Chapter 8/9 Electromagnetism

Question 1

What are magnetic fields used for?

Answer 1

Operate Electrical Controls
Operate Motors
Lift Equipment
Operate Transformers

Question 2

Like magnetic poles ? and unlike magnetic poles ?

Answer 2

Repel

Attract

Question 3

What is the Theory of Magnetism?

Answer 3

The ability of a material to be magnetic is because of the spin of the electrons in the material.
That each domain acts likes a small permanent magnet

Question 4

Electrons have an ? around them.

Answer 4

electrostatic field

Question 5

The lines of force from an electron’s electrostatic field travel ?

Answer 5

Towards the center of the electron

Question 6

An electron is like a small electromagnetic because,

Answer 6

The electron spins on its axis, causing its electrostatic field and magnetic fields to cross.

Question 7

Do all electrons spin in the same direction?

Answer 7

No

Question 8

Electrons that are in the same shell and spin in opposite directions cause?

Answer 8

The magnetic properties of the electrons to cancel out.

Question 9

How do some material exhibit the characteristics of a magnet?

Answer 9

Unpaired electrons are spinning in the same direction. This causes aiding magnetic fields.

Question 10

Electrons change their spin characteristics based on ?

Answer 10

Temperatures
Very High- Demagnetize
Very Cold- Prevalent

Question 11

What is Domain Theory?

Answer 11

Magnetic blocks exists in magnetic materials, when these magnetic blocks are aligned in the same direction, using magneto-motive force, the stronger the magnetic material becomes.

Question 12

What are the laws of magnetism?

Answer 12

1. Energy is required to create a magnet (magnetic field), but no energy is required to maintain a magnet (magnetic field)
2. Like Poles repel, Unlike poles attract
3. The magnetic force between two poles is directly proportional to the pole strength, and inversely proportional to the square of the distance between them.

Question 13

The effect of a magnet to be able to retain magnetism is ?

Answer 13

retentivity

Question 14

In dealing with magnetism, materials are classified into three categories, what are they?

Answer 14

Ferromagnetic, Paramagnetic, and Diamagnetic

Question 15

Ferromagnetic materials can be ? why ?

Answer 15

easily magnetized

The magnetic domains align easier

Question 16

Paramagnetic materials are

Answer 16

weakly attracted to magnets

Question 17

Diamagnetic materials ?

Answer 17

repel magnetic flux, create a very weak magnetic field in the opposite direction

Question 18

How does shielded cable work?

Answer 18

The shield is made of a Paramagnetic material and acts like a magnetic shield disrupting the flux from electromagnetic sources, that would induce a voltage into the wire.
The shield is grounded at one end of the cable to take any induced voltage and current to ground protentional.

Question 19

A magnetic field is produced when ?

Answer 19

Current flows through a conductor

Question 20

The direction in which the field encircles the conductor can be remember by using ?

Answer 20

The left hand rule for a conductor

Question 21

The magnetic field from a conductor is a ? field. Which means?

Answer 21

Concentric- originates at the center of the conductor and moves out in unbroken circles perpendiculars to electron flow.

Question 22

The size of the magnetic field is proportional to ?

Answer 22

the amount of current flow.

Question 23

Natural magnets were first known by the name ?

Answer 23

Magnetite

Question 24

A material that retains its magnetic properties is called a permanent magnet, and one that loses this characteristic easily is called a ? magnet.

Answer 24

temporary

Question 25

The cores of temporary magnets are usually made of ?

Answer 25

Iron

Question 26

Magnetic lines of force are called lines of ? .

Answer 26

Flux

Question 27

The point at which the magnetic domains of a material are all lined up is called ?

Answer 27

saturation