NYJC_EJC Electric and Magnetic Fields Notes

9814 H3 Physics (2026) 1 ELECTRIC AND MAGNETIC FIELDS Content • Electric fields in a conductor • Gauss’s law for electric and magnetic fields • Ampère’s law for magnetic fields • Electric and magnetic dipoles Learning Outcomes Candidates should be able to: (a) show an understanding that ideal conductors form an equipotential volume and that the electric field within an ideal conductor is zero. (b) show an understanding that electric charge accumulates on the surfaces of a conductor and that the electric field at the surface of a conductor is normal to the surface. (c) recall and apply Gauss’s law for electric and magnetic fields (knowledge of the differential form of Gauss’s law is not required) and (i) solve problems involving symmetric charge distributions by relating the electric flux (in a vacuum) through a closed surface with the charge enclosed by that surface. (ii) show an understanding of the non -existence of “magnetic charge” expressed by Gauss’s law for magnetism. (d) recall and apply Ampère’s law relating the line integral of the magnetic field (in a vacuum) around a closed loop with the electric current enclosed by the loop to solve problems involving symmetric field configurations (knowledge of the differential form of Ampère’s law is not required). [Note further that candidates are not required to know Maxwell’s generalisation of Ampère’s law including the term related to the rate of change of electric flux, nor the Biot-Savart law.] (e) define the magnitude of the electric dipole moment as the product of the charge and the separation. (f) show an understanding of and use the torque on an electric dipole and the potential energy of an electric dipole to solve related problems. (g) define the magnitude of the magnetic dipole moment for a current loop as the product of the current and the area of the loop. (h) show an understanding of and use the torque on a magnetic dipole and the potential energy of a magnetic dipole to solve related problems. (i) appreciate that while electric and magnetic dipoles behave analogously, the theoretical framework at this level of study does not admit the possibility of magnetic monopoles.

9814 H3 Physics (2026) 2 show an understanding that ideal conductors form an equipotential volume and that the electric field within an ideal conductor is zero. Electric fields in a conductor When an electrical conductor is charged, all the charges (are able to move freely) will immediately move about inside the conductor due to mutual repulsion. The charges will very quickly redistribute themselve