L1 - Magnetism Quiz Flashcards
State the difference between a temporary magnet and a permanent magnet
A temporary magnet is easily magnetized, but loses its magnetism when the magnetizing force is removed.
A permanent magnet is harder to magnetize, but retains most of its magnetism when the magnetizing force is removed.
Name the material that is generally used for temporary magnets
Soft iron
Name the material that is generally used for permanent magnets
Hard steel
List three common magnetic materials
Nickel, manganese and colbalt
Generally, it is said that when all magnetic domains of a substance are aligned, its magnetic strength is at its X.
Maximum
Magnetic lines of force never X each other
Cross
Magnetic lines of force always for X or circuits.
Complete loops
Magnetic lines of force tend to be as X as X in length.
Short, possible
If a magnet has a North pole, it must have a
South pole
Magnetic lines of force tends to X each other.
Repel
Magnetic lines of force will always set up in the path of least X
Reluctance
Magnetic lines of force have a direction that indicate movement from X to X through a material such as air.
North, South
Magnetic lines of force have a direction that indicate movement from X to X through a magnet.
South, North
Magnetic lines of force tend to concentrate in a X material and spread out in a X -X material.
Ferromagnetic
Non-ferromagnetic
Magnetic materials are known as X, which means they tend to act like X.
Ferromagnetic, magnets
Magnetic fields of like polarity tend to X each others
Repel
Magnetic fields of unlike polarity tend to X each other.
Attract
Magnetic lines of force can create permanent or temporary magnets by
Induction
Magnetic lines of force are also know as magnetic X or a magnetic X.
Flux, field
Magnetic lines of force can pass through any X
Material
The North pole of the Earth is actually a magnetic X
South pole
A X is the only effective way to keep a designated area relatively free of magnetic lines of force.
Magnetic screen
State the three ways can be used to effectively demagnetize a material
AC electric current, heating to Curie Temperature, vibrating of tapping.
List three materials that are classified as ferromagnetic and explain what this term means.
Nickel, manganese, cobalt
Their magnetic domains can be easily aligned
State the name of a naturally occurring permanent magnet.
Lodestone
Which material will have more flux lines of flux when subjected to the same magnetizing force.
A - Cast iron
B- Cast steel
C - Steel Sheet
D- Copper
C - Sheet steel
Which material will have more residual magnetism after being subjected to the same magnetizing force?
A - Hard steel
B- Soft iron
C - Aluminium
D - Copper
A- Hard steel
Which material offers the least opposition (reluctance) to magnetic lines of force?
A - Cast iron
B- Cast steel
C - Sheet steel
D - Air
C - Sheet steel
Which material offers the greatest opposition ( reluctance) to magnetic lines of force?
A - Cast iron
B- Cast steel
C - Sheet steel
D- Air
D - Air
Which of the following materials is best for a magnetic screen?
A - Hard steel
B- Soft iron
C - Copper
D - Aluminium
B - Soft iron
Which of the following best describes ‘magnetic flux’?
A - A type of soldering compound
B - Two electrons spinning in opposite directions
C - Invisible lines of force
D - An attraction between Aluminium and iron
C - Invisible lines of force
What would the resistance of a material to conducting lines of flux be called?
A - Permeability
B- Retentivity
C - Residual magnetism
D - Reluctance
D - Reluctance
