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JEE Main 2025 Apr 7 Shift 2, Physics Q15: Magnetic Flux

JEE Main2025Apr 7, Shift 2Physics
Q.

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

    Both (A) and (R) are correct but (R) is not the correct explanation of (A)

  2. B

    (A) is correct but (R) is not correct

  3. C

    Both (A) and (R) are correct and (R) is the correct explanation of (A)

  4. D

    (A) is not correct but (R) is correct

Solution

Gauss's law for magnetism states that the net magnetic flux through any closed surface is zero, which is exactly the mathematical statement that isolated magnetic charges (monopoles) do not exist. Consequently, magnetic field lines can never start or end at a point; they must form closed loops.

Both statements are therefore correct, and the closed-loop nature of magnetic field lines is a direct consequence of the non-existence of monopoles, so (R) properly explains (A).

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