Which is a diamagnetic material?

Options

A. Ni
B. Na
C. Au
D. Pt

Answer

To determine which of the given materials is a diamagnetic material, we can follow these steps:

### Step 1: Understand the Types of Magnetic Materials
- **Ferromagnetic Materials**: These materials are strongly magnetized in the direction of the applied magnetic field. Examples include iron, cobalt, and nickel.
- **Paramagnetic Materials**: These materials are weakly magnetized in the direction of the applied magnetic field. They have unpaired electrons that contribute to their magnetism. Examples include aluminum and sodium.
- **Diamagnetic Materials**: These materials are weakly magnetized in the opposite direction of the applied magnetic field. They do not have unpaired electrons and are repelled by magnetic fields. Examples include bismuth, copper, and gold.

### Step 2: Analyze the Given Options
The options provided are:
1. Nickel (Ni)
2. Sodium (Na)
3. Gold (Au)
4. Platinum (Pt)

### Step 3: Identify the Magnetic Properties of Each Material
- **Nickel (Ni)**: This is a ferromagnetic material.
- **Sodium (Na)**: This is a paramagnetic material.
- **Gold (Au)**: This is a diamagnetic material.
- **Platinum (Pt)**: This is a paramagnetic material.

### Step 4: Conclusion
From the analysis, the only diamagnetic material among the options is **Gold (Au)**.

### Final Answer
The diamagnetic material is **Gold (Au)**.

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