If _S E × dS = 0 over a surface, then: - Physics MCQ NEET 2023 2026 | ExamTest.live

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If \oint_{S} E \cdot d S = 0 over a surface, then:

A $the number of flux lines entering the surface must be equal to the number of flux lines leaving it.$
B $the magnitude of electric field on the surface is constant.$
C $all the charges must necessarily be inside the surface.$
D $the electric field inside the surface is necessarily uniform.$

Solution & Step-by-step Explanation

According to Gauss's Law, the net electric flux through a closed surface is Φ = \oint E \cdot d S = \frac{q _{e n c l ose d}}{ϵ _{0}} .If the integral is zero, the net flux is zero. This means the total number of field lines entering the volume must exactly equal the number of field lines leaving it. This happens if the net charge inside the surface is zero.

Try it yourself before checking the explanation above.

If \oint_{S} E \cdot d S = 0 over a surface, then:

the number of flux lines entering the surface must be equal to the number of flux lines leaving it.

the magnitude of electric field on the surface is constant.

all the charges must necessarily be inside the surface.

the electric field inside the surface is necessarily uniform.

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