Download A electric generator is a electrical machine that converts mechanical

Magnetism Notes
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____________ field lines spread out from one pole, curve around the magnet, and return to the
other pole.
o Where are magnetic field lines the strongest?
When the magnetic fields of _______ or more magnets overlap, the result is a __________ field.
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The nucleus contains ________________ and ________________. Negatively charged electrons
move randomly throughout an atom.
What happens to atoms in the magnetic domain in a magnetized material?

If you break a magnet in ½ what happens?

Earth has magnetic fields surrounding two magnetic poles. The location of Earth’s magnetic
poles __________ stay the same. __________ winds cause earth’s magnetic field to __________
out on the side of the Earth NOT facing the sun.
Electricity Notes
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Charges that are the __________ repel each other. Charges that are ____________ attract each
other.
An electric field is a region around a charged object where the object’s electric force is exerted
on other charged objects.
Transferring Charge
1. Friction:
2. Conduction:
3. Induction:
 Electric current is a _____________ flow of
electric charges through a material.
 A electric _________ is a complete path through
Which electric charges can flow.
Two different types of circuits
A:_________________________
B:__________________________

Resistance: Two factors that affect the resistance of water flowing in a pipe are ____________
and length. The diameter and length of a wire also affect resistance in a circuit.
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KNOW: AN ELECTRIC CURRENT WILL ALWAYS TRAVEL THE PATH OF LEAST RESISTANCE!!!!!!!!
Calculating Resistance:
Ohms Law : V=IR
Current
Voltage
Resistance
DEFINTION
The rate at which a
charge passes through a
given point
The difference in energy
per unit charge as a
charge moves between
two points in the path
of a current
The opposition to the
flow of electric charge.
X
1
9
2
VARIABLE
I
UNITS
Amperes (amps)
A
V
Volts
V
R
3
4
Ohms

5
6
7
8
Y
Rectangle A
V
X
1
2
3
4
5
6
7
8
Y
9
A
IR
h
A
ai
Rectangle B
h
r
ai
rdr
y
dr
1. Use Ohm’s law to calculate the voltage of a circuit with a resistance of 15.2 ohms and a
yercurrent of 0.10 amps.
h
er
as
h
2. The brake light on an automobile is connected to a 12-volt battery. If the resulting current is
a 0.40 amps, what is the resistance of the brake light?
as
ap
3. In a circuit, there is a 0.5-A current in the bulb. The voltage across the bulb is 4.0 V. What is
o the bulb’s resistance?
p
w
o
er
w
Electric Power :
The rate at which energy is transformed from one form to another is known as power. The SI unit for
power is __________.
Power= Voltage(V) X Current(A)
1. A household light bulb has about 0.5 amps of current in it. Since the standard household voltage
is 120 volts, what is the power rating for this bulb?
2. A flashlight bulb uses two 1.5-V batteries in series to create a current of 0.5 A. What is the
power rating of the bulb?
3. A hair dryer has a power rating of 1,200 W and uses a standard voltage of 120 V. What is the
current through the hair dryer?
Electrical Energy (E=Pt)
Electromagnetism Notes
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An electric current produces a magnetic field!!!!!!!!!!!!!
The magnetic field produced by a ___________ has three distinct characteristics.
o The ___________ can be turned on or off
o Its ________________ can be reversed
 Reversing the direction of the current reverses the direction of the magnetic
field!
o Its strength can be changed
 Looping the wire increases the strength of the magnetic field!
What is a solenoid?

How does a doorbell ring?

Electromagnets can be used to lift heavy objects. How does this work?

When a wire with current is placed in a magnetic field, _________________energy is
transformed into _________________ energy.
An electric current is used to turn the pointer of a galvanometer.
o A galvanometer is a device that measures small currents.
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An electric motor transforms
electrical energy into
mechanical energy.
An electric current is induced in
a conductor when the
conductor moves through a
magnetic field.
If a ____________ moves
through a coil of a wire, a
______________ is induced in
the wire.
A current can be induced two
ways
1. Move a conductor
through a magnetic
field
2. Move a magnet through
a coil of wire.
 A induced current may flow
in only ONE direction. This is called a ______________ current!
o batteries
 A induced current may reverse directions quickly over and over again. This is called a
_________________ current!
o Electric current from a generating plant transmitted at high voltages
Generators use motion in a magnetic field to produce an electric current. In most generators, a
source of __________________ energy turns huge turbines. The turbine is attached to the
armature of a generator, which produces current.
A MOTOR AND A GENERATOR ARE EXACT OPPOSITES OF ONE ANOTHER
A electric motor is an electrical machine that converts electrical energy into
mechanical energy! A electric generator is a electrical machine that converts
mechanical energy into electrical energy!

A transformer is a device that _____________ or ______________ voltage. It has two sets of coils
called primary and _____________________ coils. Voltage can be changed depending on the
number of _________ in each set of coils.
1. Step up transformer
 Increases voltage
 ________________________ coil has MORE loops than the ________________ coil
2. Step down transformer
 Decreases voltage
 ___________________ coil has MORE loops than the ____________________ coil .