Diamagnetic Material Identification

Magnetic materials are classified based on their behavior in an external magnetic field. The main types are diamagnetic, paramagnetic, and ferromagnetic.

• Diamagnetic materials are weakly repelled by a magnetic field. Their magnetic susceptibility is negative and small.
• Paramagnetic materials are weakly attracted to a magnetic field. Their magnetic susceptibility is positive and small.
• Ferromagnetic materials are strongly attracted to a magnetic field and can retain magnetization.

Material Properties Analysis

Let's examine the magnetic properties of the given options:

• Aluminium: Paramagnetic. It is weakly attracted by magnetic fields.
• Oxygen: Paramagnetic. Although often thought of as diamagnetic due to its molecular structure, diatomic oxygen (O₂) is paramagnetic because it has unpaired electrons.
• Lead: Diamagnetic. Lead exhibits weak repulsion when placed in a magnetic field.
• Nickel: Ferromagnetic. Nickel is strongly attracted to magnets and is commonly used in magnetic applications.

Based on these properties, Lead is the diamagnetic material among the choices.