Magnets And Magnetism Quiz

"Magnetically soft" materials are substances that can easily lose their magnetism. These materials have low coercivity, meaning they require less external magnetic field to demagnetize. They are often used in applications where magnetism needs to be easily controlled or switched on and off, such as in transformers or electric motors. Iron oxide materials, on the other hand, are not specifically known for losing magnetism quickly, and expensive materials do not necessarily have any correlation with their magnetic properties.

The statement is false because the horseshoe magnet is actually stronger than the bar magnet. The horseshoe magnet has a U-shape, which allows for a stronger magnetic field to be concentrated at the ends of the U. This design makes the horseshoe magnet more efficient and stronger compared to the bar magnet, which has a weaker magnetic field that is spread out along its length. Therefore, the horseshoe magnet is considered to be stronger than the bar magnet.

When two magnets have one force field, it means that their magnetic fields are aligned in the same direction. This alignment causes the magnets to attract each other. The opposite poles of the magnets (north and south) attract each other, while the like poles (north and north, or south and south) repel each other. Therefore, when the magnets have the same force field, they attract each other.

Temporary magnets become magnetized for a short period of time through induction. Induction occurs when a magnetic field is created in a material, such as a metal, by bringing it close to a permanent magnet. This causes the alignment of magnetic domains within the material, resulting in temporary magnetization. Once the magnet is removed, the material loses its magnetism. Magnetite is a naturally occurring magnetic mineral, but it is not directly related to the process of induction in temporary magnets.

A polar magnet has a north and a south pole. Unlike a plastic magnet or an electronic magnet, which do not have distinct poles, a polar magnet has a clear magnetic field with opposite poles. Therefore, it is the only option among the given choices that fits the description of having both a north and a south pole.

A bar of iron placed across the ends of a horseshoe magnet is called a "keeper". This is because it helps preserve the magnetism of the horseshoe magnet by creating a closed magnetic circuit. The keeper acts as a magnetic pathway, preventing the magnetic field from leaking out and keeping the magnetism strong. Without a keeper, the horseshoe magnet could gradually lose its magnetism over time.

The first compass was invented in A.D. 1087.