A: Diamagnetism is almost indipendent of temperature.
R: The induced dipole moment in a diamagnetic sample is always opposite to the magnetising field irrespective of what the internal motion of the atom is .

Options

A. If both Assertion & Reason are the true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reson is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the assertion and reason question regarding diamagnetism, we will analyze both the assertion and the reason step by step.

### Step 1: Analyze the Assertion
The assertion states: "Diamagnetism is almost independent of temperature."

- **Explanation**: Diamagnetism is a property of materials that causes them to create an induced magnetic field in opposition to an external magnetic field. This property is generally not affected by temperature changes, which means that the diamagnetic behavior remains consistent regardless of the temperature of the material.

### Step 2: Analyze the Reason
The reason states: "The induced dipole moment in a diamagnetic sample is always opposite to the magnetizing field irrespective of what the internal motion of the atom is."

- **Explanation**: In diamagnetic materials, when an external magnetic field is applied, the electrons within the atoms rearrange slightly, creating an induced dipole moment that opposes the applied magnetic field. This induced dipole moment does not depend on the internal motion of the atoms (which is influenced by temperature), meaning that even if the temperature changes and the internal motion of atoms varies, the induced dipole moment will still oppose the external magnetic field.

### Step 3: Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion. Therefore, we conclude that:

- **Assertion (A)**: True
- **Reason (R)**: True
- **Relationship**: R is a correct explanation of A.

### Final Answer
The correct answer is that both the assertion and reason are true, and the reason is a correct explanation for the assertion.

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