Department of Physics, Unit Catalogue 2008/09 |
PH20014 Electromagnetism 1 |
| Credits: 6 |
| Level: Intermediate |
| Semester: 2 |
| Assessment: EX 100% |
| Requisites: |
| Before taking this unit you must (take PH10005 or take PH10053) and (take PH10006 or take PH10051) and take PH20019 |
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Aims: The aims of this unit are to develop a vectorial description of electric, magnetic and electromagnetic fields in infinite materials and at boundaries between materials, to derive some individual solutions and to make use of them in a few important applications. A further aim is to provide an introduction to the operation of lasers.
Learning Outcomes: After taking this unit the student should be able to: * derive and interpret Maxwell's equations and their solution in vacuum; * list the distinguishing features of electromagnetic plane waves and write down a mathematical expression for a linearly or circularly polarised light wave; * analyse in detail the propogation of vectorial plane waves in vacuum and in various materials; * describe the origins of polarisation and magnetisation in materials; * match electric and magnetic fields at boundaries between materials and explain the origins of Brewster's angle and total internal reflection; * describe how lasting action is obtained and maintained and outline the main properties of laser light. Skills: Numeracy T/F A, Problem Solving T/F A. Content: Introduction to Maxwell's equations (7 hours): Derivation of integral and differential forms of Maxwell's equations and continuity equation. The wave equation in source-free vacuum. Plane wave solutions. Electromagnetic plane waves (3 hours): 3D plane waves, vector nature of electromagnetic wavesl relationships between E, B and k. Impedance. Electromagnetic energy and the Poynting vector. Radiation pressure. Polarisation; Law of Malus, circular and elliptical polarisation. Birefringence, wave plates. Maxwell's equations in infinite materials (6 hours): Concepts of linearity, isotropy and homogeneity. Characterisation of materials in terms of macroscopic parameters. Dipoles, susceptibility and polarisation / magnetisation. The modified wave equation; solution in conductors, dielectrics, lossy media and plasmas. Boundaries between media (4 hours): The general electromagnetic boundary conditions. Plane waves at a planar boudary, general angle of incidence (Fresnel equations). Total internal reflection and evanescent waves. Coefficients of transmission and reflection. Brewster and critical angles. Lasers (2 hours): Interaction between light and matter. The Einstein relations. Obtaining and maintaining lasing action. Cavity modes. The properties of laser light. |