Answer:

1.)15 mil (.015") thick is very flexible and recommended for cost saving use for photo magnet and light weight paper objects.

2.)20 mil (.020") thick is flexible and recommended for use with paper objects.

3.)30 mil (.030") thick is less flexible and recommended for use for quality feeling save the date magnets and medium weight paper objects.

4.)60 mil (.060") thick is rigid and recommended for use only when 30 mil is not quite strong enough.

Verified answer

ANSWER

• 1. Paramagnetic materials
• The materials which are not strongly attracted to a magnet are known as paramagnetic material. For example: aluminium, tin magnesium etc. Their relative permeability is small but positive. For example: the permeability of aluminium is: 1.00000065. Such materials are magnetized only when placed on a super strong magnetic field and act in the direction of the magnetic field
• 2. Diamagnetic materials
• The materials which are repelled by a magnet such as zinc. mercury, lead, sulfur, copper, silver, bismuth, wood etc., are known as diamagnetic materials. Their permeability is slightly less than one. For example the relative permeability of bismuth is 0.00083, copper is 0.000005 and wood is 0.9999995. They are slightly magnetized when placed in a very string magnetic field and act in the direction opposite to that of applied magnetic field
• 3. Ferromagnetic materials
• The materials which are strongly attracted by a magnetic field or magnet is known as ferromagnetic material for eg: iron, steel , nickel, cobalt etc. The permeability off these materials is very very high ( ranging up to several hundred or thousand)