A permanent magnet (in contrast to an electromagnet).
Ferromagnetic
permanent magnets.
Permanent
up to six hours.
Pairs - although monopoles have long been speculated about!
A magnetic read write-head moves a cross a spinning disk changing the polarity of tiny magnetic particles in the disk(s). This can then be read at a later date.
An instrument that makes small, distant objects visible is a telescope. Binoculars and scopes are also used for seeing long distance.
No, a galss cup does not keep any drink warm long.
Permanent magnets
magnetic
Permanent magnets.
Permanent magnets.
Austenite is not magnetic. It's an allotrope of iron, and has some alloying agents, but it only exists at high temperatures that are well above the Curie point of whatever iron alloy is heated. We know that metals that are magnetic will lose their magnetic properties above a certain temperature (called the Curie point), which varies for different metals and alloys. It is not possible for iron alloys (or any steels) to make the transition to austenite until well past the Curie point of the metal. Any magnetic properties the metal had will have long ago disappeared.
Basically, no. But avoid sharp objects (including long fingernails) and keep things clean.
Iron (Fe) Cobalt (Co) and Nickel (Ni) iron, steel, nickel, and cobalt all have magnetic properties. Lodestone is also magnetic and was used to make early compasses a long time ago because it has magnetic metal elements in it.
Sadly, no matter how long or how intently I keep my gaze fixed above, I seem to be unable to make out either the objects or the forces acting on them.
Temporary magnet: good example is an electromagnet. It maintains magnetic attraction only so long as an electric current surrounds it. Permanent magnet: most common. Example: bar magnet. Will maintain magnetic properties for quite a while, although they can be eventually demagnetized.
Ancient earth reveal magnetic field as it was from long ago. :) :) :)
Magnetic epochs last a long period of time, geologically. It is when the earth's magnetic field is the same polarity.
If one continously heats a particular magnet to high temperatures or long time or both, it loses it magnetism because the particles get excited and start forming no-magnetic arrangements.