Assertion (A): The earth's magnetic field is due to iron present in its core.
Reason (R ): At a high tempeature magnet losses its magnetic property or magnetism.

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.

Answer

To solve the assertion and reason question, we will analyze both the assertion (A) and the reason (R) step by step.

### Step 1: Analyze the Assertion (A)
The assertion states: "The Earth's magnetic field is due to iron present in its core."

- The Earth is composed of three main layers: the crust, mantle, and core.
- The core is primarily made of iron, but it is important to note that the iron in the core is not in a molten state; rather, it is solid.
- The Earth's core does have a high temperature, which can influence the properties of iron.
- However, the Earth's magnetic field is generated not solely due to the presence of iron, but rather due to the motion of molten iron in the outer core, which generates electric currents through the dynamo effect.

**Conclusion for Step 1:** The assertion is **false** because the Earth's magnetic field is primarily due to the movement of molten iron and not just the presence of iron in the core.

### Step 2: Analyze the Reason (R)
The reason states: "At a high temperature, a magnet loses its magnetic property or magnetism."

- It is known that materials can lose their magnetic properties when exposed to high temperatures, a phenomenon known as "thermal demagnetization."
- When the temperature exceeds a certain threshold (known as the Curie temperature), ferromagnetic materials (like iron) lose their permanent magnetism.
- This statement is true as it reflects the behavior of magnets under high-temperature conditions.

**Conclusion for Step 2:** The reason is **true** because high temperatures can indeed cause magnets to lose their magnetic properties.

### Final Conclusion
- The assertion (A) is **false**.
- The reason (R) is **true**.
- Therefore, the correct answer is that the assertion is false, but the reason is true.