If a diamagnetic substance is brought near north or south pole of a bar magnet, it is

Answer

To solve the question regarding the behavior of a diamagnetic substance when brought near the poles of a bar magnet, we can follow these steps:

### Step 1: Understand Diamagnetism
Diamagnetic substances are materials that do not have any unpaired electrons and are characterized by a very weak negative susceptibility to magnetic fields. This means they are repelled by magnetic fields.

**Hint:** Recall that diamagnetic materials create an induced magnetic field in the opposite direction to an external magnetic field.

### Step 2: Analyze the Magnetic Field of the Bar Magnet
A bar magnet has a north pole (N) and a south pole (S). The magnetic field lines emerge from the north pole and enter the south pole. When a diamagnetic substance is placed in this magnetic field, it experiences the influence of this external magnetic field.

**Hint:** Visualize the magnetic field lines of the bar magnet to understand how they interact with the diamagnetic material.

### Step 3: Effect of the External Magnetic Field on the Diamagnetic Substance
When the diamagnetic substance is placed in the magnetic field, it becomes magnetized in the opposite direction to the applied magnetic field. This means that the induced magnetic field inside the diamagnetic material is directed opposite to the external magnetic field.

**Hint:** Remember that the induced magnetic field in diamagnetic materials opposes the external field due to Lenz's Law.

### Step 4: Determine the Interaction with the Bar Magnet
Since the induced magnetic field in the diamagnetic substance is opposite to the external magnetic field, the north pole of the bar magnet will repel the north pole of the induced field in the diamagnetic material, and similarly, the south pole of the bar magnet will repel the south pole of the induced field.

**Hint:** Consider the basic principle that like poles repel each other.

### Step 5: Conclusion
Based on the analysis, we conclude that a diamagnetic substance is weakly repelled by both the north and south poles of a bar magnet. Therefore, the correct answer to the question is that the diamagnetic substance is repelled by the poles.

**Final Answer:** The correct option is B: "repelled by the poles."