6.2 Magnetic Materials

Ferromagnetic substances

• are always magnetic

• can become magnetized

• are never magnetic

• use the force

Select all that apply. These are ferromagnetic substances:

• cobalt

• iron

• nickel

• water

• rare earth metals

The atoms of ferromagnetic substances are called

• magnetic atoms

• magnetic particles

• dipoles

• north south atoms

Select all that apply to magnetic induction.

• Once a permanent magnet is brought near a ferromagnetic substance, the ferromagnetic substance becomes magnetic permanently.

• Once a permanent magnet is brought near a ferromagnetic substance, the ferromagnetic substance becomes magnetic temporarily.

• Contact between the permanent magnet and the ferromagnetic substance must be made.

• Soft and hard ferromagnetic substances describe how they feel when you touch them.

• Soft and hard ferromagnetic substances describe how long a ferromagnetic substance remains magnetic after being in close proximity to a permanent magnet.

Select all that apply to demagnetization.

• occurs when an object is dropped

• occurs when an object is heated up

• occurs when an object is wet

• substances that can be instantly demagnetized are called soft ferromagnetic materials

• substances that can be instantly demagnetized are called hard ferromagnetic materials

True or false? A magnet can change its polarity if placed in a strong enough magnetic field.

• True

• False

If a bar magnet is broken into two pieces,

• both pieces will also be magnets

• neither piece will be a magnet

• only the original north piece will be a magnet

• only the original south piece will be a magnet

Magnetic saturation occurs when

• the minimum amount of dipoles in a material are aligned in the same direction

• a material absorbs as much water as it can hold

• the maximum amount of dipoles in a material are aligned in different directions

• the maximum amount of dipoles in a material are aligned in the same direction

Which is a strategy that we can use to prevent demagnetization?

• store a ferromagnetic substance along with a bar magnet with like poles facing

• store a ferromagnetic substance along with a bar magnet with opposite poles facing

• store a ferromagnetic substance in a hot room

• pray