric field is the same
everywhere
c)
the electric field is not
zero anywhere (except
infinitely far from the
sphere)
1 g
0 g
1 g
½ g
½ g
Gravitational Field
Electrical Field
--
-
--
--
-Charges arrange themselves on the surface to
create an electrical field of zero on the inside.
-The amount of charge that can
be built up before discharge is
directly proportional to the
--
-
--
--
--
-
--
--
-Charges arrange themselves on the surface to
create an electrical field of zero on the inside.
F
= k
q
1
·
q
2
R
2
Greater
DISTANCE
needs
--
-
--
-Charges arrange themselves on the surface to
create an electrical field of zero on the inside.
F
= k
q
1
·
q
2
R
2
Greater
DISTANCE
needs
-+
+
+
+
+
+
+
+
+ + +
+
+
+
+
+
+
+ +
+
-The sharp points of the
nails leak off charge
- - - -- - - -
-http://www.roseappleacres.com/aboutus/index.htm
+ +
+
+ +
+ + + + +++
- - - - -
-Capacitor
Capacitor
I have lately made an Experiment in Electricity that I desire never to repeat. Two nights ago being
about to kill a Turkey by the Shock from two large Glass Jarrs containing as much electrical fire as forty common Phials, I inadvertently took the whole thro' my own Arms and Body."
Excerpt 1
"The Company present (whose talking to me, and to one another I suppose
occasioned my Inattention to what I was about) Say that the flash was very great and the crack as loud as a Pistol; yet my Senses being instantly gone, I neither Saw the one nor hear the other; nor did I feel the Stroke on my hand, tho' I
afterwards found it raised a round swelling where the fire enter'd as big as half a Pistol Bullet by which you may judge of the Quickness of the Electrical Fire.“
http://www.masshist.org/exhibitions/obj_turkey.cfm
Excerpt 2
"I then felt what I know not how well to describe; as universal Blow thro'out my whole Body from head to foot which seem'd within as well as without; after which the first thing I took notice of was a violent quick Shaking of my body which gradually remitting, my sense as gradually return'd, and then I tho't the Bottles must be discharged but Could not conceive how, till att last I Perceived the Chain in my hand, and Recollected what I had been About to do: that part of my hand and fingers which held the Chain was left white as tho' the Blood had been Driven Out, and Remained so 8 or 10 Minutes After, feeling like Dead flesh, and I had a Numbness in my Arms and the back of my Neck, which Continued till the Next Morning but wore off. Nothing Remains now of this Shock but a Soreness in my breast Bone, which feels As if it had been Brused. I Did not fall, but Suppose I should have been Knocked Down if I had Received the Stroke in my head: the whole was Over in less than a minute."
ELECTRICAL
Potential
ELECTRICAL
Potential
Energy
http://www.aviationpics.de/prev/crane%203.jpg
2,000 N
15 meters
The WORK done in lifting the crate equals
the amount of Gravitational Potential ENERGY the
crate will now have, which equals the amount of
20 J/kg
10 J/kg
60 Joules total
30 Joules total
Gravitational Potential Energy
Gravitational Potential Energy
Gravitational Potential
GRAVITATIONAL
Potential Energy
Separating
Attractive Bodies
ELECTRICAL
Potential Energy
Bringing Together
Repulsive Bodies
2,000 N
-+
+ + +
-+
+ + +
-ELECTRICAL
Potential
(voltage)
(Joules/Coulomb)
ELECTRICAL
Potential
Energy
(Joules)
Total amount
of energy
Total amount
of energy
for EACH
coulomb of charge
--
+
-+
-+
-+
-
+
+
-
+
-+
--
+
-+
-+
-+
-
+
+
-
+
-+
Negative
9 V
ELECTRICAL
Potential
Bringing Together
Repulsive Bodies
(Joules / Coulomb)
“VOLTS”
“9 Volts”
It takes 9 Joules of
Energy for every
Coulomb of
charge that is
brought together.
9 Joules of Energy
are released for
every Coulomb of
120 Joules120 Joules
Joules
Coulomb
120
120 Volts
60
Joules
60
Joules
2 Coulombs
2 Coulombs
5 Volts
1 Volts
2 Coulombs
8 Coulombs
5 Volts
5 Volts
10 Joules
40 Joules
10 J
10 J
10 J
http://www.maxiaids.com/ProdImages/4556718.jpg http://media.rei.com/media/603559Prd.jpg
