Electromagnetism - LECTURE 01 Part 02/04 - by Prof Robert de Mello Koch

This video forms part of a course on Electromagnetism by Prof Robert de Mello Koch held at AIMS South Africa in 2013.

Please visit https://sites.google.com/a/aims.ac.za... to download the supporting course notes.

The concept of a field is introduced and the necessity of a description in terms of fields is explained.
The interaction between static charges, using the superposition principle, is developed. The interaction of a neutral atom with a point charge is used to motivate the idea of polarization. Concepts developed up to this point are used to study the interaction of charged sticky tape. In particular, the charge lost by a piece of tape when it is ripped from a table top, is computed. A simple electroscope is built from polystyrene cups and empty soft drink cans. The electroscope is studied using the theory already developed with an emphasis on the ideas used in arriving at a suitable model. The Gauss Law is
developed and used to compute the field from an infinite uniformly charged sheet. Electrical potential energy and the electric potential are introduced. Simple electric circuits are considered. The Joule heating law is derived.

The Biot-Savart and then the Lorentz law are introduced. The theory developed is used to estimate the magnetic field from a fridge magnet using a simple model in which each atom contributes a dipole moment. Theory and experiment are compared.

Vector calculus and Maxwells equations are developed next. Particular care is used to motivate the correction to Amperes Law. Light is described as a solution to Maxwell's equations. The energy carried by light is computed. The amount of energy radiated by an accelerated charge is computed. The Lorentz transformations are derived as the set of symmetries leaving Maxwell's equations invariant. Some simple consequences of Special Relativity are described.