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Question
Answer the following question.
State Gauss's law for magnetism. Explain its significance.
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Solution
The net magnetic flux (ΦB) through any closed surface is always zero.
This law suggests that the number of magnetic field lines leaving any closed surface is always equal to the number of magnetic field lines entering it.
Suppose a closed surface S is held in a uniform magnetic field `vecB`.
Consider a small vector area element Δ`vec"S"` of this surface.
Magnetic flux through this area element is defined as ΔΦB = `vec"B".Δvec"S" `
Considering all small area elements of the surface, we obtain net magnetic flux through the surface as:
ØB = `sum_"All" ΔØ_"B" = sum_"All" vec"B". Δvec"S" = 0`
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RELATED QUESTIONS
State and explain Gauss’s law.
A charge ‘q’ is placed at the centre of a cube of side l. What is the electric flux passing through each face of the cube?
The Gaussian surface ______.
Which of the following statements is not true about Gauss’s law?
Gauss' law helps in ______
The Electric flux through the surface
 (i) |
 (ii) |
 (iii) |
 (iv) |
If `oint_s` E.dS = 0 over a surface, then ______.
- the electric field inside the surface and on it is zero.
- the electric field inside the surface is necessarily uniform.
- the number of flux lines entering the surface must be equal to the number of flux lines leaving it.
- all charges must necessarily be outside the surface.
If the total charge enclosed by a surface is zero, does it imply that the elecric field everywhere on the surface is zero? Conversely, if the electric field everywhere on a surface is zero, does it imply that net charge inside is zero.
In the diagram, the total electric flux through the closed surface ‘S’ is:
[Given q = charge ε0 = permittivity of free space]
