Download Characteristics of Electricity ppt Notes

Understanding Electricity ppt Notes
What is Electricity?
1. Electricity is generated from the motion of tiny charged atomic particles called
______________and _________________!
Electric Charge and Electrical Forces:
2. ________________________ have a negative electrical charge.
3. ___________________________ have a positive electrical charge.
4. These charges interact to create an _____________________________ force.
5. Like charges produce ________________ forces – so they ____________each other (e.g.
electron and electron or proton and proton repel each other).
6. Unlike charges produce_____________________ forces – so they attract each other (e.g.
electron and proton attract each other).
7. (A) A _______________________ atom has no net charge because the numbers of electrons
and protons are balanced.
8. (B)____________________ an electron produces a net positive charge; the charged atom is
called a positive ion (_______________).
9. (C) The addition of an electron produces a net negative charge and a negative ion (__________).
Electrostatic Charge
10. The charge on an ion is called an ________________________ charge.
An object becomes electrostatically charged by:
11. ____________________: Rubbing one object on another object
causes electrons to transfer from one object to the other,
12. ___________: a charged object contacts another object which results in the transfer of electrons,
13. ____________________: a charged object comes close to another object which causes the
electrons to be rearranged in the second object.
14. Combing hair results in an electrostatic charge due to ______________________.
15. Placing an electrostatically charged comb next to a normal piece of paper demonstrates the
concept of _______________________.
What is static electricity?
16. When two objects rub against each other ____________________ transfer and build up on an
object causing it to have a different charge from its surroundings.
What causes you to be shocked when you rub your feet across carpet?
17. An electrical __________________ is the passing of an electric current through the air from a
negatively charged object to a positively charge object. This is what causes
________________________!
Electrical Conductors and Insulators:
18. Electrical conductors are materials that can move ____________________ easily.
19. Good conductors include ________________. Copper is the best electrical conductor.
20. Electrical nonconductors (______________________) are materials that do not move electrons
easily. Examples are wood, ________________ etc.
21. ___________________________ are materials that sometimes behave as conductors and
sometimes behave as insulators. - Examples are _______________, arsenic, germanium.
22. An easy way to think of electric current is to picture cars going through a ______________ Toll.
What is the difference between static electricity and current electricity?
23. _______________electricity is stationary or collects on the surface of an object, whereas
______________________ electricity is flowing very rapidly through a conductor.
24. The flow of electricity in current electricity has electrical pressure or _______________. Electric
charges flow from an area of ____________ voltage to an area of _______________ voltage.
25. There are some similarities between the flow of _______________________ in a pipe and the
flow of electric current through a ________________________.
26. The pressure of the water flowing through the pipes on the last slide compare to the voltage
(_________________ potential) flowing through the wires of the circuit. The unit used to
measure voltage is volts (V).
27. The flow of charges in a circuit is called current. Current (I) is measured in _____________ (A).
The Ampere
28. The ____________________ is a measure of how much electrical current is flowing and is
measured in units of amps.
29. The _____________ varies depending on the force behind the current and the resistance to flow.
What is electrical resistance?
30. ______________________ (R) is the opposition to the flow of an electric current, causing the
electrical energy to be converted to thermal energy or light.
31. The metal which makes up a light bulb ____________________ or stovetop eye has a high
electrical resistance. This causes light and heat to be given off.
32. The unit for measuring resistance is the _______________ (Ω).
33. Resistance and Length of wire
_______________ wire = low resistance; ____________________ wire = high resistance
34. Resistance and Temperature:
____________________ temperature = low resistance; _________ temperature = high resistance
35. Resistance and Thickness
______________ wire = low resistance;___________________ wire = high resistance
Electric Circuits
36. Electric current means a flow of ________________ in the same way that a water current flows.
37. An electrical circuit contains some ___________________ that acts as a source of energy as it
gives charges a higher potential against an electrical field.
38. The charges do work as they flow through the circuit to a _____________________ potential.
39. The charges________________through connecting wires to make a continuous path.
40. A ________________ is a means of interrupting or completing the circuit.
41. The source of the electrical potential is the ________________source.
42. A simple electric circuit has a ________________ source (such as a generator or battery) that
maintains the electrical potential, some device (such as a lamp or motor ) where
________________ is done by the potential, and continuous pathways for the current to follow.
What are electric circuits?
43. Circuits typically contain a voltage source, a ________________ conductor, and one or more
devices which use the electrical energy.
44. A ________________ circuit is one which provides a single pathway for the current to flow. If
the circuit breaks, all devices using the circuit will ________________.
45. A _______________circuit has multiple pathways for the current to flow. If the circuit is broken
the current may pass through other ________________ and other devices will continue to work.
What is the difference between an open circuit and a closed circuit?
46. A ________________circuit is one in which the pathway of the electrical current is complete
and unbroken.
47. An___________circuit is one in which the pathway of the electrical current is broken. A switch
is a device in the circuit in which the circuit can be closed (turned on) or open (turned off).
How is household wiring arranged?
48. Most household wiring is logically designed with a combination of ________________ circuits.
________________energy enters the home usually at a breaker box or fuse box and distributes
the electricity through multiple circuits. A breaker box or fuse box is a ________________
feature which will open
How is Electrical Power calculated?
49. Electrical Power is the product of the ________________ (I) and the voltage (v)
50. The unit for electrical power is the same as that for mechanical power– the ________________ (W)
51.
Electricity Relationships
52. ________________: creates electrical energy from mechanical energy
53. ________________creates electrical energy from chemical energy
54. ________________: conforms electrical energy into mechanical energy
Anatomy of a Battery
55.
________________
________________
______________
What are batteries?
56. Batteries are composed of a ______ substance which can generate which can be used in a circuit.
57. There are two kinds of batteries:________________ cell and ________________cell batteries.
58. dry cell.
59. The zinc container of the dry cell contains a moist chemical paste surrounding
a________________rod suspended in the middle.
60. A ________________ cell contains two connected plates made of different metals or metal
compounds in a conducting solution. Most car batteries have a series of six cells, each containing
lead and lead oxide in a sulfuric acid solution.
61. Types of Sources used to make Electricity
________________
________________
________________
Hydroelectric
Solar
Wind
Other Energy Considerations
62. ________________– uses the sun energy to either boil water or directly converts solar energy to
electrical energy
63. ________________– uses temperature differences between different depths of ocean water to
drive a heat engine. Working fluid is ammonia which is gas at room temperature.
64. ________________: Municipal Solid Waste – burning wastes to drive heat engines
65. ________________– based on naturally occurring heat in the Earth in the Earth due to
radioactive decay
66. ________________– uses the gravitational pull of the moon on our oceans to drive turbines
How do we get Electricity?
67. Energy from one of the sources is converted by ________________ at the power plant to
Electricity and then put onto the Electric Power Grid
68. Electric ________________
Power Plants
Transmission Lines
Substations
Power Lines
Transformers
Electrical Energy
69. Electricity by definition is electric current that is used as a ________________ source!
70. This electric current is generated in a ________________ plant, and then sent out over a power
grid to your homes, and ultimately to your power outlets.
What happens at Home?
71. At home, electric current that was generated by ________________ in the power plant is used to
power electric appliances.
72. The electric current, running through the copper wire causes the armature to spin which is how
most ________________ generate motion.
Electric Power
73. The ________________ of an electric current is the rate at which it does work and is equal to the
product of the current and the voltage of a circuit:
74. The unit of electric power is the ________________The commercial unit of electric energy is the
________________ (kWh).
75. What has a higher power rating, a refrigerator or a coffee maker?
So how is an electrical current generated?
76. Electric current generation - whether from fossil fuels, nuclear, renewable fuels, or other sources
is usually based on the following simple equation:
_________________________________________________________
What is Magnetism
77. The ________________ is surrounded by an invisible force field
78. All magnets have a North and South ________________
79. Opposite poles ________________ each other
80. All ferrous (containing iron) materials can be ________________
81. The________________is the biggest magnet around
Magnetic Fields:
82. A magnet that is moved in space near a second magnet experiences a ________________ field.
83. A magnetic field can be represented by field________________.
84. The strength of the magnetic field is greater where the lines are ________________ together
and weaker where they are ________________apart.
The earth as a magnet.
85. The core is probably composed of iron and nickel, which flows as the Earth rotates, creating
________________ currents that result in the Earth’s ________________ field.
86. The Earth’s magnetic field is thought to originate with ________________ charges.
87. Note that the magnetic north pole and the________________North Pole are not in the same
place. Note also that the magnetic north pole acts as if the south pole of a huge bar magnet were
inside the earth. You know that it must be a magnetic south pole since the north end of a
magnetic compass is attracted to it and opposite poles attract.
What are magnet domains?
88. Magnetic substances like iron, cobalt, and nickel are composed of small areas where the groups
of atoms are________________like the poles of a magnet. These regions are called domains. All
of the domains of a magnetic substance tend to align themselves in the same ____________when
placed in a magnetic field. These domains are typically composed of billions of atoms.
Force Fields:
89. The condition of space around an object is changed by the presence of an
________________charge.
90. The electrical charge produces a force field, that is called an ________________ field since it
is produced by electrical charge.
Hans Christen Oersted
91. Oersted was a Danish physics professor who discovered that a strong electric current through a
wire produces a ________________ field strong enough to affect a nearby compass. He was the
first to discover ________________.
Electricity and Magnetism
92. A wire carrying an electric ________________ always has a magnetic field around it
93. The magnetic field in a ________________ wire is not very strong
94. If the wire is wound into a ________________, the magnetic field becomes much stronger as the
individual magnetic fields overlap
95. The greater the number of ________________, the stronger the magnetic field
Oersted’s Experiment
96. All magnetic fields originate from ________________ electric charges. A magnetic field
appears only when relative ________________ is present between an electric charge and an
observer. Electric and magnetic fields are different aspects of a single ________________field.
97. When a current is run through a ________________ coil of wire, a solenoid, it produces a
magnetic field like the magnetic field of a bar magnet. The solenoid is known as electromagnet.
Michael Faraday
98. Faraday was an English blacksmith discovered that electricity could produce
a________________motion – the electric ________________was based on this principle.
Electromagnets
99. electromagnet – ________________ magnet made by wrapping a current-carrying wire around
an iron core
100.
the center of an electromagnet is called the ________________; it is often made of iron
101.
as long as ________________ is flowing, an electromagnet has a magnetic field
102.
when current is turned ________________, there is no longer a magnetic field
Joseph Henry’s Bigger and “Badder” Electromagnet
103.
Bagger improved the capabilities of the electromagnet by placing a ________________
rod inside the wire loops resulting in the metal being magnetized creating a magnetic field
stronger than that of wire loops around empty space.
Strength of Electromagnets
104.
there are two ways to make an electromagnet stronger
increasing the number of ________________
increasing the amount of ________________
105.
Changing the direction of an electric current causes the ________________ of an
electromagnet to reverse. This feature is important in the production of electric ________________
Electromagnets in Your World!
106.
electromagnets have many important uses
ex. ________________, telephones, ________________, electric motors
107.
Electromagnets are useful because they can be turned on and off. An electromagnet can
be used to move large quantities of metal. When the current is on the ________________ will
pick up the metal. When you want to drop it you turn off the power and the electromagnet is
________________ and the metal drops.
What do copper wire and magnets have to do with electricity?
108.
In September of 1831, Michael ________________made the discovery of
Electromagnetic Induction. Faraday attached two wires to a disc and rotated the disc between
the opposing poles of a horseshoe magnet creating an electric ________________.
Motion is essential.
109.
If you place a magnet and a conductor (copper wire), in a room together there will be
________________ electric current generated. This is because motion, from our equation for
electricity, is missing
110.
An electric current is not generated unless the magnetic field is ________________
relative to the copper wire, or the copper wire is _______________ relative to the magnetic field.
Magnetic Force on a Current
111.
A magnetic field exerts a_______________ push on an electric current with the
maximum push occurring when the current is perpendicular to the magnetic field.
112.
_______________ exert magnetic forces on each other. The forces are attractive when
parallel currents are in the same direction and are repulsive when the parallel currents are in
_______________ directions.
Electric Motors
113.
An electric motor uses the sideways push of a magnetic field to turn a current-carrying
wire_______________.
114.
Electric motors use a _______________ to change the direction of the current in the loop.
Alternating current electric motors do not use commutators.
115.
Simple Electric Generator
116. So simple electric generators found in power plants contain, magnets and copper wire that
when put into motion relative to one another create the electric _______________ that is sent
out to homes.
117. The major problem in electricity generation is where does the _______________come from
that keeps the copper wire and magnets moving relative to one another.
118.
Wind power can apply a force to the blades that turns them. The spinning blades, spin an
_______________that turns the copper wire relative to the magnetic field. As long as the blades
_______________, electricity will be generated!
Videos/Animations
119.
http://ippex.pppl.gov/interactive/electricity/static.html
120.
http://videos.howstuffworks.com/hsw/19720-electricity-and-magnetism-creatingelectricity-video.htm