Diamagnetic materials are feebly repelled by a magnet. Diamagnetism is a property exhibited by certain materials that causes them to create a weak magnetic field in opposition to an externally applied magnetic field. This effect is very weak and is easily overcome by stronger magnetic fields.

Diamagnetic materials have all of their electrons paired up in their atomic or molecular orbitals, resulting in a net magnetic moment of zero. When a diamagnetic material is exposed to a magnetic field, the electrons in the material slightly rearrange themselves to create a magnetic field in the opposite direction. This opposing magnetic field causes the material to be repelled by the magnet.

Some examples of diamagnetic materials include bismuth, copper, gold, and water. These materials have a weak response to a magnetic field and are often referred to as non-magnetic materials.

Diamagnetism is a fundamental property of matter and is present in all materials to some degree. However, its effects are typically very weak and only become noticeable in the presence of strong magnetic fields. In comparison to paramagnetic, ferromagnetic, and ferrimagnetic materials, diamagnetic materials exhibit the weakest response to magnetic fields.

In summary, diamagnetic materials are feebly repelled by a magnet due to their ability to create a weak magnetic field in opposition to an externally applied magnetic field. This diamagnetic response is a result of the arrangement of electrons in these materials and is much weaker than the responses exhibited by paramagnetic, ferromagnetic, and ferrimagnetic materials.