Gauss's Law For Magnetism

Question

The net magnetic flux through any arbitrary closed surface is always exactly zero; this fundamental result is a direct consequence of the fact that

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NCERT Class 12, Chapter 5 (Magnetism and Matter) states Gauss's law for magnetism: the net magnetic flux through any closed surface is zero, written $\oint \vec{B}\cdot d\vec{A} = 0$. Physically this means magnetic field lines always form closed loops, with no starting or ending points, because there are no isolated magnetic charges (monopoles). Every field line that enters a closed surface must also leave it, so the inward and outward contributions cancel exactly. The option 'field lines can begin on charges' describes electric fields and Gauss's law for electricity, not magnetism. The option 'the field is always non-uniform' is unrelated to flux and is untrue in general. The option 'magnetic forces do no work' is a true but separate fact about the Lorentz force, not the cause of zero flux. Plausibility check: for electric fields the flux equals enclosed charge over $\varepsilon_0$; the magnetic analogue is zero precisely because the magnetic 'charge' (monopole) has never been observed, confirming the first option.

Gauss's Law For Magnetism

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Gauss's Law For Magnetism

Select the correct option:

🔒 Solution Hidden from View

More magnetic effects of current and magnetism Practice Questions

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A galvanometer of resistance 50 Ω shows full-scale deflection at 2 mA; what shunt resistan...

In a moving coil galvanometer the deflection produced is directly proportional to the current becaus...

A rectangular coil of 50 turns and area 2×10−2 m2 carries a current of 1.5 A whil...

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About This Question

Solution

The magnetic susceptibility of a paramagnetic sample is measured as $0.006$ at a temperature of $300...

In a region with a uniform electric field of $3 \times 1 0^{4}$ V/m perpendicular to a magnetic field...

A circular loop of radius $R$ carries current $I$ ; the magnetic field at an axial point located a di...

A galvanometer of resistance $50 Ω$ shows full-scale deflection at $2$ mA; what shunt resistan...

A rectangular coil of $50$ turns and area $2 \times 1 0^{- 2}$ m $^{2}$ carries a current of $1.5$ A whil...

To convert a galvanometer of resistance $60 Ω$ and full-scale current $5$ mA into a voltmeter ...

A bar magnet of magnetic moment $0.8$ A·m $^{2}$ is held at $3 0^{\circ}$ to a uniform magnetic field of...