Transcript Green-blue brushed metal and curves design template

An object that attracts iron containing objects
Has two poles
North and south
Law of polesLike poles repel while opposite attract
A bar magnet is divided into two pieces. Which
of the following statements is true?
A) the bar magnet is demagnetized
B) the magnetic field of each separated piece
becomes stronger
C)the magnetic poles are separated
D) two new bar magnets are created
A region in which the magnetic force can be
detected
The magnetic fields go from the north pole to
the south pole
Magnetic Field Diagram # 3
Also called flux lines
Never cross each other
The closer they are the stronger the field
???
The north pole is actually the south pole of
Earth’s magnet!
The magnetic south pole is near the geographic
North pole and vice versa.
This is why compasses point to the south pole
of a magnet in a magnetic field but we say that
compasses point north
Which of the following statements is most correct?
A. The north pole of a freely rotating magnet points north
because the magnetic pole near the geographic North Pole is
like the north pole of a magnet.
B. The north pole of a freely rotating magnet points north
because the magnetic pole near the geographic North Pole is
like the south pole of a magnet.
C. The north pole of a freely rotating magnet points south
because the magnetic pole near the geographic South Pole is
like the north pole of a magnet.
D. The north pole of a freely rotating magnet points south
because the magnetic pole near the geographic South Pole is
like the south pole of a magnet.
Caused by moving
charges
Any time a charge moves
(current) a magnetic field
is created
So….electric current can
create magnetic fields
Magnetic force is created
by two magnetic fields
occupying the same
space
Electrons have a spin, so
there are moving charges
in atoms
Most atoms’ electrons are
paired up though and
spinning in opposite
directions, so the fields
that are generated are
cancelled
When the electrons are
not paired up then the
fields are not cancelled
These materials can be
Electric Fields
Caused from a positive or
negative charges
Charges can be moving or
stationary
Fields move from positive
to negative
Can be caused by a single
charge
Magnetic Fields
Caused from moving
charges
Field lines move from
north to south pole
Always caused from two
poles
When there is an electric
current a magnetic field
(B-field) is created around
it
Use the right hand rule
Thumb will point in the
direction of the current
Fingers will curl in the
direction of the B field
An electric current flows into the page. What is
the direction of the magnetic field?
A) to the bottom of the page
B)to the top of the page
C)Clockwise
D)counter-clockwise
E) to the right
A current is flowing to the right, in what
direction will the magnetic field be?
A)Into the page
B)out of the page
C)clockwise
D)counter-clockwise
E)to the left
Solenoid is a long helically wound coil of wire
Solenoids produce a strong magnetic field by
combining several loops
More loops= stronger magnetic field
A charge moving through a magnetic field
experiences a magnetic force
The force is proportional to the
Charge
Velocity
Magnetic field
Alternative Right Hand
Rule
Direction of your
palm=magnetic force
Fingers= magnetic field
lines
Thumb=velocity of
particle
When drawing
An X= into the page
A = out of the page
A positive charge enters a uniform magnetic
field as shown. What is the direction of the
magnetic force? Velocity is pointed up and fields
pointed into page.
A) out of the page
B) into the page
C) downwards
D) to the right
E) to the left
A positive charge enters a uniform magnetic
field. What is the direction of the magnetic
force? The velocity is to the right and the
magnetic field is into the page.
A) out of the page
B) into the page
C) Downwards
D) upwards
E) to the left
If two wires were parallel
to each other and the
current was in the same
direction, they would
attract
If the current is in the
opposite direction they
would repel
Changing magnetic fields
creates a potential
difference (or EMF) in a
conductor
So.. Magnetic fields can
create currents
This allows physical work
to create electrical energy
Power that is generated for transmission (for
homes and buildings) is ramped up (about
100000 V) when it arrives at your home you
need it at a lower level (120V)
To convert voltage to a higher or lower value we
use a transformer
Consists of a primary coil and a secondary coil
The current flows through the primary
magnetic field
Magnetic field current in secondary coil
We use alternating current for this
When a transformer increases voltage it is
called a step up (more secondary coils)
When a transformer decrease voltage it is called
a step down (more primary coils)