Understanding Magnetic Materials and Repulsion

When a metal is brought near a magnet, its behavior depends on its magnetic properties. Materials can be classified into different types based on how they interact with a magnetic field. The question describes a metal that is repelled by a strong magnet. Let's look at the different categories of magnetic materials:

• Ferromagnetic Materials: These materials are strongly attracted to magnets. Examples include iron, nickel, and cobalt. They can also become permanently magnetized.
• Paramagnetic Materials: These materials are weakly attracted to magnets. Their magnetism is temporary and disappears when the magnetic field is removed. Examples include aluminum and platinum.
• Diamagnetic Materials: These materials are weakly repelled by magnets. This effect is usually very weak and often masked by other magnetic properties, but it is a fundamental property of all matter. In strong magnetic fields, the repulsion becomes noticeable. Examples include copper, gold, silver, and water.
• Non-magnetic Materials: This term is often used casually for materials that do not exhibit noticeable magnetic behavior (like strong attraction). However, strictly speaking, all materials are either diamagnetic or paramagnetic (or ferromagnetic, etc.) to some extent. Many materials considered "non-magnetic" are actually weakly diamagnetic or paramagnetic.

The question states that the metal "gets repelled" when brought near a strong magnet. Out of the common classifications, only diamagnetic materials are repelled by a magnetic field.

Therefore, a metal that is repelled by a strong magnet is a diamagnetic material. The repulsion, although weak compared to ferromagnetic attraction, is the defining characteristic described.