Easy MCQ +4 / -1 PYQ · JEE Mains 2025

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): Magnetic monopoles do not exist.

Reason (R): Magnetic field lines are continuous and form closed loops.

In the light of the above statements, choose the most appropriate answer from the options given below:

  1. A <p>Both (A) and (R) are correct and (R) is the correct explanation of (A)</p> Correct answer
  2. B <p>(A) is not correct but (R) is correct</p>
  3. C <p>(A) is correct but (R) is not correct</p>
  4. D <p>Both (A) and (R) are correct but (R) is <b>not</b> the correct explanation of (A)</p>

Solution

<p><p>The assertion states that magnetic monopoles do not exist. This is consistent with current experimental findings and the standard formulation of Maxwell's equations.</p></p> <p><p>The reason provided is that magnetic field lines are continuous and form closed loops. This is mathematically expressed by the Maxwell equation:</p> <p>$\nabla \cdot B = 0$</p> <p>This equation tells us that there are no "sources" or "sinks" of magnetic fields (unlike electric fields, which can originate or terminate at charges). In other words, magnetic field lines neither begin nor end; they loop continuously.</p></p> <p><p>Since the fact that the magnetic field lines form closed loops is a direct consequence of the absence of isolated magnetic charges (monopoles), the reason correctly explains the assertion.</p></p> <p>Thus, both (A) and (R) are correct, and (R) is the correct explanation of (A).</p> <p>The most appropriate answer is Option A.</p>

About this question

Subject: Physics · Chapter: Magnetism · Topic: Bar Magnet and Magnetic Field

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