Question

Which one is the correct expression of electric flux?

(a) ∫ \(\vec{E}.d\vec{s}\)

(b) ∫ \(\vec{E^2}.d\vec{s}\)

(c) ∫ \(\vec{E}^{-1}.d\vec{s}\)

(d) ∫ \(\vec{E}.d\vec{l}\)

I had been asked this question by my college professor while I was bunking the class.

My question comes from Electric Flux topic in section Charges and Fields of Physics – Class 12

Answer 1

The correct answer is (a) ∫ \(\vec{E}.d\vec{s}\)

Explanation: Electric flux is defined as the number of field lines crossing perpendicularly through a surface area. The number of electric field lines crossing through the unit cross-section area is known as electric field intensity (E). Therefore field lines crossing through small area ds are E.ds. Taking the integral gives the flux in the entire surface.