Assertion : The properties of paramagnetic and ferromagnetic substance are not effected by heating.
Reason : As temperature rises, the alignment of molecular magnets gradually decreases.

Options

A. If both Assertain and Reason are true and Reason is the correct explanation of Assertain
B. If both Assertain and Reason are true but Reason is not correct explantion of Assertain
C. If Assertion is true but Reason is false
D. If Assertion is false but Reason in true.

Explanation

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

### Step 1: Analyze the Assertion
The assertion states: "The properties of paramagnetic and ferromagnetic substances are not affected by heating."

- **Understanding Paramagnetism and Ferromagnetism**:
- Paramagnetic substances have unpaired electrons that align with an external magnetic field, but this alignment is weak and temporary.
- Ferromagnetic substances have a strong and permanent alignment of magnetic moments even in the absence of an external field.

- **Effect of Heating**:
- When the temperature of a paramagnetic or ferromagnetic substance increases, thermal agitation increases, which disrupts the alignment of magnetic moments.
- For paramagnetic materials, the susceptibility (a measure of how much a material will become magnetized in an external magnetic field) is inversely proportional to temperature. As temperature increases, susceptibility decreases, meaning the magnetic properties are affected.

**Conclusion for Assertion**: The assertion is **false** because heating does affect the properties of both paramagnetic and ferromagnetic substances.

### Step 2: Analyze the Reason
The reason states: "As temperature rises, the alignment of molecular magnets gradually decreases."

- **Understanding the Reason**:
- As temperature rises, the thermal energy causes increased motion of the molecules, which disrupts the alignment of the magnetic moments.
- This is consistent with the behavior of both paramagnetic and ferromagnetic materials, where increased temperature leads to decreased alignment and thus decreased magnetic susceptibility.

**Conclusion for Reason**: The reason is **true** because it accurately describes the effect of temperature on the alignment of molecular magnets.

### Final Conclusion
- The assertion is false, and the reason is true. Therefore, the correct answer is that the assertion is false, but the reason is true.

### Summary
- **Assertion**: False
- **Reason**: True