The Velocity Of Light And Radio Waves

"The man in the mirror is the story of how one of Australian sport's most respected coaches joined the Brisbane Broncos for their inaugural season in 1988 and stayed for 21 seasons."--Blurb.

Electromagnetism began in the nineteenth century when Faraday showed electricity and magnetism were not distinct, separate phenomena, but interacted when there were time-varying electric or magnetic fields. In Electricity and Magnetism I have shown from first principles how Faraday's experiments led finally to Maxwell's four equations, which with the electromagnetic-force law summarise the whole of classical electromagnetism. This book therefore begins with Maxwell's equations and then uses them to study the propagation and generation of electromagnetic waves. Physics is a subject in which the more advanced the treatment of a topic, the deeper the understanding of common occurrences that is revealed. In studying the solutions of Maxwell's equations you will find answers to such questions as: What is an electro magnetic wave? Why does a radio wave travel through space at the speed of light? How is a radio wave generated? Why does light pass through a straight tunnel when a radio wave does not? How does light travel down a curved glass fibre? It is a remarkable fact that the classical laws of electromagnetism are fully consistent with Einstein's special theory of relativity and this is discussed in Chapter 2. The following four chapters provide solutions of Maxwell's equations for the propagation of electro magnetic waves in free space, in dielectrics, across interfaces and in conductors respectively.

A “riveting and thoroughly researched” history of language technology’s effect on society across millennia—from Sumerian syntax to social media hashtags (Phil Lapsley). Writing was born thousands of years ago in Mesopotamia. Spreading to Sumer, and then Egypt, this revolutionary tool allowed rulers to extend their control far and wide, giving rise to the world’s first empires. When Phoenician traders took their alphabet to Greece, literacy’s first boom led to the birth of drama and democracy. In Rome, it helped spell the downfall of the Republic. Later, medieval scriptoria and vernacular bibles gave rise to religious dissent, and with the combination of cheaper paper and Gutenberg’s printing press, the fuse of Reformation was lit. The Industrial Revolution brought the telegraph and the steam driven printing press, allowing information to move faster and wider than ever before through the invention of the newspaper. But along with radio and television, these new technologies were more easily exploited by the powerful, as seen in Germany, the Soviet Union, even Rwanda, where radio incited genocide. With the rise of carbon duplicates (Russian samizdat), photocopying (the Pentagon Papers), the internet, social media, and cell phones (the recent Arab Spring) more people have access to communications, making the world more connected than ever before. This “accessible, quite enjoyable, and highly informative read” will change the way you look at technology, history, and power (Booklist). “[Bernstein] enables us to see what remains the same, even as much has changed.” —Library Journal, “Editors’ Picks” “It brims with interesting ideas and astonishing connections.” —Phil Lapsley, author of Exploding the Phone: The Untold Story of the Teenagers and Outlaws Who Hacked Ma Bell “[Bernstein’s] narrative is succinct and extremely well sourced. . . . [He] reminds us of a number of technologies whose changed roles are less widely chronicled in conventional histories of the media.” —The Irish Times

Wave Propagation and Group Velocity contains papers on group velocity which were published during the First World War and are missing in many libraries. It introduces three different definitions of velocities: the group velocity of Lord Rayleigh, the signal velocity of Sommerfeld, and the velocity of energy transfer, which yields the rate of energy flow through a continuous wave and is strongly related to the characteristic impedance. These three velocities are identical for nonabsorbing media, but they differ considerably in an absorption band. Some examples are discussed in the last chapter dealing with guided waves, and many other cases of application of these definitions are quoted. These problems have come again into the foreground, in connection with the propagation of radio signals and radar. Reflection in the Heaviside layers requires a real knowledge of all these different definitions. Group velocity also plays a very important role in wave mechanics and corresponds to the speed of a particle. The present book should be very useful to physicists and radio engineers and should give them a good basis for new discussions and applications.