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

Options

A. repelled by both the poles
B. repelled by the North pole and attracted by the South pole
C. attracted by the North pole and repelled by the South pole
D. attracted by both the poles

Answer

To solve the question, "If a diamagnetic substance is brought near the north or south pole of a bar magnet, it is...", we will analyze the behavior of diamagnetic substances in the presence of a magnetic field.

### Step-by-Step Solution:

1. **Understanding Diamagnetism**:
- Diamagnetic substances are materials that do not have any unpaired electrons. This means that their magnetic moments cancel each other out, resulting in a net magnetic moment of zero in the absence of an external magnetic field.

**Hint**: Recall that diamagnetic materials have paired electrons which lead to no net magnetic moment.

2. **Behavior in a Magnetic Field**:
- When a diamagnetic substance is placed in an external magnetic field (such as that produced by a bar magnet), it experiences a change in magnetic flux. According to Lenz's law, the induced magnetic moment will oppose the change in magnetic field.

**Hint**: Consider Lenz's law, which states that the induced magnetic field will always oppose the external field.

3. **Magnetization Direction**:
- Since diamagnetic materials are magnetized in a direction opposite to the applied magnetic field, they will create a magnetic moment that is directed opposite to the field of the magnet.

**Hint**: Think about how the induced magnetic moment behaves in relation to the external magnetic field.

4. **Effect Near the Magnet's Poles**:
- When brought near the north pole of a bar magnet, the magnetic field lines are directed away from the north pole. The diamagnetic substance will be magnetized in the opposite direction, leading to a repulsive force.
- Similarly, when brought near the south pole, the magnetic field lines are directed towards the south pole. Again, the diamagnetic substance will be repelled.

**Hint**: Visualize the direction of magnetic field lines and how the diamagnetic substance reacts to them.

5. **Conclusion**:
- Since the diamagnetic substance is repelled by both the north and south poles of the bar magnet, the correct answer is that it is repelled by both poles.

**Hint**: Summarize the behavior of diamagnetic substances in magnetic fields to arrive at the final answer.

### Final Answer:
The diamagnetic substance is repelled by both the north and south poles of the bar magnet.