The Penguin Dictionary of Physics provides clear and concise definitions for every area of physics - from optics and acoustics to mechanics and electronics, via quantum theory and relativity. The ideal reference guide to this fast-evolving subject, it will prove invaluable to students and teachers, scientists and doctors, and technicians and technologists. The dictionary provides definitions of some 4,600 terms and concepts, with numerous explanatory diagrams and an appendix of scientific tables and symbols.