Magnetism

Question 0

What type of reluctance does a temporary Magnet have

Answer 0

Low

Question 1

What type of reluctance does a permanent magnet have

Answer 1

High reluctance

Question 2

Iron content in a permanent magnet

Answer 2

Hard and high

Question 3

Iron in temporary magnet

Answer 3

Soft

Question 4

Three ways that a magnet can be demagnetized

Answer 4

AC current heat and vibration

Question 5

Three elements which are magnetic

Answer 5

Iron nickel cobalt

Question 6

State the law of magnetic repulsion/attraction

Answer 6

Opposites attract likes repel

Question 7

Five properties of magnetic flux lines

Answer 7

Always form complete loops
Represent tension along their length
Repel eachother
Don't cross
Arrange for max number of lines

Question 8

The lines of force emerge from what pole of a magnet

Answer 8

North

Question 9

Poles inside a magnet flow from

Answer 9

South to north

Question 10

What is reluctance

Answer 10

Resistance to magnetic flux

Question 11

What is permeability

Answer 11

A measure of ability to conduct flux

Question 12

What is a unit of magnetic flux

Answer 12

Weber

Question 13

High carbon steels reluctance compared to iron

Answer 13

Low

Question 14

Type of iron suitable for temporary magnets

Answer 14

Soft

Question 15

Can magnetic flux travel in a vacuum

Answer 15

Yes

Question 16

What is another name for magnetic lines of force

Answer 16

Magnetic flux

Question 17

The magnetic flux and a circuit is directly proportional to the magnetomotive force and inversely proportional to the

Answer 17

Reluctance

Question 18

The ease of which fluxes set up in the cross-section of material is called

Answer 18

Permeability

Question 19

Magnetic screens are made up of what type of reluctance

Answer 19

Low

Question 20

Why don’t magnetic lines of force collapse in the center of a magnet

Answer 20

Because they repel eachother

Question 21

Why are there no magnetic poles in the fields surrounding current caring conductor

Answer 21

No points for these lines of force diverge or converge

Question 22

Is the field around the conductor more dance or less dense closer to the conductor

Answer 22

More

Question 23

As the current in the conductor is decreased what happens to the magnetic lines of force surrounding the conductor

Answer 23

The flex lines collapse inward

Question 24

Parallel conductors caring parents in the same direction attracted to other and parallel conductors caring currents in opposite directions

Answer 24

Repel

Question 25

Using the left-hand real for coils the thumb points in the direction of

Answer 25

North pole of the coil

Question 26

List for things that affect the strength of electromagnetic coil

Answer 26

Spacing Number of turns Magnitude of current Core material type

Question 27

Materials that act in the similar way to iron are referred to as

Answer 27

Ferromagnetic

Question 28

What is the most practical way of varying the strength of an electromagnet

Answer 28

Changing the magnitude of the current through the coil

Question 29

What device connected in series with an electromagnet is normally used to change the current

Answer 29

Rheostat

Question 30

The magnetic flux in a circuit is directly proportional to the

Answer 30

Magnetomotive force

Question 31

Opposition of formation of flux lines

Answer 31

Reluctance

Question 32

The point at which all domains and magnetic materials have aligned themselves the magnetic field is referred to as

Answer 32

Theoretical saturation

Question 33

The amount of reverse magnetizing force required to remove the residual magnetism is called the

Answer 33

Coercive force

Question 34

The spreading out a flex lines in an air gap is called

Answer 34

Fringing

Question 35

Magnetic cores that are constructed of alternating layers of magnetic material are considered

Answer 35

Laminated

Question 36

As a reluctance of a magnetic circuit is increased the flux density of a circuit

Answer 36

Decreases

Question 37

The term for the leg of flux density behind magnetizing intensity is

Answer 37

Hysteresis

Question 38

Magnetic cores are usually constructed from materials

Answer 38

High permeability and low reluctance

Question 39

The amount of energy loss due to constant reversals a magnetic field an AC circuits is referred to as

Answer 39

Hysteresis loss in the form of heat

Question 40

Defined the term solenoid

Answer 40

Helically wound coil

Question 41

The core of a lifting magnet is made for material with what type of retentivity

Answer 41

Low

Question 42

Electromagnet switch

Answer 42

Relay