Question

Two metal spheres, of radii 2 cm and 1 cm with respective charge densities 5 mC/m² and -2 mC/m² , are inside a hypothetical closed surface in vacuum. What is the net electric flux through the surface ?

Answer 1

Data : σ₁ = 5 × 10^-6 C / m² ,

σ₂ = -2 × 10^-6 C/m², 

r₁ = 2 × 10^-2 m, 

r₂ = 2 × 10^-2 m

ε0 = 8.85 × 10^-12F/m

Surface charge density, σ = \(\cfrac QA\) = \(\cfrac Q{4πr^ 2}\)

∴ The charges on the metal spheres are

∴ By Gauss’s theorem, the net flux through the surface