The symbol of electric flux is represented by two Greek letters, Phi (Φ) and Psi (Ψ). Phi (Φ) is used to represent the electric flux density, which is the amount of electric flux per unit area. Psi (Ψ) is used to represent the electric flux, which is the total amount of electric flux passing through a given area. Both symbols are commonly used in physics and engineering to represent electric flux.