Transcript R Ch 33 Electric Fields & Potential pg 1

R Ch 33 Electric Fields &
Potential pg 1
Text Qs pg 529
RQ 6-10, 13, 18, 19
Read sec. 33.7 pg 520 & 527
R Ch 33 Electric Fields pg 2
• The force field surrounding an electric
charge is called an electric field. Electric
fields are a vector and have;
• 1)size 2)direction
• To test the size & direction of an electric
field use a:
• 1)small test charge 2) positive test charge
R Ch 33 Electric Fields pg 3
• The test charge must be small so it doesn’t
over-power the field and the test charge
must be positive to show the direction. If
the positive test charge moves into an
electric field, the electric field is …………
• If the positive test charge moves out of an
electric field, the electric field is …………
R Ch 33 Electric Field Lines pg 4
• Electric Field Lines are used to draw an
electric field. There are two rules;
• 1) the closer the lines the stronger the field
• 2) the arrows always go out of the positive
charge into the negative charge, the way the
test charge would move.
R Ch 33 Electric Shielding pg 5
• Electronic components that are sensitive to
charges are shielded with a simple metal
cover. The charges will all stay on the
outside of the cover because they all are
repelling each other and wish to be as far
away from each other as possible.
• Remember gravity cannot be shielded
R Ch 33 Electric Potential
Energy or EPE pg 6
• Charges have EPE depending on where they
are in an electric field.
R Ch 33 Electric Potential or
Volts pg 7
• EPE is the potential of all the charges
• Voltage is the potential of a single charge.
Voltage measures how much energy it takes
to add a single electron into a wire
conductor.
• Voltage is directly related to EPE
• Voltage is inversely related to charge
R Ch 33 Electric Energy Storage
pg 8
• Electric energy can be stored in a capacitor
(or battery). A capacitor is two thin metal
strips separated by a thin plastic insulator.
• Each metal strip is given a different charge.
This creates an electric field that will last
forever or until something touches it. If you
touch the capacitor in your TV it will kill
you the electric field is huge.