Physics, Electricity, Magnetism, Science, Math.
need to divide the surface into smaller pieces. For each smaller piece dA , we will calculate flux dφ=E*dA*cos θ. Then we have to integrate through the surface. So, the net electric flux φ will be integration of dφ through the whole surface. φ = ∮E*dA*cos θ The “∮” symbol is used for closed