Question

Assertion : The needle of a magnetic compass kept in strong external magnetic field, always aligns itself in north-south direction on the earth. Reason (R): Behaviour of the needle of a compass is same as that of a freely suspended bar magnet.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Compass aligns with strongest magnetic field present.

Answer 1

The Correct Option is D

To solve the given problem, we need to evaluate the truth of the assertion and the reason and the relationship between the two.

1. Understanding the Assertion: The assertion states that the needle of a magnetic compass, when placed in a strong external magnetic field, will always align itself in the north-south direction on the Earth. This is incorrect because a strong external magnetic field will overpower the Earth's magnetic field, and the compass needle will align itself with the direction of the external magnetic field, not necessarily the Earth's north-south direction.
2. Understanding the Reason: The reason states that the behavior of a compass needle is similar to that of a freely suspended bar magnet. This statement is true. A compass needle is essentially a small bar magnet that aligns itself along the magnetic field lines, just like a freely suspended bar magnet.
3. Evaluating the Statements Together: The reason correctly describes the behavior of a compass needle as being similar to a bar magnet. However, it does not provide a correct explanation for the assertion because the assertion itself is false. Instead of aligning in the Earth's north-south direction, the needle aligns with the stronger external magnetic field.
4. Conclusion: Therefore, the correct answer is: "Assertion (A) is false, but Reason (R) is true."