Question

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 :

• A. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• B. (A) is correct but (R) is not correct
• C. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• D. (A) is not correct but (R) is correct

Hint:

Remember Gauss's law for magnetism, which states that the net magnetic flux through any closed surface is zero. This law is a mathematical formulation of the non-existence of magnetic monopoles and directly leads to the property that magnetic field lines are continuous and form closed loops.

Answer 1

The Correct Option is C

To analyze the given statements, let's examine the assertion and the reason:

• Assertion (A): Magnetic monopoles do not exist.
• Reason (R): Magnetic field lines are continuous and form closed loops.

Explanation:

1. Magnetic monopoles refer to hypothetical particles that have only a single magnetic pole (either a north pole without a south pole, or vice versa). In contrast, all known magnets have both a north and a south pole. As of modern physics, magnetic monopoles have not been observed in nature.
2. Magnetic field lines provide a visual representation of a magnetic field. These lines illustrate the direction and strength of the magnetic field at various points in space. Importantly, magnetic field lines always form closed loops. This means that the field line starting from the north pole of a magnet returns back to the south pole, reinforcing the non-existence of isolated magnetic poles (monopoles).

Since magnetic field lines do indeed form closed loops, they corroborate the statement that isolated monopoles do not exist. The non-existence of magnetic monopoles is therefore a direct consequence of the nature of magnetic field lines, which are continuous and do not terminate on a monopole.

Conclusion: The assertion that magnetic monopoles do not exist is correct, and the reason that magnetic field lines form closed loops supports this assertion. Thus, both statements are correct, and the reason given is indeed the correct explanation of the assertion.

Therefore, the correct option is: Both (A) and (R) are correct and (R) is the correct explanation of (A).

Answer 2

Step 1: Analyze Assertion (A).
Assertion (A) states that magnetic monopoles do not exist. This is a fundamental principle in magnetism, supported by all experimental evidence so far. While theoretical frameworks like Dirac's theory suggest the possibility of magnetic monopoles, they have not been observed.
Therefore, Assertion (A) is considered correct within the current understanding of physics.
Step 2: Analyze Reason (R).
Reason (R) states that magnetic field lines are continuous and form closed loops. This is a direct consequence of Gauss's law for magnetism (\( \oint \vec{B} \cdot d\vec{A} = 0 \)), which implies that there are no isolated magnetic poles (sources or sinks of magnetic field). The magnetic field lines originate from the north pole of a magnetic material and terminate at the south pole, but they continue inside the material, forming closed loops.
Therefore, Reason (R) is also correct.
Step 3: Determine if Reason (R) is the correct explanation of Assertion (A).
The fact that magnetic field lines form closed loops is a direct consequence of the non-existence of isolated magnetic poles (monopoles). If magnetic monopoles existed, the magnetic field lines would originate from a north monopole and terminate at a south monopole, and they would not necessarily form closed loops. The continuity and closed-loop nature of magnetic field lines are a manifestation of the fundamental absence of magnetic monopoles.
Therefore, Reason (R) is the correct explanation of Assertion (A).