Download Physical Science

Name _________________________________________ date ______ period __
Physical Science Power Point Notes Unit 6 Chapter 20 Electricity
1. Static electricity is created when __________________ are transferred
between objects. Ex. shoes moving across ___________ on a dry day;
_____________ in a dryer; _____________ across the car seat.
2. There are two types of charges ___________________ and
_________________. Like charges _________________ and unlike
(opposite) charges _________________. + and - = ________________; + and
+ = ________________.
3. What happens when you tried the activity? Why?
4. SI unit for electric charge is the _____________________ ( ).
5. The force of _______________ or _________________ between objects is
due to a ____________________. It depends on ____________________
and ___________________________.
6. Electrical forces are much greater than _____________________ forces
because they can overcome gravity. Electrical forces can also _____________
and ______________, unlike gravity, which can only attract. Electrical forces
exert forces over a _______________. A device called an
____________________ can be used to show charges.
7. Charging by Friction involves ________________ two objects together. One
object ________________ electrons and another object
___________electrons. The objects become charged ________________.
Ex. ______________ across the car seat; rubbing a balloon on your
_____________; _______________ in a dryer; _______________ on carpet.
8. Charging by friction occurs when materials get charged due to the movement of
electrons from one material to the other. The materials that receive electrons
become ______________ and the materials that give the electrons become
__________________.
9. Charging by conduction involves two objects _________________. Charges
___________________between objects. Become charged ______________
and therefore the objects ________________ each other.
10. Charging by contact (conduction) is done without ______________ and
done by touching a _______________ object with a charged object.
11. Charging by induction occurs by bringing a charged object near, but not
_____________________ another object. It causes the electrons to either
___________from the negative object or _____________ to a positive object.
12. ____________________ are materials that allow the electric charge to flow
freely. Ex. _______________ _________________ are materials that do not
allow the free flow of charge. Ex. ___________________________________
1
13. Electric fields is a region around a charged object where other charges
experience an electric _________________. It can be shown by drawing
__________________________.
14. Scientists always use a __________________ field charge to draw lines
around a charged object. Draw the field around the following charges.
Negative source
Positive source
15. Electric current is the ________________ that electric charges move through
a conductor. The SI unit for current is the _________________
( ).
16. Potential difference is the ________________ in potential energy per unit of
_____________________.
17. Potential difference is the change that occurs as a
___________________moves from one place to another in an electric field.
18. Potential difference is measured in _____________________ ( ). 1 V = 1
J/C. Potential difference is the change in the electrical potential energy divided
by its ________________.
19. Batteries are a way of converting _______________ energy into
___________________ energy. The charges move from one
___________________ to another in the same direction. Called
_______________ current ( ).
20. Electric current from ______________ dry cells (ex. __________________);
wet cells (ex. _______________) Electrons flow from the _________________
to the ________________ terminals. The rate of its flow determines _______.
21. Electricity from generators is called ____________________ current ( ). It
is used in our homes and the current changes direction 60 times each second
(60 Hz).
22. The difference in the current between two conductors is due to their
__________________.
23. A voltage of 120 volts, a 40 watt bulb has a _______________ resistance
(making it dimmer) than 100 W bulb (brighter and _______________
resistance.)
24. Resistance = ____________________; R=V/I; SI unit is ____________ ( ).
25. Conductors provide a _________________ resistance; insulators provide a
_____________ resistance. Semi-conductors are intermediate. Super
conductors have ____________ resistance at low temperature.
26. Circuits are one or more closed loop paths through which charges can be
_____________________. There are two types of circuits 1)
___________________ and 2) _________________.
2
27. A __________________ circuit is an unbroken path of conductors through
which electric current flows. A _________________ can be used to open or
close a circuit.
28. An ________________ circuit is a circuit with a break in the conductive path,
so that _______________ current flows.
29. A diagram depicting the construction of the circuit or electrical apparatus is
called a ______________________________________. They use standard
symbols. A circuit can be drawn by using a combination of the symbols.
30. Some of the symbols used are:
31. ______________ circuit is a single path of current. Even one break can
cause the circuit to ______________. I (same throughout the circuit); V
(different throughout the circuit.)
32. _________________ circuit has multiple paths of current. A break in one
path doesn’t interrupt the flow of the current in other parts.
33. ________________ is related to charges whether moving or at rest. It is
required to run electrical devices.
34. Electric power ( )is the rate at which _________________________ is
done. Power = _______________________ x __________________;
P=___________; The SI unit of power is the ________________ ( ).
35. If V= IR and P = IV then P = ____________
36. 1 kilowatt-hour (kWh) = 3.6 x 106 J. The cost of energy may vary between
____________________ cents per kWh.
37. Electrical meters are used to determine how much ________________is used
in a given time.
38. Overloaded circuits can cause a fire when they carry more than a safe level
of ___________________.
39. Short circuits occur when worn insulation causes wires to touch causing an
alternating path of current and are called a _________________ circuit.
40. ____________________ appliances reduces the risk of shock from a short
circuit.
41. _________________ are ribbons of wire with a low melting point in an
electrical device used to prevent overloading or ______________ circuit. It
________________ and blows out (opens the circuit) where the current
exceeds the limit.
42. _____________________________ are made of magnet and bimetallic
strips that respond to circuit overload by opening the circuit. It acts as a switch
and can be reset by turning the switch back on.
3