According to gauss theorem, the electric flux on a closed surface depends on?

  1. The area of open surface
  2. Charge enclosed
  3. Magnetic field of charge
  4. Charge outside the sphere

Answer (Detailed Solution Below)

Option 2 : Charge enclosed
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Detailed Solution

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CONCEPT

  • Electric Flux: It is defined as the number of electric field lines passing through the perpendicular unit area.
F1 J.K 13.6.20 Pallavi D9
  • Electric Flux = (Φ) = EA [E = electric field, A = perpendicular area]
  • Electric flux (Φ) = EA cos θ [where θ is the angle between area plane and electric field]

F1 J.K 13.6.20 Pallavi D10

F1 J.K 13.6.20 Pallavi D11

F1 J.K 13.6.20 Pallavi D12

  • The flux is maximum when the angle is 0°
  • Gauss Law: According to gauss’s law, total electric flux through a closed surface enclosing a charge is 1/ϵ0 times the magnitude of charge enclosed.

\(i.e.~{{\mathbf{\Phi }}_{net}}=\frac{\left( {{Q}_{in}} \right)}{{{\epsilon }_{0}}}\)

\(i.e.~\oint \vec{E}\cdot d\vec{S}=\frac{{{Q}_{in}}}{{{\epsilon }_{0}}}\)

Where, Φ = electric flux, Qin = charge enclosed the sphere, ϵ0 = permittivity of space (8.85 × 10-12 C2/Nm2), dS = surface area

EXPLANATION

According to gauss’s law,

The flux of the net electric field through a closed surface equals the net charge enclosed by the surface divided by ϵ0.

\(\oint \vec{E}\cdot d\vec{S}=\frac{{{Q}_{in}}}{{{\epsilon }_{0}}}\)

Electric flux on a closed surface only depends on the enclosed charge.

∴ Option 2 is correct
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