Define electric dipole moment. Is it a scalar or a vector?

(a) Electric dipole moment- The strength of the electric dipole is measured by the quantity of electric dipole moment. Its magnitude equals the product of the magnitude of their charge and the distance between the two charges. Electric dipole moment. p=q×d It is a vector quantity. In vector form it is written as →p=q×→d, where the direction of →d is from negative charge to positive charge. Electric Field of dipole at points on the equatorial plane The magnitude of the electric field due to the two charges +q and -q are given by E+q=q4πϵ01r2+a2. (i) E−q=q4πϵ01r2+a2. (i) ∴E+q=E−q The direction of E+q and E−q are shown in figure: The components normal to the dipole axis cancel away. The components along the dipole axis add up. ∴Total electric field E=−(E+q+E−q)cosθ^pE=2qa4πϵ0(r2+a2)3/2^p. (iii) At large distance (r>>a) this reduces to E= pqa4πϵ0r3^p. (iv) →p=q×2a^pE=−→p4πϵ0r3(r>>a)(b) Equipotential surface due to electric dipole- The potential due to the dipole is zero at the line bisecting the dipole length.