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Assertion: Substances which at room temp...

Assertion: Substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets.
Reason: permanent magnet can be made by placing a ferramagnetic rod in a solenoid and passing current through it.

A

If both assertion and reason are true and reason is the correct explanation of assertion.

B

If both assertion and reason are true and reason is not the correct explanation of assertion.

C

If assertion is ture but reason is false.

D

If both assertion and reason are false.

Text Solution

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The correct Answer is:
### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that substances which retain their ferromagnetic properties at room temperature for a long period of time are called permanent magnets. This is indeed true. Permanent magnets are materials that have a strong magnetic field and maintain their magnetism over time without the need for an external magnetic field. 2. **Understanding the Reason**: - The reason given is that a permanent magnet can be made by placing a ferromagnetic rod in a solenoid and passing current through it. This process is known as magnetization. When a ferromagnetic material is placed in a solenoid with an electric current, it becomes magnetized due to the magnetic field created by the solenoid. 3. **Evaluating the Truth of the Reason**: - The reason is true because the process described does indeed result in the creation of a permanent magnet. The magnetic field generated by the solenoid aligns the magnetic domains within the ferromagnetic rod, thus magnetizing it. 4. **Assessing the Relationship Between Assertion and Reason**: - While both the assertion and the reason are true, the reason does not serve as a correct explanation for the assertion. The assertion defines what a permanent magnet is, while the reason describes a method of creating a permanent magnet. Therefore, the reason does not explain why substances that retain their ferromagnetic properties are called permanent magnets. 5. **Conclusion**: - The assertion is true, and the reason is also true, but the reason is not the correct explanation of the assertion. ### Final Answer: - Assertion: True - Reason: True - Explanation: The reason does not correctly explain the assertion.
### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that substances which retain their ferromagnetic properties at room temperature for a long period of time are called permanent magnets. This is indeed true. Permanent magnets are materials that have a strong magnetic field and maintain their magnetism over time without the need for an external magnetic field. 2. **Understanding the Reason**: - The reason given is that a permanent magnet can be made by placing a ferromagnetic rod in a solenoid and passing current through it. This process is known as magnetization. When a ferromagnetic material is placed in a solenoid with an electric current, it becomes magnetized due to the magnetic field created by the solenoid. ...
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