Question

6-With a labelled sketch, illustrate the electric field and equipotential lines about a point charge. [2 marks] (b) A dipole, as illustrated in the following figure, consists of two charges of charge magnitude, q separated by a distance, d. Point P is separated from the dipole center by a distance, r along the x-axis. For this: i) sketch and label the electric field vector contributions at P due to the two point charges and the resultant net field vector at point P. [1 marks] ii) derive a precise expression for the electric field strength at point P. [2 marks] iii) derive a simplified and approximate expression for the electric field strength at point P, using a binomial expansion and the approximation that r >> d. [2 marks] (iv) determine the magnitude of the electric field at point P where q = 3.0 x 10-6 C, d = 9.0 x 10-6 m, and r = 6.0 cm. [1 marks] (c) Describe two physical properties of water that are significantly affected by the large dipole strength of water molecules.

Answer 1