what is electric flux?

how  electric field lines are associated with it?

 

The Number Of Electric Lines Of Force Passing Through The Given Surface Area Which Is Held Perpendicular To The Direction Of Electric Lines Of Force Is Called Electric Flux.

If E is Perpendicular To The Surface i. e., Parallel To The Area Vector Then θ = 0 AndΔφ = E ΔS cos0.

If θ = 180 i. e., Electric Field Vector Is In The Direction Opposite To Area Vector Then Δφ = - E ΔS

If Electric Field And Area Vector Are Perpendicular To Each Other Then θ = 90 And Δφ = 0

Thus Total Flux φ Through A Surface S Is φ ≅ ΣE.ΔS.