Block 3: Unit 1b

What are the common magnetic materials that artificial magnets are made of?

1. ALNICO; ALuminum, NIckel and CObalt, 2. iron, 3. steel, 4. nickel, 5. cobalt.

What are three factors that effect the strength of an electromagnet?

1. How much current is flowing through the coil, 2. The number of Turns, or loops in the coil, 3. The spacing between each turn of the coil.

What are three factors that effect the strength of the magnetic field of a coil?

1. How much current is flowing through the coil, 2. The number of Turns, or loops in the coil, 3. The spacing between each turn of the coil.

What are the two most common magnetic materials used as magnets?

1. Iron, 2. Steel.

What two laws govern the effects of the magnetic poles?

1. Law of attraction, 2. Law of repulsion

What are the five basic rules for the behavior of magnetic lines?

1. Lines of magnetic force have polarity. 2. Lines of force always form complete loops. 3. Lines of force will never touch or cross one another. 4. Lines of force always form the smallest possible loops. 5. Lines of force will pass through all material.

Besides Iron and Steel, what are other magnetic materials that are used as magnets?

1. Nickel, 2. Cobalt, 3. Alnico.

What are the names of the polarities assigned to the ends of magnets?

1. North pole, 2. South pole.

What are two classifications of artificial magnets?

1. Permanent, 2. Temporary.

What are the five factors that affect artificial magnets?

1. Permeability, 2. Reluctance, 3. Retentivity, 4. Residual magnetism, 5. Effect of Heat or physical shock.

What are the only two natural magnets known of at this time?

1. The Earth, 2. Lodestone.

What are common examples of nonmagnetic substances?

1. Wood, 2. Glass, 3. Copper, 4. Lead, 5. Silver, 6. Gold.

What is a magnet?

A device or material which is the source of a magnetic field.

What magnet material is used for magnetic shielding?

A highly permeable material like iron.

What is a natural magnet?

A magnet found in nature and possesses the property of attraction.

What is a permanent artificial magnet?

A magnetized material that keeps its magnetism for a long period of time after the magnetizing force is removed.

What is a temporary artificial magnet?

A magnetized material that rapidly loses its magnetism after the magnetizing force is removed.

How are artificial magnets made?

Aligning the atoms or molecules of the material by applying a magnetic force.

What is an electromagnet?

An electrically excited magnet capable of exerting a mechanical force.

What is magnetic material?

Any substance that is capable of being magnetized or attracted by a magnet.

Do unlike poles attract or repel each other?

Attract.

How can you turn a single straight conductor into an electromagnet?

Bend the conductor into several loops creating a coil.

How do you shield a magnetic field since it will pass through all known materials?

By providing the Lines of Force a path of least reluctance diverting them away from the sensitive component.

Explain the affect of heat or physical shock on artificial magnets.

Heating or jarring a magnet can greatly weaken its magnetic force.

What magnetic material is commonly used in the core of an electromagnet and why?

Iron because it has high permeability and low reluctance.

Why would you need to shield a magnetic field?

It could interfere or disrupt sensitive electronic equipment.

How does Reluctance affect artificial magnets?

It describes how much opposition a material offers to the magnetic lines of force. It is the opposite of Permeability. Good characteristic for permanent magnets.

What factors make iron a good magnetic material to use to make a temporary magnet?

It has a high permeability and a low retentivity factors.

What factors make steel a good magnetic material to use to make a permanent magnet?

It has a high retentivity and low permeability factors.

How does Retentivity affect artificial magnets?

It is the ability to retain magnetism. Describes how difficult it is to unalign the atoms and molecules.

How does Permeability affect artificial magnets?

It is the ease with which magnetic lines of force distribute themselves through the material. good characteristic for electromagnets

What is name given to imaginary lines around a magnet that are used to represent the magnetic force of the magnetic material?

Lines of Force, also known as Flux Lines.

What is electromagnetism?

Magnetism that is induced by the electric current.

What is an artificial magnet?

Man made magnets.

Do like poles attract or repel each other?

Repel.

What are Nonmagnetic substances?

Substances that are not noticeably attracted by a magnet.

What is the name of the inside, or middle of the coil?

The Core.

Where is the North pole of an electromagnetic coil?

The North pole will be determined by the direction the coils are turned in. It can be determined using the left handed rule.

How is the strength of an electromagnet determined?

The amount of current directly corresponds with the strength of the electromagnet.

How Residual Magnetism affects artificial magnets?

The amount of magnetism left in the magnet after the magnetizing force has been removed.

What determines the direction of the magnetic field of a wire?

The direction of current.

What determines the polarity of a coil?

The direction that the coils are turned in relationship to the current flow.

Explain rule 1. Lines of magnetic force have polarity.

The lines of force always leave the North pole and enter the South pole externally.

Explain rule 3. Lines of force will never touch or cross one another.

The lines of force are polarized in the same direction. They repel each other therefore they will never cross or touch.

Explain rule 2. Lines of force always form complete loops.

The lines of force around a magnet are considered to continue through the magnet from the South pole to the North pole.

What is a magnetic field?

The lines of force or flux lines around a magnet.

Explain rule 4. Lines of force always form the smallest possible loops.

The lines of force will never touch the magnet due to electromagnetic force. However, they will take the shortest path possible to get to the South pole.

Where are most of the magnetic lines of force concentrated on a magnet?

The magnetic poles and inside the magnet.

What is an additional factor that effects an electromagnet that is in addition to those of a coil?

The material used as the core of the electromagnet.

What is Magnetism?

The property of a material that enables it to attract certain magnetic materials.

What determines the total strength of a magnetic field?

The total number of lines of force around a magnet.

What type of materials in the core will increase the strength of the electromagnet?

The use of magnetic materials.

Explain rule 5. Lines of force will pass through all material.

There is no known substance that the lines of force cannot penetrate.