Gauss’s Law for Magnetism & Magnetic Monopoles – Rankers Physics

Bar Magnet: Practice Problem & Solution

Assertion (A): The surface integral of magnetic field over any closed surface is always zero. Reason (R): Magnetic poles are always exists in pairs.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Bar Magnet. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is Gauss's Law for Magnetism \(\oint \vec{B} \cdot d\vec{A} = 0\), which is true.

Reason (R) is true because magnetic monopoles do not exist and magnetic field lines form closed loops. (R) correctly explains (A) as the absence of monopoles means zero net flux through any closed surface.

Leave a Reply

Your email address will not be published. Required fields are marked *

Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. 20. A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from: (2018)
2. A $10\text{ eV}$ electron is circulating in a plane at right angles to a uniform field at magnetic induction $10^{-4}\text{ Wb/m}^2$ ($= 1.0\text{ gauss}$), the orbital radius of electron is (1996)
3. Assertion (A): A magnetic field can accelerate a charge particle. Reason (R): A steady current carrying wire does not generate an electric field outside it. In the light of the above statements, choose the correct answer from the options given below.
4. 22. There are four light weight rod samples A, B, C, D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted: (i) A is feebly repelled (ii) B is feebly attracted (iii) C is strongly attracted (iv) D remains unaffected Which one of the following is true? (2011 Pre)
5. 6. A 250 turn rectangular coil of length $2.1\text{ cm}$ and width $1.25\text{ cm}$ carries a current of $85\text{ }\mu\text{A}$ and subjected to a magnetic field of strength $0.85\text{ T}$. Work done for rotating the coil by $180^\circ$ against the torque is: (2017-Delhi)