Magnetism I Pt I

If a bar magnet is taped to a piece of cork and allowed to float in a dish of water, it turns to align itself in an approximate ______-______ direction. The end of a magnet that points north is the ______ ______. The other end is the ______ ______
A magnet that is free to pivot like this is called a ______. A ______ will pivot to line up with a nearby magnet.
The end of a magnet that points north is called the _______-seeking pole or simply the ______ pole. The other end is the ______ pole. The earth itself is a large _______ _______

If the north pole of one magnet is brought near the north pole of another magnet, they _______ each other. Two south poles also _______ each other, but the north pole of one magnet exerts an ________ force on the south pole of another magnet.
Magnetism is a ______-______ force
Magnets do not need to ______ each other to exert a force on each other

Cutting a bar magnet in half produces two ______ but still ______ magnets, each with a _____ ______ and  a _____ _____.
Magnets have two types of poles, called north and south poles, and thus are ______ dipoles.
Cutting a magnet in half yields two ______  but still ______ magnets, each with a north pole and south pole
The basic unit of magnetism is thus a ______ ______

Magnets can pick up some objects, such as paper clips, but not all. If an object is attracted to one pole of a magnet, it is also attracted to the other pole. Most materials, including ______, _______, _______, and _______, experience no force from a magnet.
Only certain materials, called _______ _______, are attracted to a magnet
The most common magnetic material is ______.
Magnetic materials are attracted to both ______ of a magnet

When a magnet is brought near an electroscope, the leaves of the electroscope remain ________. If a charged rod is brought near a magnet, there is a ______ _________ force like the ones we studied in Ch 21, as there would be on any metal bar, but there is no other effect.
Magnetism is not the same as electricity. Magnetic poles and electric charges share some similar behavior, but they are not ____ ______

State 3 similarities and two differences between magnetic poles and electric charges

Every magnet sets up a _______ field in the space around it. If another magnet, such as a compass needle, is then brought into this field, the second magnet will feel the effects of the _____ of the first magnet

A magnetic field similar to a charge creates an electric field; every magnet sets up a ______ ______ in the space around it.
Electric dipole experiences a ______ when placed in an electric field, and that ______ tends to align the axis of the dipole with the ______.
The torque on the dipole is greater when the electric field is _______, hence the magnitude (or strength) of the field is _______ to the torque on the dipole
Magnetic dipole of a compass needle behaves very similarly when placed in a _______ ______. The magnetic field exerts a ______ on the compass needle, causing it to point in the ______ direction

An electric dipole rotates to line up with the _______ _______.

The compass, a magnetic dipole, rotates so that its north pole points in the direction of the _______ _______.

Because the magnetic field has both a direction and a magnitude, we represent it using a vector, .
B represents the _______ or ______ of the field
The direction of a magnetic field is the direction that the _____ pole of a compass needle points.
The strength of a magnetic field is _______ to the torque felt by a compass needle as it turns to line up with the ______ direction

The magnetic field vectors point in the direction of the ________ ________.
We represent the stronger magnetic field near the magnet by _______ vectors

1. The direction of the magnetic field at any point on the field is _______ to the field line
2. The field lines are drawn closer together where the magnitude B of the magnetic field is _______
3. Every magnetic field line leaves the magnet at its ______ pole and enters the magnet at its ______ pole

The magnetic field lines start on the ______  pole (____) and end on the ______ pole (____)
As you move away from the magnet, the field lines are ______ _____, indicating a ______ field

Iron filings can show the pattern of the magnetic field lines
Magnetic field patterns are surrounding the bar magnets, match each picture to the alignment of poles

A compass will react to the presence of a ____ _______
A compass will also ______ if you place the compass near a wire and pass a current through the wire. When the current stops, the compass goes back to its _______ orientation.
This means that an electric current produces a ______ field
The shape of the field lines depends on the ______ of the current-carrying wire

The magnetic field lines form ______ around the wire. The iron fillings are less affected by the field as the distance from the wire _______, indicating that the field is getting _______ as the distance from the wire _______.
When the current is reversed, the compass needles are ________

1. ⊗ means current goes ______ the page: point your right thumb in this direction
2. Your fingers curl _______....
3. ... so the magnetic field lines are _______ circles around the wire.
Magnetic field vectors are longer where the field is _______
Magnetic field vectors are ________ to the field lines
Field lines are closer together where the field is _______

The right-hand rule of fields helps us remember which direction compasses will point.
Explain how it works (3-story)

Represent the following Vectors and Currents that are Perpendicular to the Page
Vectors into page
Vectors out of page
Current into page
Current out of page

The magnetic field lines curve through the center of the loop, around the outside, and back through the loop's center, forming ______ ______ curves. The field lines far from the loop look like the field lines _____ from a bar magnet.

Use the _____ _____ _____ for fields to find the direction of the field lines.
Near the wire, the field lines are almost _______
The field emerges from the ______ of the loop...
... and returns around the ______ of the loop
Label the diagrams

To see what the field due to a current loop looks like, we can imagine bending a straight wire into a ______.
The field lines near the wire will remain similar to what they looked like when the wire was ______ (explain)
Farther from the wires, the field lines are no longer ______ but they still curve through the center of the ______, back around the outside and then return through the ______
If we reverse the direction of the current in the loop, all the field lines _______ direction as well

Define solenoid
The field within the solenoid is ______, mainly ______ to the axis, and reasonably _______, whereas the field outside the solenoid is very ______

The field is much ______ inside the solenoid (why?)
The field is reasonably ______ inside the solenoid

Magnetic field lines due to currents have no start or end; they form _______ ______ ______
If we consider the field lines continuing ______ a magnet, we find that these lines also form ______ _______ _______
Ordinary magnets are often called ________ _______ to distinguish their unchanging magnetism from that caused by _______ that can be switched on and off

Magnetic field strengths are measured in _____ (__).
Bonus:*State the unit equalities (4)
One tesla is quite a _____ field, so most of the field strengths you will work with are much _____ than 1T.
An electric current produces a ______ field. The geometry of the field depends on the geometry of the _______.

The field magnitude decreases as the distance from the wire ________
Suppose there's a distance r from the wire and the field has a magnitude B₀
Twice as far away the field is ______ as strong
Three times as far away, the field is _____ ______ as strong
For a long straight current wire, the magnetic field strength _______ as the distance from the wire _______ (state the formula)
Direction: Right-hand rule - wrap fingers in direction of loop, following the direction of B → thumb points toward ____  _______.