If _s E d S=0 over a surface, then: - Vidyadip

MCQ

If $\oint_s \vec{E} \cdot \overrightarrow{d S}=0$ over a surface, then:

A
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.
C
the magnitude of electric field on the surface is constant.
D
all the charges must necessarily be inside the surface.

✓

Answer

Correct option: B.

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

b
$\phi_{\text {closed }}=0$

$\text { So } \phi_{\text {in }}=\phi_{\text {out }}$

Number of field lines entering is equal number of field lines leaving.

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