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प्रश्न
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.
पर्याय
a and b
b and c
c and d
a and d
उत्तर
c and d
Explanation:
We know electric flux is proportional to the number of electric field lines and the term `oint_s` E.dS represents electric flux over the closed surface.
It means `oint_s` E.dS represents the algebraic sum of the number of flux lines entering the surface and number of flux lines leaving the surface.
If `oint_s` E.dS = 0, this means the number of flux lines entering the surface must be equal to the number of flux lines leaving it.
From Gauss’ law, we know `oint_sE.dS = q/ϵ_0`, here q is the charge enclosed by , the closed surface. If `oint_sE.dS` = 0 then q = 0, i.e., net charge enclosed by the surface must be zero.
Hence all other charges must necessarily be outside the surface. This is because of the fact that charges outside the surface do not contribute to the electric flux.
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संबंधित प्रश्न
Answer the following question.
State Gauss's law for magnetism. Explain its significance.
The Gaussian surface ______.
Which of the following statements is not true about Gauss’s law?
The Electric flux through the surface
 (i) |
 (ii) |
 (iii) |
 (iv) |
Five charges q1, q2, q3, q4, and q5 are fixed at their positions as shown in figure. S is a Gaussian surface. The Gauss’s law is given by `oint_s E.ds = q/ε_0`
Which of the following statements is correct?
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- the electric field is necessarily zero.
- the electric field is due to the dipole moment of the charge distribution only.
- the dominant electric field is `∞ 1/r^3`, for large r, where r is the distance from a origin in this region.
- the work done to move a charged particle along a closed path, away from the region, will be zero.
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- field on the surface of the sphere is `(-Q)/(4 piε_0 R^2)`.
- flux through the surface of sphere due to 5Q is zero.
- field on the surface of sphere due to –2Q is same everywhere.
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- Find the critical value of y such that expansion may start.
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