Unit 5 Magnetism

A magnet is an object that:

Attracts or repels another object

Magnets are usually ______ solids

Metal

A magnet has:

Two poles

The two poles of a magnet are called:

Dipoles

The two poles of a magnet are called:

North and South pole

A dynamo is a type of:

Generate

A dynamo produces a:

Direct current

What is each fragment called?

Domain

What are domains?

Pockets of dipoles

Draw the domains of a non-magnetic object

A transformer is a:

Device

A transformer is used to:

Change the size of an alternating voltage or current

Ways to cause a metal to become a magnet:

Through electricity and stroking it

Diagram of using current to turn a metal into a magnet:

What happens to the dipoles of a metal when it becomes a magnet?

Aligned in one direction

Materials whose dipoles can be rearranged to align in the same direction are callled:

Ferromagnetic materials

Example of ferromagnetic material:

Iron

Types of magnets:

Permanent and temporary

Example of permanent magnet:

Steel

Example of temporary magnet:

Iron

Draw magnetic field lines around the magnets

Draw magnetic field lines around the magnets

Draw magnetic field lines around the magnets

Draw magnetic field lines around the magnets

Draw the domains of a magnetic object

Draw magnetic field lines around the magnets

Draw diagram of strong and weak magnetic field

What is the point labelled P called?

Neutral point

A neutral point has a ______ magnetic force

Zero

Unit for magnetic field strength:

Tesla

Symbol for Tesla:

T

Like poles ______

Repel

Unlike poles ______

Attract

What is this called?

U-shaped magnet

Draw electric field lines around a U-shaped magnet

Cutting a magnet in half will not:

Isolate a single north / south pole

When a magnet is cut in half, it becomes:

Two magnets

We can use the term magnetic dipole moment to describe the:

Internal direction of a magnet

We use the term ______ to describe the internal direction of a magnet

Magnetic dipole moment

The magnetic dipole moment is also called:

Magnetic moment or magnetic dipole

The magnetic dipole moment can be represented by an:

Arrow that connects magnetic field lines

An arrow that represents the magnetic dipole moment enters the:

South end

An arrow that represents the magnetic dipole moment leaves the:

North end

Draw the magnetic dipole moment

A current-carrying wire produces a:

Magnetic field

If current goes up, does magnetic field go clockwise or counterclockwise?

Counterclockwise

If current goes down, does magnetic field go clockwise or counterclockwise?

Clockwise

THe shape of the magnetic field lines depends on the:

Shape of the wire

More coils of a wire lead to a ______ magnetic field

Stronger

This symbol denotes the:

Movement of charges or vector force into page

This symbol denotes the:

Movement of charges or vector force out of page

Diagram that shows why dot represents vector out of page and x represents vector into page:

What does this diagram represent?

Vectors into page

What does this diagram represent?

Vectors out of page

A solenoid is a:

Coil of current carrying wire

The more loops a wire has, the ______ the magnetic field

Stronger

Magnetic fields exert forces on ______

Moving charges

When a charged particle is moving through a magnetic field, a ______ acts on it

Magnetic field

Diagram of a solenoid:

The magnetic force acting on a charged particle moving through a magnetic field has a ______ when the charge moves perpendicularly to magnetic field lines

Maximum value

The magnetic force acting on a charged particle moving through a magnetic field has a ______ when the charge moves along the magnetic field lines

Zero value

In the right hand rule, what does the thumb represent?

Current

In the right hand rule, what do the fingers represent?

Magnetic field

In the right hand rule, what does the palm represent?

Force

The right hand palm rule is only true for:

Positive charges

If the charge is negative and we use the right hand palm rule, we have to:

Change direction of force

Equation for calculating magnetic force in terms of charge:

F = qBvsin(theta), where q = charge in C, B = magnetic field strength in T, v = velocity in m/s, and theta is the angle between velocity of the charge and the direction of the field

Diagram representing theta in F = qBvsin(theta) is theta is a slanted angle:

Equation for calculating magnetic force in terms of current:

F = ILBsin(theta)

How to derive this equation: F = ILBsin(theta)?

F = qBvsin(theta), and v=L/t so F = qB(L/t)sin(theta) and q/t = I so F = ILBsin(theta)

What must we know to use right hand grip rule?

Direction of current / charge and direction of magnetic field

What do fingers represent for straight conductor?

Direction of magnetic field

What does thumb represent for straight conductor?

Direction of current / charge

What do fingers represent for coil / solenoid?

Direction of current / charge

What does thumb represent for coil / solenoid?

North pole

Which side is the north pole?

Right

What do you have to know to use right hand rule?

Direction of current / charge, direction of magnetic field, force

What does palm represent?

Force

Right hand rule only applies to what?

Positive charges

What must you do when using right hand rule for negative charge?

Flip direction of force

If the angle is slanted, does the direction of force change? (F=qBvsin(theta))

No

If the angle is slanted, what changes? (F=qBvsin(theta))

Magnitude of force

What is the direction of force?

No force

Why is there no force?

Because velocity of charge is anti-parallel to field

Why is there no force when velocity of charge is parallel or anti-parallel to field?

Because F=Bqvsin(theta) and sin(0) and sin(180) are both equal to 0, causing F = 0

What is the direction of force?

No force

Why is there no force?

Because no velocity of charge

Why is there no force when charge is not moving? (explaining mathematically)

F=Bqvsin(theta) so when v = 0, F = 0

What field does unmoving charged particle have?

Electric field

Why is there no force when charge is not moving? (explaining in words)

An unmoving charged particle does not have a created magnetic field, so it doesn’t interact with another magnetic field to create force

What field does an unmoving charged particle lack?

Magnetic field

If a charged particle moves right to go into a magnetic field pointing into the page, how does it move afterwards?

In circular motion

Why does a charged particle move in circular motion after moving right to go into a magnetic field pointing into the page?

Because force is up, then left, then down, then right, and so on

How must charge go into a field to move in circular motion once enters field?

Perpendicular to field direction

What happens to a charged particle after entering magnetic field perpendicularly?

Leaves it while in circular motion

What angle is made between force and direction of path of circular motion of charge?

90 degrees

Draw diagram of circular motion of charged particle in magnetic field:

Does kinetic energy of charge in circular motion change?

No

Why does kinetic energy of charge in circular motion not change?

Because speed remains constant

Why does speed of charge in circular motion remain constant over time?

Magnetic force is not doing work on it